Search Results: "bod"

29 September 2025

Russ Allbery: Review: The Incandescent

Review: The Incandescent, by Emily Tesh
Publisher: Tor
Copyright: 2025
ISBN: 1-250-83502-X
Format: Kindle
Pages: 417
The Incandescent is a stand-alone magical boarding school fantasy.
Your students forgot you. It was natural for them to forget you. You were a brief cameo in their lives, a walk-on character from the prologue. For every sentimental my teacher changed my life story you heard, there were dozens of my teacher made me moderately bored a few times a week and then I got through the year and moved on with my life and never thought about them again. They forgot you. But you did not forget them.
Doctor Saffy Walden is Director of Magic at Chetwood, an elite boarding school for prospective British magicians. She has a collection of impressive degrees in academic magic, a specialization in demonic invocation, and a history of vague but lucrative government job offers that go with that specialty. She turned them down to be a teacher, and although she's now in a mostly administrative position, she's a good teacher, with the usual crop of promising, lazy, irritating, and nervous students. As the story opens, Walden's primary problem is Nikki Conway. Or, rather, Walden's primary problem is protecting Nikki Conway from the Marshals, and the infuriating Laura Kenning in particular. When Nikki was seven, she summoned a demon who killed her entire family and left her a ward of the school. To Laura Kenning, that makes her a risk who should ideally be kept far away from invocation. To Walden, that makes Nikki a prodigious natural talent who is developing into a brilliant student and who needs careful, professional training before she's tempted into trying to learn on her own. Most novels with this setup would become Nikki's story. This one does not. The Incandescent is Walden's story. There have been a lot of young-adult magical boarding school novels since Harry Potter became a mass phenomenon, but most of them focus on the students and the inevitable coming-of-age story. This is a story about the teachers: the paperwork, the faculty meetings, the funding challenges, the students who repeat in endless variations, and the frustrations and joys of attempting to grab the interest of a young mind. It's also about the temptation of higher-paying, higher-status, and less ethical work, which however firmly dismissed still nibbles around the edges. Even if you didn't know Emily Tesh is herself a teacher, you would guess that before you get far into this novel. There is a vividness and a depth of characterization that comes from being deeply immersed in the nuance and tedium of the life that your characters are living. Walden's exasperated fondness for her students was the emotional backbone of this book for me. She likes teenagers without idealizing the process of being a teenager, which I think is harder to pull off in a novel than it sounds.
It was hard to quantify the difference between a merely very intelligent student and a brilliant one. It didn't show up in a list of exam results. Sometimes, in fact, brilliance could be a disadvantage when all you needed to do was neatly jump the hoop of an examiner's grading rubric without ever asking why. It was the teachers who knew, the teachers who could feel the difference. A few times in your career, you would have the privilege of teaching someone truly remarkable; someone who was hard work to teach because they made you work harder, who asked you questions that had never occurred to you before, who stretched you to the very edge of your own abilities. If you were lucky as Walden, this time, had been lucky your remarkable student's chief interest was in your discipline: and then you could have the extraordinary, humbling experience of teaching a child whom you knew would one day totally surpass you.
I also loved the world-building, and I say this as someone who is generally not a fan of demons. The demons themselves are a bit of a disappointment and mostly hew to one of the stock demon conventions, but the rest of the magic system is deep enough to have practitioners who approach it from different angles and meaty enough to have some satisfying layered complexity. This is magic, not magical science, so don't expect a fully fleshed-out set of laws, but the magical system felt substantial and satisfying to me. Tesh's first novel, Some Desperate Glory, was by far my favorite science fiction novel of 2023. This is a much different book, which says good things about Tesh's range and the potential of her work yet to come: adult rather than YA, fantasy rather than science fiction, restrained and subtle in places where Some Desperate Glory was forceful and pointed. One thing the books do have in common, though, is some structure, particularly the false climax near the midpoint of the book. I like the feeling of uncertainty and possibility that gives both books, but in the case of The Incandescent, I was not quite in the mood for the second half of the story. My problem with this book is more of a reader preference than an objective critique: I was in the mood for a story about a confident, capable protagonist who was being underestimated, and Tesh was writing a novel with a more complicated and fraught emotional arc. (I'm being intentionally vague to avoid spoilers.) There's nothing wrong with the story that Tesh wanted to tell, and I admire the skill with which she did it, but I got a tight feeling in my stomach when I realized where she was going. There is a satisfying ending, and I'm still very happy I read this book, but be warned that this might not be the novel to read if you're in the mood for a purer competence porn experience. Recommended, and I am once again eagerly awaiting the next thing Emily Tesh writes (and reminding myself to go back and read her novellas). Content warnings: Grievous physical harm, mind control, and some body horror. Rating: 8 out of 10

28 September 2025

Russ Allbery: Review: Echoes of the Imperium

Review: Echoes of the Imperium, by Nicholas & Olivia Atwater
Series: Tales of the Iron Rose #1
Publisher: Starwatch Press
Copyright: 2024
ISBN: 1-998257-04-5
Format: Kindle
Pages: 547
Echoes of the Imperium is a steampunk fantasy adventure novel, the first of a projected series. There is another novella in the series, A Matter of Execution, that takes place chronologically before this novel, but which I am told that you should read afterwards. (I have not yet read it.) If Olivia Atwater's name sounds familiar, it's probably for the romantic fantasy Half a Soul. Nicholas Atwater is her husband. William Blair, a goblin, was a child sailor on the airship HMS Caliban during the final battle that ended the Imperium, and an eyewitness to the destruction of the capital. Like every imperial solider, that loss made him an Oathbreaker; the fae Oath that he swore to defend the Imperium did not care that nothing a twelve-year-old boy could have done would have changed the result of the battle. He failed to kill himself with most of the rest of the crew, and thus was taken captive by the Coalition. Twenty years later, William Blair is the goblin captain of the airship Iron Rose. It's an independent transport ship that takes various somewhat-dodgy contracts and has to avoid or fight through pirates. The crew comes from both sides of the war and has built their own working truce. Blair himself is a somewhat manic but earnest captain who doesn't entirely believe he deserves that role, one who tends more towards wildly risky plans and improvisation than considered and sober decisions. The rest of the crew are the sort of wild mix of larger-than-life personality quirks that populate swashbuckling adventure books but leave me dubious that stuffing that many high-maintenance people into one ship would go as well as it does. I did appreciate the gunnery knitting circle, though. Echoes of the Imperium is told in the first person from Blair's perspective in two timelines. One follows Blair in the immediate aftermath of the war, tracing his path to becoming an airship captain and meeting some of the people who will later be part of his crew. The other is the current timeline, in which Blair gets deeper and deeper into danger by accepting a risky contract with unexpected complications. Neither of these timelines are in any great hurry to arrive at some destination, and that's the largest problem with this book. Echoes of the Imperium is long, sprawling, and unwilling to get anywhere near any sort of a point until the reader is deeply familiar with the horrific aftermath of the war, the mountains guilt and trauma many of the characters carry around, and Blair's impostor syndrome and feelings of inadequacy. For the first half of this book, I was so bored. I almost bailed out; only a few flashes of interesting character interactions and hints of world-building helped me drag myself through all of the tedious setup. What saves this book is that the world-building is a delight. Once the characters finally started engaging with it in earnest, I could not put it down. Present-time Blair is no longer an Oathbreaker because he was forgiven by a fairy; this will become important later. The sites of great battles are haunted by ghostly echoes of the last moments of the lives of those who died (hence the title); this will become very important later. Blair has a policy of asking no questions about people's pasts if they're willing to commit to working with the rest of the crew; this, also, will become important later. All of these tidbits the authors drop into the story and then ignore for hundreds of pages do have a payoff if you're willing to wait for it. As the reader (too) slowly discovers, the Atwaters' world is set in a war of containment by light fae against dark fae. Instead of being inscrutable and separate, the fae use humans and human empires as tools in that war. The fallen Imperium was a bastion of fae defense, and the war that led to the fall of that Imperium was triggered by the price its citizens paid for that defense, one that the fae could not possibly care less about. The creatures may be out of epic fantasy and the technology from the imagined future of Victorian steampunk, but the politics are that of the Cold War and containment strategies. This book has a lot to say about colonialism and empire, but it says those things subtly and from a fantasy slant, in a world with magical Oaths and direct contact with powers that are both far beyond the capabilities of the main characters and woefully deficient in in humanity and empathy. It has a bit of the feel of Greek mythology if the gods believed in an icy realpolitik rather than embodying the excesses of human emotion. The second half of this book was fantastic. The found-family vibe among a crew of high-maintenance misfits that completely failed to cohere for me in the first half of the book, while Blair was wallowing in his feelings and none of the events seemed to matter, came together brilliantly as soon as the crew had a real problem and some meaty world-building and plot to sink their teeth into. There is a delightfully competent teenager, some satisfying competence porn that Blair finally stops undermining, and a sharp political conflict that felt emotionally satisfying, if perhaps not that intellectually profound. In short, it turns into the fun, adventurous romp of larger-than-life characters that the setting promises. Even the somewhat predictable mid-book reveal worked for me, in part because the emotions of the characters around that reveal sold its impact. If you're going to write a book with a bad half and a good half, it's always better to put the good half second. I came away with very positive feelings about Echoes of the Imperium and a tentative willingness to watch for the sequel. (It reaches a fairly satisfying conclusion, but there are a lot of unresolved plot hooks.) I'm a bit hesitant to recommend it, though, because the first half was not very fun. I want to say that about 75% of the first half of the book could have been cut and the book would have been stronger for it. I'm not completely sure I'm right, since the Atwaters were laying the groundwork for a lot of payoff, but I wish that groundwork hadn't been as much of a slog. Tentatively recommended, particularly if you're in the mood for steampunk fae mythology, but know that this book requires some investment. Technically, A Matter of Execution comes first, but I plan to read it as a sequel. Rating: 8 out of 10

