Should universities switch away from hosting their own email and join the Google bandwagon?
Adi Kamdar wrote to
the Students for Free Culture discussion mailing list
linking us to a
Yale Daily News
article discussing an "almost-definite" switch for Yale to Google Apps for Education.
Adi asked for thoughts, so here are mine.
Yesterday I stumbled upon an interesting and broken behaviour of Django: Running two instances with the same memcached as cache backend might result in displaying the wrong template from the cache in case we have template files with the same name but a different content.
This behaviour is also visible in all django applications which use the cache backend without taking care of settings.CACHE_MIDDLEWARE_KEY_PREFIX. As mentioned in the bug report a design decision is necessary here, as the setting was only supposed to be used in middlewares. On the other side not honouring the setting everywhere makes it impossible to use different (unrelated) Django instances with one memcached. While this is not such a big issue for template data, it should be - for example - possible to insert faked django CMS user permissions into memcached as they are cached there, too.
One possible solution is to ensure that settings.CACHE_MIDDLEWARE_KEY_PREFIX (or a similar setting with a better name) is used for every access. Using the following snippet as custom cache backend ensures this. Additionally it is much harder to insert faked cache content by using a md5 hexdigest as key. Although you should never store sensitive data in memcached - if you need to cache such data, use locmem, file or db as cache backend, as they allow to limit access to the data properly.
from django.conf import settings
from django.core.cache.backends.memcached import CacheClass as DjangoMemcachedCacheClass
from django.utils.hashcompat import md5_constructor
class CacheClass(DjangoMemcachedCacheClass):
def __init__(self, server, params):
self.key_prefix = settings.CACHE_MIDDLEWARE_KEY_PREFIX
super(CacheClass, self).__init__(server, params)
def _genkey(self, origkey):
return md5_constructor("%s:%s" %(self.key_prefix, origkey)).hexdigest()
def add(self, key, value, timeout=0):
return super(CacheClass, self).add(self._genkey(key), value, timeout)
def get(self, key, default=None):
return super(CacheClass, self).get(self._genkey(key), default)
def set(self, key, value, timeout=0):
return super(CacheClass, self).set(self._genkey(key), value, timeout)
def delete(self, key):
return super(CacheClass, self).delete(self._genkey(key))
def get_many(self, keys):
return super(CacheClass, self).get_many(self._genkey(key))
def incr(self, key, delta=1):
return super(CacheClass, self).incr(self._genkey(key), delta)
def decr(self, key, delta=1):
return super(CacheClass, self).decr(self._genkey(key), delta)
Apparently, there s some hype in the Ubuntu community about Ruby 1.9.2, so let s clarify: it would be totally irresponsible to try to ship Ruby 1.9.2 in Debian Squeeze or Ubuntu Lucid.
Ruby 1.9.2 has not been released yet:
Want a sound card? Want a cleared sound that is not contaminated by electromagnetic interference in you computer s case? Want that all to work in Linux?
I did. So I got me one of theseUSB sound cards. It arrived today in a tiny padded envelope.
And it works with Linux. Just plug and play. PulseAudio makes it all trivial. The device ID as reported by lsusb is 0c76:1607 JMTek, LLC. The text on the back of the device says Model HY544 USB 3D Sound Pnp FC CE Made in China .
I found out yesterday that my
university s Microsoft
Exchange Server account stopped forwarding my mail on 8
December 2009. As a result, mail accumulated there and remained
unseen.
Dear examiners, paper authors, supervisors, sponsors,
participants, and peers who responded to my calls and cries related
to my PhD thesis. I am
terribly sorry that you were subjected to this. You replied usually
within a few days, but I still sent you reminder after reminder in
the weeks to follow. You must have thought that I was a real dork.
Please forgive me. I really appreciate your patience!
I filed a ticket with my university s IT service provider, which got closed the
next day with it should now work again . That wasn t going to cut
it for me, so I reopened the ticket, asking for an explanation.
Next, I received an apology with a bit of speculation.
After a bit of research, it seems that the reason was to be
found in the inconsistency of being an external staff member
(i.e. an e-mail address outside of the Active
Directory domain), but still having an account on the
server.
On 8 December 2009, the server was upgraded with a service pack.
This caused Exchange to go a little manic on the housekeeping.
After all, why would anyone ever want to forward their e-mail
elsewhere, and still have an account?
Well, I certainly don t want an account, and yet I have to have
one: Microsoft has bought their ways into the university and spread
their germs all across, I need credentials to be able to access
shared files, print, browse the library, or search the phone
book.
However, considering that UL s Outlook Web
Access instance does not let users of decent browsers search
their mailboxes (a premium feature
reserved for users of Internet Exploder), one cannot manipulate
more than a page-full of e-mails at a time, bounce messages, or do
many of the other operations that make dealing with large amounts
of e-mail possible, and because Exchange mail if it doesn t get
lost in the first place sucks in so many other ways, I certainly
prefer my mail to be handled by a real
mail server with a proper
mail filter (writeup in progress).
Maybe the Exchange service pack was simply designed to get rid
of outcasts like me who don t buy into the low-Microsoft-quality
vendor
lock-in? We ll never know, thanks to the proprietarity
of their software (and the fact that the university service
provider apparently does not keep logs of changes).
NP:
AC/DC: Back in Black
I ve just put the slides of my talk on Debian and Ubuntu online.
Don t hesitate to post comments to ask for clarifications where needed (it might be difficult to understand some parts of the slides without being in the room).
Clarifications:
This has robbed me of several days of my life, so I want to bring Google juice this this problem.
IF you have a Pylons or TurboGears application or anything else that uses the fantastic EvalException WSGI middleware for web debugging of you web program and have the following symptom:
* on a crash the traceback page shows up, but it has no css style and no images I do
not like it when people tell Web 2.0 sites to send me invitation
e-mail. I won t enumerate the reasons here. But there is one
reason for why I don t like you passing on my address to those
sites, which is subject of this article:
Unlike popular belief, the Web 2.0 is not a money-printing
machine. It s a long road until you can actually generate real
money with user content. Therefore, some shadey sites are probably
selling contact details to advertisers to make ends meet while
hoping for the big cashflow.
I don t have any data to back this up, and I want to change
that:
Please tell all your Web 2.0 sites to send me an invitation! Please use an address in theThank you for your