23 September 2025

Ravi Dwivedi: Singapore Trip

In December 2024, I went on a trip through four countries - Singapore, Malaysia, Brunei, and Vietnam - with my friend Badri. This post covers our experiences in Singapore. I took an IndiGo flight from Delhi to Singapore, with a layover in Chennai. At the Chennai airport, I was joined by Badri. We had an early morning flight from Chennai that would land in Singapore in the afternoon. Within 48 hours of our scheduled arrival in Singapore, we submitted an arrival card online. At immigration, we simply needed to scan our passports at the gates, which opened automatically to let us through, and then give our address to an official nearby. The process was quick and smooth, but it unfortunately meant that we didn t get our passports stamped by Singapore. Before I left the airport, I wanted to visit the nature-themed park with a fountain I saw in pictures online. It is called Jewel Changi, and it took quite some walking to get there. After reaching the park, we saw a fountain that could be seen from all the levels. We roamed around for a couple of hours, then proceeded to the airport metro station to get to our hotel.
Jewel Changi A shot of Jewel Changi. Photo by Ravi Dwivedi. Released under the CC-BY-SA 4.0.
There were four ATMs on the way to the metro station, but none of them provided us with any cash. This was the first country (outside India, of course!) where my card didn t work at ATMs. To use the metro, one can tap the EZ-Link card or bank cards at the AFC gates to get in. You cannot buy tickets using cash. Before boarding the metro, I used my credit card to get Badri an EZ-Link card from a vending machine. It was 10 Singapore dollars ( 630) - 5 for the card, and 5 for the balance. I had planned to use my Visa credit card to pay for my own fare. I was relieved to see that my card worked, and I passed through the AFC gates. We had booked our stay at a hostel named Campbell s Inn, which was the cheapest we could find in Singapore. It was 1500 per night for dorm beds. The hostel was located in Little India. While Little India has an eponymous metro station, the one closest to our hostel was Rochor. On the way to the hostel, we found out that our booking had been canceled. We had booked from the Hostelworld website, opting to pay the deposit in advance and to pay the balance amount in person upon reaching. However, Hostelworld still tried to charge Badri s card again before our arrival. When the unauthorized charge failed, they sent an automatic message saying we tried to charge and to contact them soon to avoid cancellation, which we couldn t do as we were in the plane. Despite this, we went to the hostel to check the status of our booking. The trip from the airport to Rochor required a couple of transfers. It was 2 Singapore dollars (approx. 130) and took approximately an hour. Upon reaching the hostel, we were informed that our booking had indeed been canceled, and were not given any reason for the cancelation. Furthermore, no beds were available at the hostel for us to book on the spot. We decided to roam around and look for accommodation at other hostels in the area. Soon, we found a hostel by the name of Snooze Inn, which had two beds available. It was 36 Singapore dollars per person (around 2300) for a dormitory bed. Snooze Inn advertised supporting RuPay cards and UPI. Some other places in that area did the same. We paid using my card. We checked in and slept for a couple of hours after taking a shower. By the time we woke up, it was dark. We met Praveen s friend Sabeel to get my FLX1 phone. We also went to Mustafa Center nearby to exchange Indian rupees for Singapore dollars. Mustafa Center also had a shopping center with shops selling electronic items and souvenirs, among other things. When we were dropping off Sabeel at a bus stop, we discovered that the bus stops in Singapore had a digital board mentioning the bus routes for the stop and the number of minutes each bus was going to take. In addition to an organized bus system, Singapore had good pedestrian infrastructure. There were traffic lights and zebra crossings for pedestrians to cross the roads. Unlike in Indian cities, rules were being followed. Cars would stop for pedestrians at unmanaged zebra crossings; pedestrians would in turn wait for their crossing signal to turn green before attempting to walk across. Therefore, walking in Singapore was easy. Traffic rules were taken so seriously in Singapore I (as a pedestrian) was afraid of unintentionally breaking them, which could get me in trouble, as breaking rules is dealt with heavy fines in the country. For example, crossing roads without using a marked crossing (while being within 50 meters of it) - also known as jaywalking - is an offence in Singapore. Moreover, the streets were litter-free, and cleanliness seemed like an obsession. After exploring Mustafa Center, we went to a nearby 7-Eleven to top up Badri s EZ-Link card. He gave 20 Singapore dollars for the recharge, which credited the card by 19.40 Singapore dollars (0.6 dollars being the recharge fee). When I was planning this trip, I discovered that the World Chess Championship match was being held in Singapore. I seized the opportunity and bought a ticket in advance. The next day - the 5th of December - I went to watch the 9th game between Gukesh Dommaraju of India and Ding Liren of China. The venue was a hotel on Sentosa Island, and the ticket was 70 Singapore dollars, which was around 4000 at the time. We checked out from our hostel in the morning, as we were planning to stay with Badri s aunt that night. We had breakfast at a place in Little India. Then we took a couple of buses, followed by a walk to Sentosa Island. Paying the fare for the buses was similar to the metro - I tapped my credit card in the bus, while Badri tapped his EZ-Link card. We also had to tap it while getting off. If you are tapping your credit card to use public transport in Singapore, keep in mind that the total amount of all the trips taken on a day is deducted at the end. This makes it hard to determine the cost of individual trips. For example, I could take a bus and get off after tapping my card, but I would have no way to determine how much this journey cost. When you tap in, the maximum fare amount gets deducted. When you tap out, the balance amount gets refunded (if it s a shorter journey than the maximum fare one). So, there is incentive for passengers not to get off without tapping out. Going by your card statement, it looks like all that happens virtually, and only one statement comes in at the end. Maybe this combining only happens for international cards. We got off the bus a kilometer away from Sentosa Island and walked the rest of the way. We went on the Sentosa Boardwalk, which is itself a tourist attraction. I was using Organic Maps to navigate to the hotel Resorts World Sentosa, but Organic Maps route led us through an amusement park. I tried asking the locals (people working in shops) for directions, but it was a Chinese-speaking region, and they didn t understand English. Fortunately, we managed to find a local who helped us with the directions.
Sentosa Boardwalk A shot of Sentosa Boardwalk. Photo by Ravi Dwivedi. Released under the CC-BY-SA 4.0.
Following the directions, we somehow ended up having to walk on a road which did not have pedestrian paths. Singapore is a country with strict laws, so we did not want to walk on that road. Avoiding that road led us to the Michael Hotel. There was a person standing at the entrance, and I asked him for directions to Resorts World Sentosa. The person told me that the bus (which was standing at the entrance) would drop me there! The bus was a free service for getting to Resorts World Sentosa. Here I parted ways with Badri, who went to his aunt s place. I got to the Resorts Sentosa and showed my ticket to get in. There were two zones inside - the first was a room with a glass wall separating the audience and the players. This was the room to watch the game physically, and resembled a zoo or an aquarium. :) The room was also a silent room, which means talking or making noise was prohibited. Audiences were only allowed to have mobile phones for the first 30 minutes of the game - since I arrived late, I could not bring my phone inside that room. The other zone was outside this room. It had a big TV on which the game was being broadcast along with commentary by David Howell and Jovanka Houska - the official FIDE commentators for the event. If you don t already know, FIDE is the authoritative international chess body. I spent most of the time outside that silent room, giving me an opportunity to socialize. A lot of people were from Singapore. I saw there were many Indians there as well. Moreover, I had a good time with Vasudevan, a journalist from Tamil Nadu who was covering the match. He also asked questions to Gukesh during the post-match conference. His questions were in Tamil to lift Gukesh s spirits, as Gukesh is a Tamil speaker. Tea and coffee were free for the audience. I also bought a T-shirt from their stall as a souvenir. After the game, I took a shuttle bus from Resorts World Sentosa to a metro station, then travelled to Pasir Ris by metro, where Badri was staying with his aunt. I thought of getting something to eat, but could not find any caf s or restaurants while I was walking from the Pasir Ris metro station to my destination, and was positively starving when I got there. Badri s aunt s place was an apartment in a gated community. On the gate was a security guard who asked me the address of the apartment. Upon entering, there were many buildings. To enter the building, you need to dial the number of the apartment you want to go to and speak to them. I had seen that in the TV show Seinfeld, where Jerry s friends used to dial Jerry to get into his building. I was afraid they might not have anything to eat because I told them I was planning to get something on the way. This was fortunately not the case, and I was relieved to not have to sleep with an empty stomach. Badri s uncle gave us an idea of how safe Singapore is. He said that even if you forget your laptop in a public space, you can go back the next day to find it right there in the same spot. I also learned that owning cars was discouraged in Singapore - the government imposes a high registration fee on them, while also making public transport easy to use and affordable. I also found out that 7-Eleven was not that popular among residents in Singapore, unlike in Malaysia or Thailand. The next day was our third and final day in Singapore. We had a bus in the evening to Johor Bahru in Malaysia. We got up early, had breakfast, and checked out from Badri s aunt s home. A store by the name of Cat Socrates was our first stop for the day, as Badri wanted to buy some stationery. The plan was to take the metro, followed by the bus. So we got to Pasir Ris metro station. Next to the metro station was a mall. In the mall, Badri found an ATM where our cards worked, and we got some Singapore dollars. It was noon when we reached the stationery shop mentioned above. We had to walk a kilometer from the place where the bus dropped us. It was a hot, sunny day in Singapore, so walking was not comfortable. We had to go through residential areas in Singapore. We saw some non-touristy parts of Singapore. After we were done with the stationery shop, we went to a hawker center to get lunch. Hawker centers are unique to Singapore. They have a lot of shops that sell local food at cheap prices. It is similar to a food court. However, unlike the food courts in malls, hawker centers are open-air and can get quite hot.
Jewel Changi This is the hawker center we went to. Photo by Ravi Dwivedi. Released under the CC-BY-SA 4.0.
To have something, you just need to buy it from one of the shops and find a table. After you are done, you need to put your tray in the tray-collecting spots. I had a kaya toast with chai, since there weren t many vegetarian options. I also bought a persimmon from a nearby fruit vendor. On the other hand, Badri sampled some local non-vegetarian dishes.
A sign saying, 'No table littering, by law.' Table littering at the hawker center was prohibited by law. Photo by Ravi Dwivedi. Released under the CC-BY-SA 4.0.
Next, we took a metro to Raffles Place, as we wanted to visit Merlion, the icon of Singapore. It is a statue having the head of a lion and the body of a fish. While getting through the AFC gates, my card was declined. Therefore, I had to buy an EZ-Link card, which I had been avoiding because the card itself costs 5 Singapore dollars. From the Raffles Place metro station, we walked to Merlion. The place also gave a nice view of Marina Bay Sands. It was filled with tourists clicking pictures, and we also did the same.
Merlion from behind Merlion from behind, giving a good view of Marina Bay Sands. Photo by Ravi Dwivedi. Released under the CC-BY-SA 4.0.
After this, we went to the bus stop to catch our bus to the border city of Johor Bahru, Malaysia. The bus was more than an hour late, and we worried that we had missed the bus. I asked an Indian woman at the stop who also planned to take the same bus, and she told us that the bus was late. Finally, our bus arrived, and we set off for Johor Bahru. Before I finish, let me give you an idea of my expenditure. Singapore is an expensive country, and I realized that expenses could go up pretty quickly. Overall, my stay in Singapore for 3 days and 2 nights was approx. 5500 rupees. That too, when we stayed one night at Badri s aunt s place (so we didn t have to pay for accomodation for one of the nights) and didn t have to pay for a couple of meals. This amount doesn t include the ticket for the chess game, but includes the costs of getting there. If you are in Singapore, it is likely you will pay a visit to Sentosa Island anyway. Stay tuned for our experiences in Malaysia! Credits: Thanks to Dione, Sahil, Badri and Contrapunctus for reviewing the draft. Thanks to Bhe for spotting a duplicate sentence.

22 September 2025

Vincent Bernat: Akvorado release 2.0

Akvorado 2.0 was released today! Akvorado collects network flows with IPFIX and sFlow. It enriches flows and stores them in a ClickHouse database. Users can browse the data through a web console. This release introduces an important architectural change and other smaller improvements. Let s dive in!
$ git diff --shortstat v1.11.5
 493 files changed, 25015 insertions(+), 21135 deletions(-)

New outlet service The major change in Akvorado 2.0 is splitting the inlet service into two parts: the inlet and the outlet. Previously, the inlet handled all flow processing: receiving, decoding, and enrichment. Flows were then sent to Kafka for storage in ClickHouse:
Akvorado flow processing before the change: flows are received and processed by the inlet, sent to Kafka and stored in ClickHouse
Akvorado flow processing before the introduction of the outlet service
Network flows reach the inlet service using UDP, an unreliable protocol. The inlet must process them fast enough to avoid losing packets. To handle a high number of flows, the inlet spawns several sets of workers to receive flows, fetch metadata, and assemble enriched flows for Kafka. Many configuration options existed for scaling, which increased complexity for users. The code needed to avoid blocking at any cost, making the processing pipeline complex and sometimes unreliable, particularly the BMP receiver.1 Adding new features became difficult without making the problem worse.2 In Akvorado 2.0, the inlet receives flows and pushes them to Kafka without decoding them. The new outlet service handles the remaining tasks:
Akvorado flow processing after the change: flows are received by the inlet, sent to Kafka, processed by the outlet and inserted in ClickHouse
Akvorado flow processing after the introduction of the outlet service
This change goes beyond a simple split:3 the outlet now reads flows from Kafka and pushes them to ClickHouse, two tasks that Akvorado did not handle before. Flows are heavily batched to increase efficiency and reduce the load on ClickHouse using ch-go, a low-level Go client for ClickHouse. When batches are too small, asynchronous inserts are used (e20645). The number of outlet workers scales dynamically (e5a625) based on the target batch size and latency (50,000 flows and 5 seconds by default). This new architecture also allows us to simplify and optimize the code. The outlet fetches metadata synchronously (e20645). The BMP component becomes simpler by removing cooperative multitasking (3b9486). Reusing the same RawFlow object to decode protobuf-encoded flows from Kafka reduces pressure on the garbage collector (8b580f). The effect on Akvorado s overall performance was somewhat uncertain, but a user reported 35% lower CPU usage after migrating from the previous version, plus resolution of the long-standing BMP component issue.

Other changes This new version includes many miscellaneous changes, such as completion for source and destination ports (f92d2e), and automatic restart of the orchestrator service (0f72ff) when configuration changes to avoid a common pitfall for newcomers. Let s focus on some key areas for this release: observability, documentation, CI, Docker, Go, and JavaScript.

Observability Akvorado exposes metrics to provide visibility into the processing pipeline and help troubleshoot issues. These are available through Prometheus HTTP metrics endpoints, such as /api/v0/inlet/metrics. With the introduction of the outlet, many metrics moved. Some were also renamed (4c0b15) to match Prometheus best practices. Kafka consumer lag was added as a new metric (e3a778). If you do not have your own observability stack, the Docker Compose setup shipped with Akvorado provides one. You can enable it by activating the profiles introduced for this purpose (529a8f). The prometheus profile ships Prometheus to store metrics and Alloy to collect them (2b3c46, f81299, and 8eb7cd). Redis and Kafka metrics are collected through the exporter bundled with Alloy (560113). Other metrics are exposed using Prometheus metrics endpoints and are automatically fetched by Alloy with the help of some Docker labels, similar to what is done to configure Traefik. cAdvisor was also added (83d855) to provide some container-related metrics. The loki profile ships Loki to store logs (45c684). While Alloy can collect and ship logs to Loki, its parsing abilities are limited: I could not find a way to preserve all metadata associated with structured logs produced by many applications, including Akvorado. Vector replaces Alloy (95e201) and features a domain-specific language, VRL, to transform logs. Annoyingly, Vector currently cannot retrieve Docker logs from before it was started. Finally, the grafana profile ships Grafana, but the shipped dashboards are broken. This is planned for a future version.

Documentation The Docker Compose setup provided by Akvorado makes it easy to get the web interface up and running quickly. However, Akvorado requires a few mandatory steps to be functional. It ships with comprehensive documentation, including a chapter about troubleshooting problems. I hoped this documentation would reduce the support burden. It is difficult to know if it works. Happy users rarely report their success, while some users open discussions asking for help without reading much of the documentation. In this release, the documentation was significantly improved.
$ git diff --shortstat v1.11.5 -- console/data/docs
 10 files changed, 1873 insertions(+), 1203 deletions(-)
The documentation was updated (fc1028) to match Akvorado s new architecture. The troubleshooting section was rewritten (17a272). Instructions on how to improve ClickHouse performance when upgrading from versions earlier than 1.10.0 was added (5f1e9a). An LLM proofread the entire content (06e3f3). Developer-focused documentation was also improved (548bbb, e41bae, and 871fc5). From a usability perspective, table of content sections are now collapsable (c142e5). Admonitions help draw user attention to important points (8ac894).
Admonition in Akvorado documentation to ask a user not to open an issue or start a discussion before reading the documentation
Example of use of admonitions in Akvorado's documentation

Continuous integration This release includes efforts to speed up continuous integration on GitHub. Coverage and race tests run in parallel (6af216 and fa9e48). The Docker image builds during the tests but gets tagged only after they succeed (8b0dce).
GitHub workflow for CI with many jobs, some of them running in parallel, some not
GitHub workflow to test and build Akvorado
End-to-end tests (883e19) ensure the shipped Docker Compose setup works as expected. Hurl runs tests on various HTTP endpoints, particularly to verify metrics (42679b and 169fa9). For example:
## Test inlet has received NetFlow flows
GET http://127.0.0.1:8080/prometheus/api/v1/query
[Query]
query: sum(akvorado_inlet_flow_input_udp_packets_total job="akvorado-inlet",listener=":2055" )
HTTP 200
[Captures]
inlet_receivedflows: jsonpath "$.data.result[0].value[1]" toInt
[Asserts]
variable "inlet_receivedflows" > 10
## Test inlet has sent them to Kafka
GET http://127.0.0.1:8080/prometheus/api/v1/query
[Query]
query: sum(akvorado_inlet_kafka_sent_messages_total job="akvorado-inlet" )
HTTP 200
[Captures]
inlet_sentflows: jsonpath "$.data.result[0].value[1]" toInt
[Asserts]
variable "inlet_sentflows" >=   inlet_receivedflows  

Docker Akvorado ships with a comprehensive Docker Compose setup to help users get started quickly. It ensures a consistent deployment, eliminating many configuration-related issues. It also serves as a living documentation of the complete architecture. This release brings some small enhancements around Docker: Previously, many Docker images were pulled from the Bitnami Containers library. However, VMWare acquired Bitnami in 2019 and Broadcom acquired VMWare in 2023. As a result, Bitnami images were deprecated in less than a month. This was not really a surprise4. Previous versions of Akvorado had already started moving away from them. In this release, the Apache project s Kafka image replaces the Bitnami one (1eb382). Thanks to the switch to KRaft mode, Zookeeper is no longer needed (0a2ea1, 8a49ca, and f65d20). Akvorado s Docker images were previously compiled with Nix. However, building AArch64 images on x86-64 is slow because it relies on QEMU userland emulation. The updated Dockerfile uses multi-stage and multi-platform builds: one stage builds the JavaScript part on the host platform, one stage builds the Go part cross-compiled on the host platform, and the final stage assembles the image on top of a slim distroless image (268e95 and d526ca).
# This is a simplified version
FROM --platform=$BUILDPLATFORM node:20-alpine AS build-js
RUN apk add --no-cache make
WORKDIR /build
COPY console/frontend console/frontend
COPY Makefile .
RUN make console/data/frontend
FROM --platform=$BUILDPLATFORM golang:alpine AS build-go
RUN apk add --no-cache make curl zip
WORKDIR /build
COPY . .
COPY --from=build-js /build/console/data/frontend console/data/frontend
RUN go mod download
RUN make all-indep
ARG TARGETOS TARGETARCH TARGETVARIANT VERSION
RUN make
FROM gcr.io/distroless/static:latest
COPY --from=build-go /build/bin/akvorado /usr/local/bin/akvorado
ENTRYPOINT [ "/usr/local/bin/akvorado" ]
When building for multiple platforms with --platform linux/amd64,linux/arm64,linux/arm/v7, the build steps until the highlighted line execute only once for all platforms. This significantly speeds up the build. Akvorado now ships Docker images for these platforms: linux/amd64, linux/amd64/v3, linux/arm64, and linux/arm/v7. When requesting ghcr.io/akvorado/akvorado, Docker selects the best image for the current CPU. On x86-64, there are two choices. If your CPU is recent enough, Docker downloads linux/amd64/v3. This version contains additional optimizations and should run faster than the linux/amd64 version. It would be interesting to ship an image for linux/arm64/v8.2, but Docker does not support the same mechanism for AArch64 yet (792808).

Go This release includes many changes related to Go but not visible to the users.

Toolchain In the past, Akvorado supported the two latest Go versions, preventing immediate use of the latest enhancements. The goal was to allow users of stable distributions to use Go versions shipped with their distribution to compile Akvorado. However, this became frustrating when interesting features, like go tool, were released. Akvorado 2.0 requires Go 1.25 (77306d) but can be compiled with older toolchains by automatically downloading a newer one (94fb1c).5 Users can still override GOTOOLCHAIN to revert this decision. The recommended toolchain updates weekly through CI to ensure we get the latest minor release (5b11ec). This change also simplifies updates to newer versions: only go.mod needs updating. Thanks to this change, Akvorado now uses wg.Go() (77306d) and I have started converting some unit tests to the new test/synctest package (bd787e, 7016d8, and 159085).

Testing When testing equality, I use a helper function Diff() to display the differences when it fails:
got := input.Keys()
expected := []int 1, 2, 3 
if diff := helpers.Diff(got, expected); diff != ""  
    t.Fatalf("Keys() (-got, +want):\n%s", diff)
 
This function uses kylelemons/godebug. This package is no longer maintained and has some shortcomings: for example, by default, it does not compare struct private fields, which may cause unexpectedly successful tests. I replaced it with google/go-cmp, which is stricter and has better output (e2f1df).

Another package for Kafka Another change is the switch from Sarama to franz-go to interact with Kafka (756e4a and 2d26c5). The main motivation for this change is to get a better concurrency model. Sarama heavily relies on channels and it is difficult to understand the lifecycle of an object handed to this package. franz-go uses a more modern approach with callbacks6 that is both more performant and easier to understand. It also ships with a package to spawn fake Kafka broker clusters, which is more convenient than the mocking functions provided by Sarama.

Improved routing table for BMP To store its routing table, the BMP component used kentik/patricia, an implementation of a patricia tree focused on reducing garbage collection pressure. gaissmai/bart is a more recent alternative using an adaptation of [Donald Knuth s ART algorithm][] that promises better performance and delivers it: 90% faster lookups and 27% faster insertions (92ee2e and fdb65c). Unlike kentik/patricia, gaissmai/bart does not help efficiently store values attached to each prefix. I adapted the same approach as kentik/patricia to store route lists for each prefix: store a 32-bit index for each prefix, and use it to build a 64-bit index for looking up routes in a map. This leverages Go s efficient map structure. gaissmai/bart also supports a lockless routing table version, but this is not simple because we would need to extend this to the map storing the routes and to the interning mechanism. I also attempted to use Go s new unique package to replace the intern package included in Akvorado, but performance was worse.7

Miscellaneous Previous versions of Akvorado were using a custom Protobuf encoder for performance and flexibility. With the introduction of the outlet service, Akvorado only needs a simple static schema, so this code was removed. However, it is possible to enhance performance with planetscale/vtprotobuf (e49a74, and 8b580f). Moreover, the dependency on protoc, a C++ program, was somewhat annoying. Therefore, Akvorado now uses buf, written in Go, to convert a Protobuf schema into Go code (f4c879). Another small optimization to reduce the size of the Akvorado binary by 10 MB was to compress the static assets embedded in Akvorado in a ZIP file. It includes the ASN database, as well as the SVG images for the documentation. A small layer of code makes this change transparent (b1d638 and e69b91).

JavaScript Recently, two large supply-chain attacks hit the JavaScript ecosystem: one affecting the popular packages chalk and debug and another impacting the popular package @ctrl/tinycolor. These attacks also exist in other ecosystems, but JavaScript is a prime target due to heavy use of small third-party dependencies. The previous version of Akvorado relied on 653 dependencies. npm-run-all was removed (3424e8, 132 dependencies). patch-package was removed (625805 and e85ff0, 69 dependencies) by moving missing TypeScript definitions to env.d.ts. eslint was replaced with oxlint, a linter written in Rust (97fd8c, 125 dependencies, including the plugins). I switched from npm to Pnpm, an alternative package manager (fce383). Pnpm does not run install scripts by default8 and prevents installing packages that are too recent. It is also significantly faster.9 Node.js does not ship Pnpm but it ships Corepack, which allows us to use Pnpm without installing it. Pnpm can also list licenses used by each dependency, removing the need for license-compliance (a35ca8, 42 dependencies). For additional speed improvements, beyond switching to Pnpm and Oxlint, Vite was replaced with its faster Rolldown version (463827). After these changes, Akvorado only pulls 225 dependencies.

Next steps I would like to land three features in the next version of Akvorado:
  • Add Grafana dashboards to complete the observability stack. See issue #1906 for details.
  • Integrate OVH s Grafana plugin by providing a stable API for such integrations. Akvorado s web console would still be useful for browsing results, but if you want to build and share dashboards, you should switch to Grafana. See issue #1895.
  • Move some work currently done in ClickHouse (custom dictionaries, GeoIP and IP enrichment) back into the outlet service. This should give more flexibility for adding features like the one requested in issue #1030. See issue #2006.

I started working on splitting the inlet into two parts more than one year ago. I found more motivation in recent months, partly thanks to Claude Code, which I used as a rubber duck. Almost none of the produced code was kept:10 it is like an intern who does not learn.

  1. Many attempts were made to make the BMP component both performant and not blocking. See for example PR #254, PR #255, and PR #278. Despite these efforts, this component remained problematic for most users. See issue #1461 as an example.
  2. Some features have been pushed to ClickHouse to avoid the processing cost in the inlet. See for example PR #1059.
  3. This is the biggest commit:
    $ git show --shortstat ac68c5970e2c   tail -1
    231 files changed, 6474 insertions(+), 3877 deletions(-)
    
  4. Broadcom is known for its user-hostile moves. Look at what happened with VMWare.
  5. As a Debian developer, I dislike these mechanisms that circumvent the distribution package manager. The final straw came when Go 1.25 spent one month in the Debian NEW queue, an arbitrary mechanism I don t like at all.
  6. In the early years of Go, channels were heavily promoted. Sarama was designed during this period. A few years later, a more nuanced approach emerged. See notably Go channels are bad and you should feel bad.
  7. This should be investigated further, but my theory is that the intern package uses 32-bit integers, while unique uses 64-bit pointers. See commit 74e5ac.
  8. This is also possible with npm. See commit dab2f7.
  9. An even faster alternative is Bun, but it is less available.
  10. The exceptions are part of the code for the admonition blocks, the code for collapsing the table of content, and part of the documentation.

21 September 2025

Joey Hess: cheap DIY solar fence design

A year ago I installed a 4 kilowatt solar fence. I'm revisiting it this Sun Day, to share the design, now that I have prooved it out.
The solar fence and some other ground and pole mount solar panels, seen through leaves.
Solar fencing manufacturers have some good simple designs, but it's hard to buy for a small installation. They are selling to utility scale solar mostly. And those are installed by driving metal beams into the ground, which requires heavy machinery. Since I have experience with Ironridge rails for roof mount solar, I decided to adapt that system for a vertical mount. Which is something it was not designed for. I combined the Ironridge hardware with regular parts from the hardware store. The cost of mounting solar panels nowadays is often higher than the cost of the panels. I hoped to match the cost, and I nearly did. The solar panels cost $100 each, and the fence cost $110 per solar panel. This fence was significantly cheaper than conventional ground mount arrays that I considered as alternatives, and made a better use of a difficult hillside location. I used 7 foot long Ironridge XR-10 rails, which fit 2 solar panels per rail. (Longer rails would need a center post anyway, and the 7 foot long rails have cheaper shipping, since they do not need to be shipped freight.) For the fence posts, I used regular 4x4" treated posts. 12 foot long, set in 3 foot deep post holes, with 3x 50 lb bags of concrete per hole and 6 inches of gravel on the bottom.
detail of how the rails are mounted to the posts, and the panels to the rails
To connect the Ironridge rails to the fence posts, I used the Ironridge LFT-03-M1 slotted L-foot bracket. Screwed into the post with a 5/8 x 3 inch hot-dipped galvanized lag screw. Since a treated post can react badly with an aluminum bracket, there needs to be some flashing between the post and bracket. I used Shurtape PW-100 tape for that. I see no sign of corrosion after 1 year. The rest of the Ironridge system is a T-bolt that connects the rail to the L-foot (part BHW-SQ-02-A1), and Ironridge solar panel fasteners (UFO-CL-01-A1 and UFO-STP-40MM-M1). Also XR-10 end caps and wire clips. Since the Ironridge hardware is not designed to hold a solar panel at a 90 degree angle, I was concerned that the panels might slide downward over time. To help prevent that, I added some additional support brackets under the bottom of the panels. So far, that does not seem to have been a problem though. I installed Aptos 370 watt solar panels on the fence. They are bifacial, and while the posts block the back partially, there is still bifacial gain on cloudy days. I left enough space under the solar panels to be able to run a push mower under them.
Me standing in front of the solar fence at end of construction
I put pairs of posts next to one-another, so each 7 foot segment of fence had its own 2 posts. This is the least elegant part of this design, but fitting 2 brackets next to one-another on a single post isn't feasible. I bolted the pairs of posts together with some spacers. A side benefit of doing it this way is that treated lumber can warp as it dries, and this prevented much twisting of the posts. Using separate posts for each segment also means that the fence can traverse a hill easily. And it does not need to be perfectly straight. In fact, my fence has a 30 degree bend in the middle. This means it has both south facing and south-west facing panels, so can catch the light for longer during the day. After building the fence, I noticed there was a slight bit of sway at the top, since 9 feet of wooden post is not entirely rigid. My worry was that a gusty wind could rattle the solar panels. While I did not actually observe that happening, I added some diagonal back bracing for peace of mind.
view of rear upper corner of solar fence, showing back bracing connection
Inspecting the fence today, I find no problems after the first year. I hope it will last 30 years, with the lifespan of the treated lumber being the likely determining factor. As part of my larger (and still ongoing) ground mount solar install, the solar fence has consistently provided great power. The vertical orientation works well at latitude 36. It also turned out that the back of the fence was useful to hang conduit and wiring and solar equipment, and so it turned into the electrical backbone of my whole solar field. But that's another story.. solar fence parts list
quantity cost per unit description
10 $27.89 7 foot Ironridge XR-10 rail
12 $20.18 12 foot treated 4x4
30 $4.86 Ironridge UFO-CL-01-A1
20 $0.87 Ironridge UFO-STP-40MM-M1
1 $12.62 Ironridge XR-10 end caps (20 pack)
20 $2.63 Ironridge LFT-03-M1
20 $1.69 Ironridge BHW-SQ-02-A1
22 $2.65 5/8 x 3 inch hot-dipped galvanized lag screw
10 $0.50 6 gravel per post
30 $6.91 50 lb bags of quickcrete
1 $15.00 Shurtape PW-100 Corrosion Protection Pipe Wrap Tape
N/A $30 other bolts and hardware (approximate)
$1100 total (Does not include cost of panels, wiring, or electrical hardware.)

12 September 2025

Christoph Berg: The Cost of TDE and Checksums in PGEE

It's been a while since the last performance check of Transparent Data Encryption (TDE) in Cybertec's PGEE distribution - that was in 2016. Of course, the question is still interesting, so I did some benchmarks. Since the difference is really small between running without any extras, with data checksums turned on, and with both encryption and checksums turned on, we need to pick a configuration that will stress-test these features the most. So in the spirit of making PostgreSQL deliberately run slow, I went with only 1MB of shared_buffers with a pgbench workload of scale factor 50. The 770MB of database size will easily fit into RAM. However, having such a small buffer cache setting will cause a lot of cache misses with pages re-read from the OS disk cache, checksums checked, and the page decrypted again. To further increase the effect, I ran pgbench --skip-some-updates so the smaller, in-cache-anyway pgbench tables are not touched. Overall, this yields a pretty consistent buffer cache hit rate of only 82.8%. Here are the PGEE 17.6 tps (transactions per second) numbers averaged over a few 1-minute 3-client pgbench runs for different combinations of data checksums on/off, TDE off, and the various supported key bit lengths:
no checksums data checksums
no TDE 2455,6 100,00 % 2449,7 99,76 %
128 bits 2440,9 99,40 % 2443,3 99,50 %
192 bits 2439,6 99,35 % 2446,1 99,61 %
256 bits 2450,3 99,78 % 2443,1 99,49 %
There is a lot of noise in the individual runtimes before averaging, so the numbers must be viewed with some care (192-bit TDE is certainly not faster with checksums than without), but if we dare to interpret these tiny differences, we can conclude the following: Any workload with a better shared_buffers cache hit rate would see a lower penalty of enabling checksums and TDE than that. The post The Cost of TDE and Checksums in PGEE appeared first on CYBERTEC PostgreSQL Services & Support.

Freexian Collaborators: Using JavaScript in Debusine without depending on JavaScript (by Enrico Zini)

Debusine is a tool designed for Debian developers and Operating System developers in general. This posts describes our approach to the use of JavaScript, and some practical designs we came up with to integrate it with Django with minimal effort.

Debusine web UI and JavaScript Debusine currently has 3 user interfaces: a client on the command line, a RESTful API, and a Django-based Web UI. Debusine s web UI is a tool to interact with the system, and we want to spend most of our efforts in creating a system that works and works well, rather than chasing the latest and hippest of the frontend frameworks for the web. Also, Debian as a community has an aversion to having parts of the JavaScript ecosystem in the critical path of its core infrastructure, and in our professional experience this aversion is not at all unreasonable. This leads to having some interesting requirements for the web UI, that (rather surprisingly, one would think) one doesn t usually find advertised in many projects:
  • Straightforward to create and maintain.
  • Well integrated with Django.
  • Easy to package in Debian, with as little vendoring as possible, which helps mitigate supply chain attacks
  • Usable without JavaScript whenever possible, for progressive enhancement rather than core functionality.
The idea is to avoid growing the technical complexity and requirements of the web UI, both server-side and client-side, for functionality that is not needed for this kind of project, with tools that do not fit well in our ecosystem. Also, to limit the complexity of the JavaScript portions that we do develop, we choose to limit our JavaScript browser supports to the main browser versions packaged in Debian Stable, plus recent oldstable. This makes JavaScript easier to write and maintain, and it also makes it less needed, as modern HTML plus modern CSS interfaces can go a long way with less scripting interventions. We recently encoded JavaScript practices and tradeoffs in a JavaScript Practices chapter of Debusine s documentation.

How we use JavaScript From the start we built the UI using Bootstrap, which helps in having responsive layouts that can also work on mobile devices. When we started having large select fields, we introduced Select2 to make interaction more efficient, and which degrades gracefully to working HTML. Both Bootstrap and Select2 are packaged in Debian. Form validation is done server-side by Django, and we do not reimplement it client-side in JavaScript, as we prefer the extra round trip through a form submission to the risk of mismatches between the two validations. In those cases where a UI task is not at all possible without JavaScript, we can make its support mandatory as long as the same goal can be otherwise achieved using the debusine client command.

Django messages as Bootstrap toasts Django has a Messages framework that allows different parts of a view to push messages to the user, and it is useful to signal things like a successful form submission, or warnings on unexpected conditions. Django messages integrate well with Bootstrap toasts, which use a recognisable notification language, are nicely dismissible and do not invade the rest of the page layout. Since toasts require JavaScript to work, we added graceful degradation. to Bootstrap alerts Doing so was surprisingly simple: we handle the toasts as usual, and also render the plain alerts inside a <noscript> tag. This is precisely the intended usage of the <noscript> tag, and it works perfectly: toasts are displayed by JavaScript when it s available, or rendered as alerts when not. The resulting Django template is something like this:
<div aria-live="polite" aria-atomic="true" class="position-relative">
    <div class="toast-container position-absolute top-0 end-0 p-3">
     % for message in messages % 
        <div class="toast" role="alert" aria-live="assertive" aria-atomic="true">
            <div class="toast-header">
                <strong class="me-auto">  message.level_tag capfirst  </strong>
                <button type="button"
                        class="btn-close"
                        data-bs-dismiss="toast"
                        aria-label="Close"></button>
            </div>
            <div class="toast-body">  message  </div>
        </div>
     % endfor % 
    </div>
</div>
<!--   -->
 % if messages % 
<noscript>
     % for message in messages % 
        <div class="alert alert-primary" role="alert">
              message  
        </div>
     % endfor % 
</noscript>
 % endif % 
We have a webpage to test the result.

JavaScript incremental improvement of formsets Debusine is built around workspaces, which are, among other things, containers for resources. Workspaces can inherit from other workspaces, which act as fallback lookups for resources. This allows, for example, to maintain an experimental package to be built on Debian Unstable, without the need to copy the whole Debian Unstable workspace. A workspace can inherit from multiple others, which are looked up in order. When adding UI to configure workspace inheritance, we faced the issue that plain HTML forms do not have a convenient way to perform data entry of an ordered list. We initially built the data entry around Django formsets, which support ordering using an extra integer input field to enter the ordering position. This works, and it s good as a fallback, but we wanted something more appropriate, like dragging and dropping items to reorder them, as the main method of interaction. Our final approach renders the plain formset inside a <noscript> tag, and the JavaScript widget inside a display: none element, which is later shown by JavaScript code. As the workspace inheritance is edited, JavaScript serializes its state into <form type='hidden'> fields that match the structure used by the formset, so that when the form is submitted, the view performs validation and updates the server state as usual without any extra maintenance burden. Serializing state as hidden form fields looks a bit vintage, but it is an effective way of preserving the established data entry protocol between the server and the browser, allowing us to do incremental improvement of the UI while minimizing the maintenance effort.

More to come Debusine is now gaining significant adoption and is still under active development, with new features like personal archives coming soon. This will likely mean more user stories for the UI, so this is a design space that we are going to explore again and again in the coming future. Meanwhile, you can try out Debusine on debusine.debian.net, and follow its development on salsa.debian.org!

11 September 2025

Jonathan Wiltshire: Debian stable updates explained: security, updates, and point releases

Please consider supporting my work in Debian and elsewhere through Liberapay. Debian stable updates work through three main channels: point releases, security repositories, and the updates repository. Understanding these ensures your system stays secure and current.

A note about suite names Every Debian release, or suite, has a codename the most recent major release was trixie, or Debian 13. The codename uniquely identifies that suite. We also use changeable aliases to add meaning to the suite s lifecycle. For example, trixie currently has the alias stable, but when forky becomes stable instead, trixie will become known as oldstable. This post uses either codenames or aliases depending on context. In source lists, codenames are generally preferred since that avoids surprise major upgrades right after a release is made.

The stable suites (point releases) stable and oldstable (currently trixie and bookworm) are only updated during a point release. This is a minor update released to a major version. For example, 13.1 is the first minor update to trixie. It s not possible to install older minor versions of a suite except via the snapshots mechanism (not covered here). It s possible to view past versions via snapshot.debian.org, which preserves historical Debian archives. There are also the testing and unstable aliases for the development suites. However, these are not relevant for users who want to run officially released versions. Almost every stable installation of Debian will be opted into a stable or oldstable base suite. An example APT source might look like:
Type: deb
URIs: http://deb.debian.org/debian
Suites: trixie
Components: main
Signed-By: /usr/share/keyrings/debian-archive-keyring.pgp
Or, in legacy sources.list style:
deb https://deb.debian.org/debian trixie main

The security suites (DSAs explained) For urgent security-related updates, the Security Team maintains a counterpart suite for each stable suite. These are called stable-security and oldstable-security when maintained by Debian s security team, and oldstable-security, oldoldstable-security, etc when maintained by the LTS team. Example APT source:
Type: deb
URIs: https://deb.debian.org/debian-security
Suites: trixie-security
Components: main
Signed-By: /usr/share/keyrings/debian-archive-keyring.pgp
Or, in legacy sources.list style:
deb https://deb.debian.org/debian-security trixie-security main
The Debian installer enables the security suites by default. Debian Security Announcements (DSAs) are published to debian-security-announce@lists.debian.org.

The updates suites (SUAs and maintenance) For urgent non-security updates, the final recommended suites are stable-updates and oldstable-updates. This is where updates staged for a point release, but needed sooner, are published. Examples include virus database updates, timezone changes, urgent bug fixes for specific problems and corrections to errors in the release process itself. Example APT source:
Type: deb
URIs: https://deb.debian.org/debian
Suites: trixie-updates
Components: main
Signed-By: /usr/share/keyrings/debian-archive-keyring.pgp
Or, in legacy sources.list style:
deb https://deb.debian.org/debian trixie-updates main
Debian enables the updates suites by default. Stable Update Announcements (SUAs) are published to debian-stable-announce@lists.debian.org. This is also where announcements of forthcoming point releases are published.

Summary These are the recommended suites for all production Debian systems:
SuiteExample codenamePurposeAnnouncements
stabletrixieBase suite containing all the available software for a release. Point releases every 2 4 months including lower-severity security fixes that do not require immediate release.Debian Release Announcements on debian-announce
stable-securitytrixie-securityUrgent security updates.Debian Security Announcements on debian-security-announce
stable-updatestrixie-updatesUrgent non-security updates, data updates and release maintenance.Stable Update Announcements on debian-stable-announce
After a release moves from oldstable to unsupported status, Long Term Support (LTS) takes over for several more years. LTS provides urgent security updates for selected architectures. For details, see wiki.debian.org/LTS. If you d like to stay informed, the official Debian announcement lists and release.debian.org share the latest schedules and updates.
Photo by Brian Wangenheim on Unsplash

6 September 2025

Antonio Terceiro: autopkgtest support in Debian: a more optimistic view

Yesterday I posted about the history, in numbers, of the support for autopkgtest in the Debian archive. I had analyzed the presence of a Testsuite: field in source packages, from wheezy to trixie, and noticed a slowdown in the growth rate of autopkgtest support, in proportional terms. In each new release, the percentage of packages declaring a test suite grew less than in the previous release, for the last 4 releases. A night of sleep and a rainy morning later, I come back with a more optimistic view, and present to you the following data, expanded from the raw data:
Release year Release Yes No Total Yes No Total
2013 wheezy 5 17170 17175 -- -- --
2015 jessie 1112 19484 20596 1107 2314 3421
2017 stretch 5110 19735 24845 3998 251 4249
2019 buster 9966 18535 28501 4856 -1200 3656
2021 bullseye 13949 16994 30943 3983 -1541 2442
2023 bookworm 17868 16473 34341 3919 -521 3398
2025 trixie 21527 16143 37670 3659 -330 3329
A few observations: All in all, I think this data show that Debian maintainers recognize the usefulness of automated testing and are engaged in improving our QA process.

5 September 2025

Antonio Terceiro: Past halfway there: history of autopkgtest support in Debian

The Release of Debian 13 ("Trixie") last month marked another milestone on the effort to provide automated test support for Debian packages in their installed form. We have achieved the mark of 57% of the source packages in the archive declaring support for autopkgtest.
Release Packages with tests Total number of packages % of packages with tests
wheezy 5 17175 0%
jessie 1112 20596 5%
stretch 5110 24845 20%
buster 9966 28501 34%
bullseye 13949 30943 45%
bookworm 17868 34341 52%
trixie 21527 37670 57%
The code that generated this table is provided at the bottom. The growth rate has been consistently decreasing at each release after stretch. That probably means that the low hanging fruit -- adding support en masse for large numbers of similar packages, such as team-maintained packages for a given programming language -- has been picked, and from now on the work gets slightly harder. Perhaps there is a significant long tail of packages that will never get autopkgtest support. Looking for common prefixes among the packages missing a Testsuite: field gives me us the largest groups of packages missing autopkgtest support:
$ grep-dctrl -v -F Testsuite --regex -s Package -n . trixie   cut -d - -f 1   uniq -c   sort -n  tail -20
     50 apertium
     50 kodi
     51 lomiri
     53 maven
     55 libjs
     57 globus
     66 cl
     67 pd
     72 lua
     79 php
     88 puppet
     91 r
    111 gnome
    124 ruby
    140 ocaml
    152 rust
    178 golang
    341 fonts
    557 python
   1072 haskell
There seems to be a fair amount of Haskell and Python. If someone could figure out a way of testing installed fonts in a meaningful way, this would a be a good niche where we can cover 300+ packages. There is a another analysis that can be made, which I didn't: which percentage of new packages introduced in a given release have declared autopkgtest support, compared with the total of new packages in that release? My data only counts the totals, so we start with the technical debt of the almost all of the 17,000 packages with no tests in wheezy, which was the stable at the time I started Debian CI. How many of those got tests since then? Note that not supporting autopkgtest does not mean that a package is not tested at all: it can run build-time tests, which are also useful. Not supporting autopkgtest, though, means that their binaries in the archive can't be automatically tested in their installed, but then there is a entire horde of volunteers running testing and unstable on a daily basis who test Debian and report bugs. This is the script that produced the table in the beginning of this post:
#!/bin/sh
set -eu
extract()  
  local release
  local url
  release="$1"
  url="$2"
  if [ ! -f "$ release " ]; then
    rm -f "$ release .gz"
    curl --silent -o $ release .gz "$ url "
    gunzip "$ release .gz"
  fi
  local with_tests
  local total
  with_tests="$(grep-dctrl -c -F Testsuite --regex . $release)"
  total="$(grep-dctrl -c -F Package --regex . $release)"
  echo "  $ release    $ with_tests    $ total    $((100*with_tests/total))%  "
 
echo "  **Release**   **Packages with tests**   **Total number of packages**   **% of packages with tests**  "
echo " ------------- ------------------------- ------------------------------ ------------------------------ "
for release in wheezy jessie stretch buster; do
  extract "$ release " "http://archive.debian.org/debian/dists/$ release /main/source/Sources.gz"
done
for release in bullseye bookworm trixie; do
  extract "$ release " "http://ftp.br.debian.org/debian/dists/$ release /main/source/Sources.gz"
done

1 September 2025

Russ Allbery: Review: Regenesis

Review: Regenesis, by C.J. Cherryh
Series: Cyteen #2
Publisher: DAW
Copyright: January 2009
ISBN: 0-7564-0592-0
Format: Mass market
Pages: 682
The main text below is an edited version of my original review of Regensis written on 2012-12-21. Additional comments from my re-read are after the original review. Regenesis is a direct sequel to Cyteen, picking up very shortly after the end of that book and featuring all of the same characters. It would be absolutely pointless to read this book without first reading Cyteen; all of the emotional resonance and world-building that make Regensis work are done there, and you will almost certainly know whether you want to read it after reading the first book. Besides, Cyteen is one of the best SF novels ever written and not the novel to skip. Because this is such a direct sequel, it's impossible to provide a good description of Regenesis without spoiling at least characters and general plot developments from Cyteen. So stop reading here if you've not yet read the previous book. I've had this book for a while, and re-read Cyteen in anticipation of reading it, but I've been nervous about it. One of the best parts of Cyteen is that Cherryh didn't belabor the ending, and I wasn't sure what part of the plot could be reasonably extended. Making me more nervous was the back-cover text that framed the novel as an investigation of who actually killed the first Ari, a question that was fairly firmly in the past by the end of Cyteen and that neither I nor the characters had much interest in answering. Cyteen was also a magical blend of sympathetic characters, taut tension, complex plotting, and wonderful catharsis, the sort of lightning in a bottle that can rarely be caught twice. I need not have worried. If someone had told me that Regenesis was another 700 pages of my favorite section of Cyteen, I would have been dubious. But that's exactly what it is. And the characters only care about Ari's murderer because it comes up, fairly late in the novel, as a clue in another problem. Ari and Justin are back in the safe laboratory environment of Reseune, safe now that politics are not trying to kill or control them. Yanni has taken over administration. There is a general truce, and even some deeper agreement. Everyone can take a breath and relax, albeit with the presence of Justin's father Jordan as an ongoing irritant. But broader Union politics are not stable: there is an election in progress for the Defense councilor that may break the tenuous majority in favor of Reseune and the Science Directorate, and Yanni is working out a compromise to gain more support by turning a terraforming project loose on a remote world. As the election and the politics heat up, interpersonal relationships abruptly deteriorate, tensions with Jordan sharply worsen, and there may be moles in Reseune's iron-clad security. Navigating the crisis while keeping her chosen family safe will once again tax all of Ari's abilities. The third section of Cyteen, where Ari finally has the tools to take fate into her own hands and starts playing everyone off against each other, is one of my favorite sections of any book. If it was yours as well, Regenesis is another 700 pages of exactly that. As an extension and revisiting, it does lose a bit of immediacy and surprise from the original. Regenesis is also less concerned with the larger questions of azi society, the nature of thought and personality, loyalty and authority, and the best model for the development of human civilization. It's more of a political thriller. But it's a political thriller that recaptures much of the drama and tension of Cyteen and is full of exceptionally smart and paranoid people thinking through all angles of a problem, working fast on their feet, and successfully navigating tricky and treacherous political landscapes. And, like Cyteen but unlike others of Cherryh's novels I've read, it's a novel about empowerment, about seizing control of one's surroundings and effectively using all of the capability and leverage at one's fingertips. That gives it a catharsis that's almost as good as Cyteen. It's also, like its predecessor, a surprisingly authoritarian novel. I think it's in that, more than anything else in these books, that one sees the impact of the azi. Regenesis makes it clear that the story is set, not in a typical society, but inside a sort of corporation, with an essentially hierarchical governance structure. There are other SF novels set within corporations (Solitaire comes to mind), but normally they follow peons or at best mid-level personnel or field agents, or otherwise take the viewpoint of the employees or the exploited. When they follow the corporate leaders, the focus usually isn't down inside the organization, but out into the world, with the corporation as silent resources on which the protagonist can draw. Regenesis is instead about the leadership. It's about decisions about the future of humanity that characters feel they can make undemocratically (in part because they or their predecessors have effectively engineered the opinions of the democratic population), but it's also about how one manages and secures a top-down organization. Reseune is, as in the previous novel, a paranoid's suspicions come true; everyone is out to get everyone else, or at least might be, and the level of omnipresent security and threat forces a close parsing of alliances and motivations that elevates loyalty to the greatest virtue. In Cyteen, we had long enough with Ari to see the basic shape of her personality and her slight divergences from her predecessor, but her actions are mostly driven by necessity. Regenesis gives us more of a picture of what she's like when her actions aren't forced, and here I think Cherryh manages a masterpiece of subtle characterization. Ari has diverged substantially from her predecessor without always realizing, and those divergences are firmly grounded in the differences she found or created between her life and the first Ari's. She has friends, confidents, and a community, which combined with past trauma has made her fiercely, powerfully protective. It's that protective instinct that weaves the plot together. So many of the events of Cyteen and Regenesis are driven by people's varying reactions to trauma. If you, like me, loved the last third of Cyteen, read this, because Regenesis is more of exactly that. Cherryh finds new politics, new challenges, and a new and original plot within the same world and with the same characters, but it has the same feel of maneuvering, analysis, and decisive action. You will, as with Cyteen have to be comfortable with pages of internal monologue from people thinking through all sides of a problem. If you didn't like that in the previous book, avoid this one; if you loved it, here's the sequel you didn't know you were waiting for. Original rating: 9 out of 10

Some additional thoughts after re-reading Regenesis in 2025: Cyteen mostly held up to a re-reading and I had fond memories of Regenesis and hoped that it would as well. Unfortunately, it did not. I think I can see the shape of what I enjoyed the first time I read it, but I apparently was in precisely the right mood for this specific type of political power fantasy. I did at least say that you have to be comfortable with pages of internal monologue, but on re-reading, there was considerably more of that than I remembered and it was quite repetitive. Ari spends most of the book chasing her tail, going over and around and beside the same theories that she'd already considered and worrying over the nuances of every position. The last time around, I clearly enjoyed that; this time, I found it exhausting and not very well-written. The political maneuvering is not that deep; Ari just shows every minutia of her analysis. Regenesis also has more about the big questions of how to design a society and the role of the azi than I had remembered, but I'm not sure those discussions reach any satisfying conclusions. The book puts a great deal of effort into trying to convince the reader that Ari is capable of designing sociological structures that will shape Union society for generations to come through, mostly, manipulation of azi programming (deep sets is the term used in the book). I didn't find this entirely convincing the first time around, and I was even less convinced in this re-read. Human societies are a wicked problem, and I don't find Cherryh's computer projections any more convincing than Asimov's psychohistory. Related, I am surprised, in retrospect, that the authoritarian underpinnings of this book didn't bother me more on my first read. They were blatantly obvious on the second read. This felt like something Cherryh put into these books intentionally, and I think it's left intentionally ambiguous whether the reader is supposed to agree with Ari's goals and decisions, but I was much less in the mood on this re-read to read about Ari making blatantly authoritarian decisions about the future of society simply because she's smart and thinks she, unlike others, is acting ethically. I say this even though I like Ari and mostly enjoyed spending time in her head. But there is a deep fantasy of being able to reprogram society at play here that looks a lot nastier from the perspective of 2025 than apparently it did to me in 2012. Florian and Catlin are still my favorite characters in the series, though. I find it oddly satisfying to read about truly competent bodyguards, although like all of the azi they sit in an (I think intentionally) disturbing space of ambiguity between androids and human slaves. The somewhat too frank sexuality from Cyteen is still present in Regenesis, but I found it a bit less off-putting, mostly because everyone is older. The authoritarian bent is stronger, since Regenesis is the story of Ari consolidating power rather than the underdog power struggle of Cyteen, and I had less tolerance for it on this re-read. The main problem with this book on re-read was that I bogged down about halfway through and found excuses to do other things rather than finish it. On the first read, I was apparently in precisely the right mood to read about Ari building a fortified home for all of her friends; this time, it felt like endless logistics and musings on interior decorating that didn't advance the plot. Similarly, Justin and Grant's slow absorption into Ari's orbit felt like a satisfying slow burn friendship in my previous reading and this time felt touchy and repetitive. I was one of the few avid defenders of Regenesis the first time I read it, and sadly I've joined the general reaction on a re-read: This is not a very good book. It's too long, chases its own tail a bit too much, introduces a lot more authoritarianism and doesn't question it as directly as I wanted, and gets even deeper into Cherryh's invented pseudo-psychology than Cyteen. I have a high tolerance for the endless discussions of azi deep sets and human flux thinking, and even I got bored this time through. On re-read, this book was nowhere near as good as I thought it was originally, and I would only recommend it to people who loved Cyteen and who really wanted a continuation of Ari's story, even if it is flabby and not as well-written. I have normally been keeping the rating of my first read of books, but I went back and lowered this one by two points to ensure it didn't show as high on my list of recommendations.

Re-read rating: 6 out of 10

31 August 2025

Otto Kek l inen: Managing procrastination and distractions

Featured image of post Managing procrastination and distractionsI ve noticed that procrastination and inability to be consistently productive at work has become quite common in recent years. This is clearly visible in younger people who have grown up with an endless stream of entertainment literally at their fingertips, on their mobile phone. It is however a trap one can escape from with a little bit of help. Procrastination is natural they say humans are lazy by nature after all. Probably all of us have had moments when we choose to postpone a task we know we should be working on, and instead spent our time doing secondary tasks (valorisation). Classic example is cleaning your apartment when you should be preparing for an exam. Some may procrastinate by not doing any work at all, and just watching YouTube videos or the like. To some people, typically those who are in their 20s and early in their career, procrastination can be a big challenge and finding the discipline to stick to planned work may need intentional extra effort, and perhaps even external help. During my 20+ year career in software development I ve been blessed to work with engineers of various backgrounds and each with their unique set of strengths. I have also helped many grow in various areas and overcome challenges, such as lack of intrinsic motivation and managing procrastination, and some might be able to get it in check with some simple advice.

Distance yourself from the digital distractions The key to avoiding distractions and procrastination is to make it inconvenient enough that you rarely do it. If continuing to do work is easier than switching to procrastination, work is more likely to continue. Tips to minimize digital distractions, listed in order of importance:
  1. Put your phone away. Just like when you go to a movie and turn off your phone for two hours, you can put the phone away completely when starting to work. Put the phone in a different room to ensure there is enough physical distance between you and the distraction, so it is impossible for you to just take a quick peek .
  2. Turn off notifications from apps. Don t let the apps call you like sirens luring Odysseus. You don t need to have all the notifications. You will see what the apps have when you eventually open them at a time you choose to use them.
  3. Remove or disable social media apps, games and the like from your phone and your computer. You can install them back when you have vacation. You can probably live without them for some time. If you can t remove them, explore your phone s screen time restriction features to limit your own access to apps that most often waste your time. These features are sometimes listed in the phone settings under digital health .
  4. Have a separate work computer and work phone. Having dedicated ones just for work that are void of all unnecessary temptations helps keep distance from the devices that could derail your focus.
  5. Listen to music. If you feel your brain needs a dose of dopamine to get you going, listening to music helps satisfy your brain s cravings while still being able to simultaneously keep working.
Doing a full digital detox is probably not practical, or not sustainable for an extended time. One needs apps to stay in touch with friends and family, and staying current in software development probably requires spending some time reading news online and such. However the tips above can help contain the distractions and minimize the spontaneous attention the distractions get. Some of the distractions may ironically be from the work itself, for example Slack notifications or new email notifications. I recommend turning them off for a couple of hours every day to have some distraction free time. It should be enough to check work mail a couple times a day. Checking them every hour probably does not add much overall value for the company unless your work is in sales or support where the main task itself is responding to emails.

Distraction free work environment Following the same principle of distancing yourself from distractions, try to use a dedicated physical space for working. If you don t have a spare room to dedicate to work, use a neighborhood caf or sign up for a local co-working space or start commuting to the company office to find a space to be focused on work in.

Break down tasks into smaller steps Sometimes people postpone tasks because they feel intimidated by the size or complexity of a task. In particular in software engineering problems may be vague and appear large until one reaches the breakthrough that brings the vision of how to tackle it. Breaking down problems into smaller more manageable pieces has many advantages in software engineering. Not only can it help with task-avoidance, but it can also make the problem easier to analyze, suggest solutions and test them and build a solid foundation to expand upon to ultimately later reach a full solution on the entire larger problem. Working on big problems as a chain of smaller tasks may also offer more opportunities to celebrate success on completing each subtask and help getting in a suitable cadence of solving a single thing, taking a break and then tackling the next issue. Breaking down a task into concrete steps may also help with getting more realistic time estimations. Sometimes procrastination isn t real someone could just be overly ambitious and feel bad about themselves for not doing an unrealistic amount of work.

Intrinsic motivation Of course, you should follow your passion when possible. Strive to pick a career that you enjoy, and thus maximize the intrinsic motivation you experience. However, even a dream job is still a job. Nobody is ever paid to do whatever they want. Any work will include at least some tasks that feel like a chore or otherwise like something you would not do unless paid to. Some would say that the definition of work itself is having to do things one would otherwise not do. You can only fully do whatever you want while on vacation or when you choose to not have a job at all. But if you have a job, you simply need to find the intrinsic motivation to do it. Simply put, some tasks are just unpleasant or boring. Our natural inclination is to avoid them in favor of more enjoyable activities. For these situations we just have to find the discipline to force ourselves to do the tasks and figuratively speaking whip ourselves into being motivated to complete the tasks.

Extrinsic motivation As the name implies, this is something people external to you need to provide, such as your employer or manager. If you have challenges in managing yourself and delivering results on a regular basis, somebody else needs to set goals and deadlines and keep you accountable for them. At the end of the day this means that eventually you will stop receiving salary or other payments unless you did your job. Forcing people to do something isn t nice, but eventually it needs to be done. It would not be fair for an employer to pay those who did their work the same salary as those who procrastinated and fell short on their tasks. If you work solo, you can also simulate the extrinsic motivation by publicly announcing milestones and deadlines to build up pressure for yourself to meet them and avoid publicly humiliation. It is a well-studied and scientifically proven phenomenon that most university students procrastinate at the start of assignments, and truly start working on them only once the deadline is imminent.

External help for addictions If procrastination is mainly due to a single distraction that is always on your mind, it may be a sign of an addiction. For example, constantly thinking about a computer game or staying up late playing a computer game, to the extent that it seriously affects your ability to work, may be a symptom of an addiction, and getting out of it may be easier with external help.

Discipline and structure Most of the time procrastination is not due to an addiction, but simply due to lack of self-discipline and structure. The good thing is that those things can be learned. It is mostly a matter of getting into new habits, which most young software engineers pick up more or less automatically while working along the more senior ones. Hopefully these tips can help you stay on track and ensure you do everything you are expected to do with clear focus, and on time!

28 August 2025

Valhalla's Things: 1840s Underwear

Posted on August 28, 2025
Tags: madeof:atoms, craft:sewing, FreeSoftWear
A woman wearing a knee-length shift with very short pleated sleeves and drawers that are a bit longer than needed to be ankle-length. The shift is too wide at the top, had to have a pleat taken in the center front, but the sleeves are still falling down. She is also wearing a black long sleeved t-shirt and leggings under said underwear, for decency. A bit more than a year ago, I had been thinking about making myself a cartridge pleated skirt. For a number of reasons, one of which is the historybounding potential, I ve been thinking pre-crinoline, so somewhere around the 1840s, and that s a completely new era for me, which means: new underwear. Also, the 1840s are pre-sewing machine, and I was already in a position where I had more chances to handsew than to machine sew, so I decided to embrace the slowness and sew 100% by hand, not even using the machine for straight seams. A woman turning fast enough that her petticoat extends a considerable distance from the body. The petticoat is white with a pattern of cording from the hem to just below hip level, with a decreasing number of rows of cording going up. If I remember correctly, I started with the corded petticoat, looking around the internet for instructions, and then designing my own based on the practicality of using modern wide fabric from my stash (and specifically some DITTE from costumers favourite source of dirty cheap cotton IKEA). Around the same time I had also acquired a sashiko kit, and I used the Japanese technique for sewing running stitches pushing the needle with a thimble that covers the base of the middle finger, and I can confirm that for this kind of things it s great! I ve since worn the petticoat a few times for casual / historyBounding / folkwearBounding reasons, during the summer, and I can confirm it s comfortable to use; I guess that during the winter it could be nice to add a flannel layer below it. The technical drawing and pattern for drawers from the book: each leg is cut out of a rectangle of fabric folded along the length, the leg is tapered equally, while the front is tapered more than the back, and comes to a point below the top of the original rectangle. Then I proceeded with the base layers: I had been browsing through The workwoman's guide and that provided plenty of examples, and I selected the basic ankle-length drawers from page 53 and the alternative shift on page 47. As for fabric, I had (and still have) a significant lack of underwear linen in my stash, but I had plenty of cotton voile that I had not used in a while: not very historically accurate for plain underwear, but quite suitable for a wearable mockup. Working with a 1830s source had an interesting aspect: other of the usual, mildly annoying, imperial units, it also used a lot a few obsolete units, especially nails, that my qalc, my usual calculator and converter, doesn t support. Not a big deal, because GNU units came to the rescue, and that one knows a lot of obscure and niche units, and it s quite easy to add those that are missing1 Working on this project also made me freshly aware of something I had already noticed: converting instructions for machine sewing garments into instructions for hand sewing them is usually straightforward, but the reverse is not always true. Starting from machine stitching, you can usually convert straight stitches into backstitches (or running backstitches), zigzag and overlocking into overcasting and get good results. In some cases you may want to use specialist hand stitches that don t really have a machine equivalent, such as buttonhole stitches instead of simply overcasting the buttonhole, but that s it. Starting from hand stitching, instead, there are a number of techniques that could be converted to machine stitching, but involve a lot of visible topstitching that wasn t there in the original instructions, or at times are almost impossible to do by machine, if they involve whipstitching together finished panels on seams that are subject to strong tension. Anyway, halfway through working with the petticoat I cut both the petticoat and the drawers at the same time, for efficiency in fabric use, and then started sewing the drawers. the top third or so of the drawers, showing a deep waistband that is closed with just one button at the top, and the front opening with finished edges that continue through the whole crotch, with just the overlap of fabric to provide coverage. The book only provided measurements for one size (moderate), and my fabric was a bit too narrow to make them that size (not that I have any idea what hip circumference a person of moderate size was supposed to have), so the result is just wide enough to be comfortably worn, but I think that when I ll make another pair I ll try to make them a bit wider. On the other hand they are a bit too long, but I think that I ll fix it by adding a tuck or two. Not a big deal, anyway. The same woman as in the opening image from the back, the shift droops significantly in the center back, and the shoulder straps have fallen down on the top of the arms. The shift gave me a bit more issues: I used the recommended gusset size, and ended up with a shift that was way too wide at the top, so I had to take a box pleat in the center front and back, which changed the look and wear of the garment. I have adjusted the instructions to make gussets wider, and in the future I ll make another shift following those. Even with the pleat, the narrow shoulder straps are set quite far to the sides, and they tend to droop, and I suspect that this is to be expected from the way this garment is made. The fact that there are buttonholes on the shoulder straps to attach to the corset straps and prevent the issue is probably a hint that this behaviour was to be expected. The technical drawing of the shift from the book, showing a the top of the body, two trapezoidal shoulder straps, the pleated sleeves and a ruffle on the front edge. I ve also updated the instructions so that they shoulder straps are a bit wider, to look more like the ones in the drawing from the book. Making a corset suitable for the time period is something that I will probably do, but not in the immediate future, but even just wearing the shift under a later midbust corset with no shoulder strap helps. I m also not sure what the point of the bosom gores is, as they don t really give more room to the bust where it s needed, but to the high bust where it s counterproductive. I also couldn t find images of original examples made from this pattern to see if they were actually used, so in my next make I may just skip them. Sleeve detail, showing box pleats that are about 2 cm wide and a few mm distance from each other all along the circumference, neatly sewn into the shoulder strap on one side and the band at the other side. On the other hand, I m really happy with how cute the short sleeves look, and if2 I ll ever make the other cut of shift from the same book, with the front flaps, I ll definitely use these pleated sleeves rather than the straight ones that were also used at the time. As usual, all of the patterns have been published on my website under a Free license:

  1. My ~/.units file currently contains definitions for beardseconds, bananas and the more conventional Nm and NeL (linear mass density of fibres).
  2. yeah, right. when.

27 August 2025

Matthew Palmer: StrongBox: Simple, Safe Data Encryption for Rust

Some time ago, I wanted to encrypt a bunch of data in an application I was writing in Rust, mostly to be stored in a database, but also session cookies and sensitive configuration variables. Since Rust is widely known as a secure-yet-high-performance programming language, I was expecting that there would be a widely-used crate that gave me a secure, high-level interface to strong, safe cryptography. Imagine my surprise when I discovered that just didn t seem to exist. Don t get me wrong: Rust is replete with fast, secure, battle-tested cryptographic primitives. The RustCrypto group provides all manner of robust, widely-used crates for all manner of cryptography-related purposes. They re the essential building blocks for practical cryptosystems, but using them directly in an application is somewhat akin to building a car from individual atoms of iron and carbon. So I wrote my own high-level data encryption library, called it StrongBox, and have been happily encrypting and decrypting data ever since.

Cryptography So Simple Even I Can t Get It Wrong The core of StrongBox is the StrongBox trait, which has only two methods: encrypt and decrypt, each of which takes just two arguments. The first argument is the plaintext (for encrypt) or the ciphertext (for decrypt) to work on. The second argument is the encryption context, for use as Authenticated Additional Data, an important part of many uses of encryption. There s essentially no configuration or parameters to get wrong. You can t choose the encryption algorithm, or block cipher mode, and you don t have to worry about generating a secure nonce. You create a StrongBox with a key, and then you call encrypt and decrypt. That s it.

Practical Cryptographic Affordances Ok, ok that s not quite it. Because StrongBox is even easier to use than what I ve described, thanks to the companion crate, StructBox. When I started using StrongBox in the wild , it quickly became clear that what I almost always wanted to encrypt in my application wasn t some ethereal plaintext . I wanted to encrypt things, specifically structs (and enums). So, through the magic of Rust derive macros, I built StructBox, which provides encrypt and decrypt operations on any Serde-able type. Given that using Serde encoders can be a bit fiddly to use, it s virtually easier to get an encrypted, serialized struct than it is to get a plaintext serialized struct.

Key Problems in Cryptography The thing about cryptography is that it largely turns all data security problems into key management problems. All the fancy cryptographic wonkery is for naught if you don t manage the encryption keys well. So, most of the fancy business in StrongBox isn t the encryption and decryption, but instead solving problems around key management.

Different Keys for Different Purposes Using the same key for all of your cryptographic needs is generally considered a really bad idea. It opens up all manner of risks, that are easily avoided if you use different keys for different things. However, having to maintain a big pile of different keys is a nightmare, so nobody s going to do that. Enter: key derivation. Create one safe, secure root key, and then use a key derivation function to spawn as many other keys as you need. Different keys for each database column, another one to encrypt cookies, and so on. StrongBox supports this through the StemStrongBox type. You ll typically start off by creating a StemStrongBox with the root key, and then derive whatever other StrongBoxes you need, for encrypting and decrypting different kinds of data.

You Spin Me Round Sometimes, keys need to be rotated. Whether that s because you actually know (or even have reason to suspect) someone has gotten the key, or just because you re being appropriately paranoid, sometimes key rotation has to happen. As someone who has had to rotate keys in situations where such an eventuality was not planned for, I can say with some degree of authority: it absolutely sucks to have to do an emergency key rotation in a system that isn t built to make that easy. That s why StrongBox natively supports key rotation. Every StrongBox takes one encryption key, and an arbitrary number of decryption keys, and will automatically use the correct key to decrypt ciphertexts.

Will You Still Decrypt Me, Tomorrow? In addition to manual key rotation, StrongBox also supports time-based key rotation with the RotatingStrongBox type. This comes in handy when you re encrypting a lot of ephemeral data, like cookies (or server-side session data). It provides a way to automatically expire old data, and prevents attacks that become practical when large amounts of data are encrypted using a single key.

Invasion of the Invisible Salamanders! I mostly mention this just because I love the name, but there is a kind of attack possible in common AEAD modes called the invisible salamanders attack. StrongBox implements mitigations against this, by committing to the key being used so that an attacker can t forge a ciphertext that decrypts validly to different plaintexts when using different keys. This is why I love cryptography: everything sounds like absolute goddamn magic.

Call Me Crazy, Support Me Maybe? If you re coding in Rust (which you probably should be), encrypting your stored data (which you definitely should be), and StrongBox makes your life easier (which it really will), you can show your appreciation for my work by contributing to my open source code-fund. Simply by shouting me a refreshing beverage, you ll be helping me out, and helping to grow the software commons. Alternately, if you re looking for someone to Speak Rust to Computers on a professional basis, I m available for contracts or full-time remote positions.

17 August 2025

C.J. Collier: The Very Model of a Patriot Online

It appears that the fragile masculinity tech evangelists have identified Debian as a community with boundaries which exclude them from abusing its members and they re so angry about it! In response to posts such as this, and inspired by Dr. Conway s piece, I ve composed a poem which, hopefully, correctly addresses the feelings of that crowd.
The Very Model of a Patriot Online
I am the very model of a modern patriot online,
My keyboard is my rifle and my noble cause is so divine.
I didn't learn my knowledge in a dusty college lecture hall,
But from the chans where bitter anonymity enthralls us all.
I spend a dozen hours every day upon my sacred quest,
To put the globo-homo narrative completely to the test.
My arguments are peer-reviewed by fellas in the comments section,
Which proves my every thesis is the model of complete perfection.
I m steeped in righteous anger that the libs call 'white fragility,'
For mocking their new pronouns and their lack of masculinity.
I m master of the epic troll, the comeback, and the searing snark,
A digital guerrilla who is fighting battles in the dark.
I know the secret symbols and the dog-whistles historical,
From Pepe the Frog to  Let s Go Brandon,  in order categorical;
In short, for fighting culture wars with rhetoric rhetorical,
I am the very model of a patriot polemical.
***
I stand for true expression, for the comics and the edgy clown,
Whose satire is too based for all the fragile folks in town.
They say my speech is 'violence' while my spirit they are trampling,
The way they try to silence me is really quite a startling sampling
Of 1984, which I've not read but thoroughly understand,
Is all about the tyranny that's gripping this once-blessed land.
My humor is a weapon, it s a razor-bladed, sharp critique,
(Though sensitive elites will call my masterpiece a form of  hate speech ).
They cannot comprehend my need for freedom from all consequence,
They call it 'hate,' I call it 'jokes,' they just don't have a lick of sense.
So when they call me  bigot  for the spicy memes I post pro bono,
I tell them their the ones who're cancelled, I'm the victim here, you know!
Then I can write a screed against the globalist cabal, you see,
And tell you every detail of their vile conspiracy.
In short, when I use logic that is flexible and personal,
I am the very model of a patriot controversial.
***
I'm very well acquainted with the scientific method, too,
It's watching lengthy YouTube vids until my face is turning blue.
I trust the heartfelt testimony of a tearful, blonde ex-nurse,
But what a paid fact-checker says has no effect and is perverse.
A PhD is proof that you've been brainwashed by the leftist mob,
While my own research on a meme is how I really do my job.
I know that masks will suffocate and vaccines are a devil's brew,
I learned it from a podcast host who used to sell brain-boosting goo.
He scorns the lamestream media, the CNNs and all the rest,
Whose biased reporting I've put fully to a rigorous test
By only reading headlines and confirming what I already knew,
Then posting my analysis for other patriots to view.
With every "study" that they cite from sources I can't stand to hear,
My own profound conclusions become ever more precisely clear.
In short, when I've debunked the experts with a confident "Says who?!",
I am the very model of a researcher who sees right through you.
***
But all these culture wars are just a sleight-of-hand, a clever feint,
To hide the stolen ballots and to cover up the moral taint
Of D.C. pizza parlors and of shipping crates from Wayfair, it s true,
It's all connected in a plot against the likes of me and you!
I've analyzed the satellite photography and watermarks,
I understand the secret drops, the cryptic Qs, the coded sparks.
The  habbening  is coming, friends, just give it two more weeks or three,
When all the traitors face the trials for their wicked treachery.
They say that nothing happened and the dates have all gone past, you see,
But that's just disinformation from the globalist enemy!
Their moving goalposts constantly, a tactic that is plain to see,
To wear us down and make us doubt the coming, final victory!
My mind can see the patterns that a simple sheep could never find,
The hidden puppet-masters who are poisoning our heart and mind.
In short, when I link drag queens to the price of gas and child-trafficking,
I am the very model of a patriot whose brain is quickening!
***
My pickup truck's a testament to everything that I hold dear,
With vinyl decals saying things the liberals all hate and fear.
The Gadsden flag is waving next to one that's blue and starkly thin,
To show my deep respect for law, except the feds who're steeped in sin.
There's Punisher and Molon Labe, so that everybody knows
I'm not someone to trifle with when push to final shoving goes.
I've got my tactical assault gear sitting ready in the den,
Awaiting for the signal to restore our land with my fellow men.
I practice clearing rooms at home when my mom goes out to the store,
A modern Minuteman who's ready for a civil war.
The neighbors give me funny looks, I see them whisper and take note,
They'll see what's what when I'm the one who's guarding checkpoints by their throat.
I am a peaceful man, of course, but I am also pre-prepared,
To neutralize the threats of which the average citizen's unscared.
In short, when my whole identity's a brand of tactical accessory,
You'll say a better warrior has never graced a Cabela's registry.
***
They say I have to tolerate a man who thinks he is a dame,
While feminists and immigrants are putting out my vital flame!
There taking all the jobs from us and giving them to folks who kneel,
And "woke HR" says my best jokes are things I'm not allowed to feel!
An Alpha Male is what I am, a lion, though I'm in this cubicle,
My life's frustrations can be traced to policies Talmudical.
They lecture me on privilege, I, who have to pay my bills and rent!
While they give handouts to the lazy, worthless, and incompetent!
My grandad fought the Nazis! Now I have to press a key for  one 
To get a call-rep I can't understand beneath the blazing sun
Of global, corporate tyranny that's crushing out the very soul
Of men like me, who've lost their rightful, natural, and just control!
So yes, I am resentful! And I'm angry! And I'm right to be!
They've stolen all my heritage and my masculinity!
In short, when my own failures are somebody else's evil plot,
I am the very model of the truest patriot we've got!
***
There putting chips inside of you! Their spraying things up in the sky!
They want to make you EAT THE BUGS and watch your very spirit die!
The towers for the 5G are a mind-control delivery tool!
To keep you docile while the children suffer in a grooming school!
The WEF, and Gates, and Soros have a plan they call the 'Great Reset,'
You'll own no property and you'll be happy, or you'll be in debt
To social credit overlords who'll track your every single deed!
There sterilizing you with plastics that they've hidden in the feed!
The world is flat! The moon is fake! The dinosaurs were just a lie!
And every major tragedy's a hoax with actors paid to cry!
I'M NOT INSANE! I SEE THE TRUTH! MY EYES ARE OPEN! CAN'T YOU SEE?!
YOU'RE ALL ASLEEP! YOU'RE COWARDS! YOU'RE AFRAID OF BEING TRULY FREE!
My heart is beating faster now, my breath is short, my vision's blurred,
From all the shocking truth that's in each single, solitary word!
I've sacrificed my life and friends to bring this message to the light, so...
You'd better listen to me now with all your concentrated might, ho!
***
For my heroic struggle, though it's cosmic and it's biblical,
Is waged inside the comments of a post that's algorithm-ical.
And still for all my knowledge that's both tactical and practical,
My mom just wants the rent I owe and says I'm being dramatical.

Valhalla's Things: rrdtool and Trixie

Posted on August 17, 2025
Tags: madeof:bits
TL;DL: if you re using rrdtool on a 32 bit architecture like armhf make an XML dump of your RRD files just before upgrading to Debian Trixie. I am an old person at heart, so the sensor data from my home monitoring system1 doesn t go to one of those newfangled javascript-heavy data visualization platforms, but into good old RRD files, using rrdtool to generate various graphs. This happens on the home server, which is an armhf single board computer2, hosting a few containers3. So, yesterday I started upgrading one of the containers to Trixie, and luckily I started from the one with the RRD, because when I rebooted into the fresh system and checked the relevant service I found it stopped on ERROR: '<file>' is too small (should be <size> bytes). Some searxing later, I ve4 found this was caused by the 64-bit time_t transition, which changed the format of the files, and that (somewhat unexpectedly) there was no way to fix it on the machine itself. What needed to be done instead was to export the data on an XML dump before the upgrade, and then import it back afterwards. Easy enough, right? If you know about it, which is why I m blogging this, so that other people will know in advance :) Anyway, luckily I still had the other containers on bookworm, so I copied the files over there, did the upgrade, and my home monitoring system is happily running as before.

  1. of course one has a self-built home monitoring system, right?
  2. an A20-OLinuXino-MICRO, if anybody wants to know.
  3. mostly for ease of migrating things between different hardware, rather than insulation, since everything comes from Debian packages anyway.
  4. and by I I really mean Diego, as I was still into denial / distractions mode.

9 August 2025

Thorsten Alteholz: My Debian Activities in July 2025

Debian LTS This was my hundred-thirty-third month that I did some work for the Debian LTS initiative, started by Raphael Hertzog at Freexian. During my allocated time I uploaded or worked on: I also continued my work on suricata, which turned out to be more challenging than expected. This month I also did a week of FD duties and attended the monthly LTS/ELTS meeting. Debian ELTS This month was the eighty-fourth ELTS month. Unfortunately my allocated hours were far less than expected, so I couldn t do as much work as planned. Most of the time I spent with FD tasks and I also attended the monthly LTS/ELTS meeting. I further listened to the debusine talks during debconf. On the one hand I would like to use debusine to prepare uploads for embargoed ELTS issues, on the other hand I would like to use debusine to run the version of lintian that is used in the different releases. At the moment some manual steps are involved here and I tried to automate things. Of course like for LTS, I also continued my work on suricata. Debian Printing This month I uploaded a new upstream version of: Guess what, I also started to work on a new version of hplip and intend to upload it in August. This work is generously funded by Freexian! Debian Astro This month I uploaded new upstream versions of: I also uploaded the new package boinor. This is a fork of poliastro, which was retired by upstream and removed from Debian some months ago. I adopted it and rebranded it at the desire of upstream. boinor is the abbreviation of BOdies IN ORbit and I hope this software is still useful. Debian Mobcom Unfortunately I didn t found any time to work on this topic. misc On my fight against outdated RFPs, I closed 31 of them in July. Their number is down to 3447 (how can you dare to open new RFPs? :-)). Don t be afraid of them, they don t bite and are happy to be released to a closed state. FTP master The peace will soon come to an end, so this month I accepted 87 and rejected 2 packages. The overall number of packages that got accepted was 100.

6 August 2025

David Bremner: Using git-annex for email and notmuch metadata

Introducing git-remote-notmuch Based on an idea and ruby implementation by Felipe Contreras, I have been developing a git remote helper for notmuch. I will soon post an updated version of the patchset to the notmuch mailing list (I wanted to refer to this post in my email). In this blog post I'll outline my experiments with using that tool, along with git-annex to store (and sync) a moderate sized email store along with its notmuch metadata.

WARNING The rest of this post describes some relatively complex operations using (at best) alpha level software (namely git-remote-notmuch). git-annex is good at not losing your files, but git-remote-notmuch can (and did several times during debugging) wipe out your notmuch database. If you have a backup (e.g. made with notmuch-dump), this is much less annoying, and in particular you can decide to walk away from this whole experiment and restore your database.

Why git-annex? I currently have about 31GiB of email, spread across more than 830,000 files. I want to maintain the ability to search and read my email offline, so I need to maintain a copy on several workstations and at least one server (which is backed up explicitly). I am somewhat commited to maintaining synchronization of tags to git since that is how the notmuch bug tracker works. Commiting the email files to git seems a bit wasteful: by design notmuch does not modify email files, and even with compression, the extra copy adds a fair amount of overhead (in my case, 17G of git objects, about 57% overhead). It is also notoriously difficult to completely delete files from a git repository. git-annex offers potential mitigation for these two issues, at the cost of a somewhat more complex mental model. The main idea is that instead of committing every version of a file to the git repository, git-annex tracks the filename and metadata, with the file content being stored in a key-value store outside git. Conceptually this is similar to git-lfs. From our current point, the important point is that instead of a second (compressed) copy of the file, we store one copy, along with a symlink and a couple of directory entries.

What to annex For sufficiently small files, the overhead of a symlink and couple of directory entries is greater than the cost of a compressed second copy. When this happens depends on several variables, and will probably depend on the file content in a particular collection of email. I did a few trials of different settings for annex.largefiles to come to a threshold of largerthan=32k 1. For the curious, my experimental results are below. One potentially surprising aspect is that annexing even a small fraction of the (largest) files yields a big drop in storage overhead.
Threshold fraction annexed overhead
0 100% 30%
8k 29% 13%
16k 12% 9.4%
32k 7% 8.9%
48k 6% 8.9%
100k 3% 9.1%
256k 2% 11%
(git) 0 % 57%
In the end I chose to err on the side of annexing more files (for the flexibility of deletion) rather than potentially faster operations with fewer annexed files at the same level of overhead. Summarizing the configuration settings for git-annex (some of these are actually defaults, but not in my environment).
$ git config annex.largefiles largerthan=32k
$ git config annex.dotfiles true
$ git config annex.synccontent true

Delivering mail To get new mail, I do something like
# compute a date based folder under $HOME/Maildir
$ dest = $(folder)
# deliver mail to $ dest  (somehow).
$ notmuch new
$ git -C $HOME/Maildir add $ folder 
$ git -C $HOME/Maildir diff-index --quiet HEAD $ folder    git -C $HOME/Maildir commit -m 'mail delivery'
The call to diff-index is just an optimization for the case when nothing was delivered. The default configuration of git-annex will automagically annex any files larger than my threshold. At this point the git-annex repo knows nothing about tags. There is some git configuration that can speed up the "git add" above, namely
$ git config core.untrackedCache true
$ git config core.fsmonitor true
See git-status(1) under "UNTRACKED FILES AND PERFORMANCE" Defining notmuch as a git remote Assuming git-remote-notmuch is somewhere in your path, you can define a remote to connect to the default notmuch database.
$ git remote add database notmuch::
$ git fetch database
$ git merge --allow-unrelated database
The --allow-unrelated should be needed only the first time. In my case the many small files used to represent the tags (one per message), use a noticeable amount of disk space (in my case about the same amount of space as the xapian database). Once you start merging from the database to the git repo, you will likely have some conflicts, and most conflict resolution tools leave junk lying around. I added the following .gitignore file to the top level of the repo
*.orig
*~
This prevents our cavalier use of git add from adding these files to our git history (and prevents pushing random junk to the notmuch database. To push the tags from git to notmuch, you can run
$ git push database master
You might need to run notmuch new first, so that the database knows about all of the messages (currently git-remote-notmuch can't index files, only update metadata). git annex sync should work with the new remote, but pushing back will be very slow 2. I disable automatic pushing as follows
$ git config remote.database.annex-push false
Unsticking the database remote If you are debugging git-remote-notmuch, or just unlucky, you may end up in a sitation where git thinks the database is ahead of your git remote. You can delete the database remote (and associated stuff) and re-create it. Although I cannot promise this will never cause problems (because, computers), it will not modify your local copy of the tags in the git repo, nor modify your notmuch database.
$ git remote rm database
$ git update-rf -d notmuch/master
$ rm -r .git/notmuch
Fine tuning notmuch config
  • In order to avoid dealing with file renames, I have
      notmuch config maildir.synchronize_flags false
    
  • I have added the following to new.ignore:
       .git;_notmuch_metadata;.gitignore
    

  1. I also had to set annex.dotfiles to true, as many of my maildirs follow the qmail style convention of starting with a .
  2. I'm not totally clear on why it so slow, but certainly git-annex tries to push several more branches, and these are ignored by git-remote-annex.

5 August 2025

Matthew Garrett: Cordoomceps - replacing an Amiga's brain with Doom

There's a lovely device called a pistorm, an adapter board that glues a Raspberry Pi GPIO bus to a Motorola 68000 bus. The intended use case is that you plug it into a 68000 device and then run an emulator that reads instructions from hardware (ROM or RAM) and emulates them. You're still limited by the ~7MHz bus that the hardware is running at, but you can run the instructions as fast as you want.

These days you're supposed to run a custom built OS on the Pi that just does 68000 emulation, but initially it ran Linux on the Pi and a userland 68000 emulator process. And, well, that got me thinking. The emulator takes 68000 instructions, emulates them, and then talks to the hardware to implement the effects of those instructions. What if we, well, just don't? What if we just run all of our code in Linux on an ARM core and then talk to the Amiga hardware?

We're going to ignore x86 here, because it's weird - but most hardware that wants software to be able to communicate with it maps itself into the same address space that RAM is in. You can write to a byte of RAM, or you can write to a piece of hardware that's effectively pretending to be RAM[1]. The Amiga wasn't unusual in this respect in the 80s, and to talk to the graphics hardware you speak to a special address range that gets sent to that hardware instead of to RAM. The CPU knows nothing about this. It just indicates it wants to write to an address, and then sends the data.

So, if we are the CPU, we can just indicate that we want to write to an address, and provide the data. And those addresses can correspond to the hardware. So, we can write to the RAM that belongs to the Amiga, and we can write to the hardware that isn't RAM but pretends to be. And that means we can run whatever we want on the Pi and then access Amiga hardware.

And, obviously, the thing we want to run is Doom, because that's what everyone runs in fucked up hardware situations.

Doom was Amiga kryptonite. Its entire graphical model was based on memory directly representing the contents of your display, and being able to modify that by just moving pixels around. This worked because at the time VGA displays supported having a memory layout where each pixel on your screen was represented by a byte in memory containing an 8 bit value that corresponded to a lookup table containing the RGB value for that pixel.

The Amiga was, well, not good at this. Back in the 80s, when the Amiga hardware was developed, memory was expensive. Dedicating that much RAM to the video hardware was unthinkable - the Amiga 1000 initially shipped with only 256K of RAM, and you could fill all of that with a sufficiently colourful picture. So instead of having the idea of each pixel being associated with a specific area of memory, the Amiga used bitmaps. A bitmap is an area of memory that represents the screen, but only represents one bit of the colour depth. If you have a black and white display, you only need one bitmap. If you want to display four colours, you need two. More colours, more bitmaps. And each bitmap is stored in an independent area of RAM. You never use more memory than you need to display the number of colours you want to.

But that means that each bitplane contains packed information - every byte of data in a bitplane contains the bit value for 8 different pixels, because each bitplane contains one bit of information per pixel. To update one pixel on screen, you need to read from every bitmap, update one bit, and write it back, and that's a lot of additional memory accesses. Doom, but on the Amiga, was slow not just because the CPU was slow, but because there was a lot of manipulation of data to turn it into the format the Amiga wanted and then push that over a fairly slow memory bus to have it displayed.

The CDTV was an aesthetically pleasing piece of hardware that absolutely sucked. It was an Amiga 500 in a hi-fi box with a caddy-loading CD drive, and it ran software that was just awful. There's no path to remediation here. No compelling apps were ever released. It's a terrible device. I love it. I bought one in 1996 because a local computer store had one and I pointed out that the company selling it had gone bankrupt some years earlier and literally nobody in my farming town was ever going to have any interest in buying a CD player that made a whirring noise when you turned it on because it had a fan and eventually they just sold it to me for not much money, and ever since then I wanted to have a CD player that ran Linux and well spoiler 30 years later I'm nearly there. That CDTV is going to be our test subject. We're going to try to get Doom running on it without executing any 68000 instructions.

We're facing two main problems here. The first is that all Amigas have a firmware ROM called Kickstart that runs at powerup. No matter how little you care about using any OS functionality, you can't start running your code until Kickstart has run. This means even documentation describing bare metal Amiga programming assumes that the hardware is already in the state that Kickstart left it in. This will become important later. The second is that we're going to need to actually write the code to use the Amiga hardware.

First, let's talk about Amiga graphics. We've already covered bitmaps, but for anyone used to modern hardware that's not the weirdest thing about what we're dealing with here. The CDTV's chipset supports a maximum of 64 colours in a mode called "Extra Half-Brite", or EHB, where you have 32 colours arbitrarily chosen from a palette and then 32 more colours that are identical but with half the intensity. For 64 colours we need 6 bitplanes, each of which can be located arbitrarily in the region of RAM accessible to the chipset ("chip RAM", distinguished from "fast ram" that's only accessible to the CPU). We tell the chipset where our bitplanes are and it displays them. Or, well, it does for a frame - after that the registers that pointed at our bitplanes no longer do, because when the hardware was DMAing through the bitplanes to display them it was incrementing those registers to point at the next address to DMA from. Which means that every frame we need to set those registers back.

Making sure you have code that's called every frame just to make your graphics work sounds intensely irritating, so Commodore gave us a way to avoid doing that. The chipset includes a coprocessor called "copper". Copper doesn't have a large set of features - in fact, it only has three. The first is that it can program chipset registers. The second is that it can wait for a specific point in screen scanout. The third (which we don't care about here) is that it can optionally skip an instruction if a certain point in screen scanout has already been reached. We can write a program (a "copper list") for the copper that tells it to program the chipset registers with the locations of our bitplanes and then wait until the end of the frame, at which point it will repeat the process. Now our bitplane pointers are always valid at the start of a frame.

Ok! We know how to display stuff. Now we just need to deal with not having 256 colours, and the whole "Doom expects pixels" thing. For the first of these, I stole code from ADoom, the only Amiga doom port I could easily find source for. This looks at the 256 colour palette loaded by Doom and calculates the closest approximation it can within the constraints of EHB. ADoom also includes a bunch of CPU-specific assembly optimisation for converting the "chunky" Doom graphic buffer into the "planar" Amiga bitplanes, none of which I used because (a) it's all for 68000 series CPUs and we're running on ARM, and (b) I have a quad core CPU running at 1.4GHz and I'm going to be pushing all the graphics over a 7.14MHz bus, the graphics mode conversion is not going to be the bottleneck here. Instead I just wrote a series of nested for loops that iterate through each pixel and update each bitplane and called it a day. The set of bitplanes I'm operating on here is allocated on the Linux side so I can read and write to them without being restricted by the speed of the Amiga bus (remember, each byte in each bitplane is going to be updated 8 times per frame, because it holds bits associated with 8 pixels), and then copied over to the Amiga's RAM once the frame is complete.

And, kind of astonishingly, this works! Once I'd figured out where I was going wrong with RGB ordering and which order the bitplanes go in, I had a recognisable copy of Doom running. Unfortunately there were weird graphical glitches - sometimes blocks would be entirely the wrong colour. It took me a while to figure out what was going on and then I felt stupid. Recording the screen and watching in slow motion revealed that the glitches often showed parts of two frames displaying at once. The Amiga hardware is taking responsibility for scanning out the frames, and the code on the Linux side isn't synchronised with it at all. That means I could update the bitplanes while the Amiga was scanning them out, resulting in a mashup of planes from two different Doom frames being used as one Amiga frame. One approach to avoid this would be to tie the Doom event loop to the Amiga, blocking my writes until the end of scanout. The other is to use double-buffering - have two sets of bitplanes, one being displayed and the other being written to. This consumes more RAM but since I'm not using the Amiga RAM for anything else that's not a problem. With this approach I have two copper lists, one for each set of bitplanes, and switch between them on each frame. This improved things a lot but not entirely, and there's still glitches when the palette is being updated (because there's only one set of colour registers), something Doom does rather a lot, so I'm going to need to implement proper synchronisation.

Except. This was only working if I ran a 68K emulator first in order to run Kickstart. If I tried accessing the hardware without doing that, things were in a weird state. I could update the colour registers, but accessing RAM didn't work - I could read stuff out, but anything I wrote vanished. Some more digging cleared that up. When you turn on a CPU it needs to start executing code from somewhere. On modern x86 systems it starts from a hardcoded address of 0xFFFFFFF0, which was traditionally a long way any RAM. The 68000 family instead reads its start address from address 0x00000004, which overlaps with where the Amiga chip RAM is. We can't write anything to RAM until we're executing code, and we can't execute code until we tell the CPU where the code is, which seems like a problem. This is solved on the Amiga by powering up in a state where the Kickstart ROM is "overlayed" onto address 0. The CPU reads the start address from the ROM, which causes it to jump into the ROM and start executing code there. Early on, the code tells the hardware to stop overlaying the ROM onto the low addresses, and now the RAM is available. This is poorly documented because it's not something you need to care if you execute Kickstart which every actual Amiga does and I'm only in this position because I've made poor life choices, but ok that explained things. To turn off the overlay you write to a register in one of the Complex Interface Adaptor (CIA) chips, and things start working like you'd expect.

Except, they don't. Writing to that register did nothing for me. I assumed that there was some other register I needed to write to first, and went to the extent of tracing every register access that occurred when running the emulator and replaying those in my code. Nope, still broken. What I finally discovered is that you need to pulse the reset line on the board before some of the hardware starts working - powering it up doesn't put you in a well defined state, but resetting it does.

So, I now have a slightly graphically glitchy copy of Doom running without any sound, displaying on an Amiga whose brain has been replaced with a parasitic Linux. Further updates will likely make things even worse. Code is, of course, available.

[1] This is why we had trouble with late era 32 bit systems and 4GB of RAM - a bunch of your hardware wanted to be in the same address space and so you couldn't put RAM there so you ended up with less than 4GB of RAM

comment count unavailable comments

Michael Ablassmeier: PVE 9.0 - Snapshots for LVM

The new Proxmox release advertises a new feature for easier snapshot handling of virtual machines whose disks are stored on LVM volumes, I wondered.. whats the deal..? To be able to use the new feature, you need to enable a special flag for the LVM volume group. This example shows the general workflow for a fresh setup. 1) Create the volume group with the snapshot-as-volume-chain feature turned on:
 pvesm add lvm lvmthick --content images --vgname lvm --snapshot-as-volume-chain 1
2) From this point on, you can create virtual machines right away, BUT those virtual machines disks must use the QCOW image format for their disk volumes. If you use the RAW format, you wont be able to create snapshots, still.
 VMID=401
 qm create $VMID --name vm-lvmthick
 qm set $VMID -scsi1 lvmthick:2,format=qcow2
So, why would it make sense to format the LVM volume as QCOW? Snapshots on LVM thick provisioned devices are, as everybody knows, a very I/O intensive task. Besides each snapshot, a special -cow Device is created that tracks the changed block regions and the original block data for each change to the active volume. This will waste quite some space within your volume group for each snapshot. Formatting the LVM volume as QCOW image, makes it possible to use the QCOW backing-image option for these devices, this is the way PVE 9 handles these kind of snapshots. Creating a snapshot looks like this:
 qm snapshot $VMID id
 snapshotting 'drive-scsi1' (lvmthick3:vm-401-disk-0.qcow2)
 Renamed "vm-401-disk-0.qcow2" to "snap_vm-401-disk-0_id.qcow2" in volume group "lvm"
 Rounding up size to full physical extent 1.00 GiB
 Logical volume "vm-401-disk-0.qcow2" created.
 Formatting '/dev/lvm/vm-401-disk-0.qcow2', fmt=qcow2 cluster_size=131072 extended_l2=on preallocation=metadata compression_type=zlib size=1073741824 backing_file=snap_vm-401-disk-0_id.qcow2 backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
So it will rename the current active disk and create another QCOW formatted LVM volume, but pointing it to the snapshot image using the backing_file option. Neat.

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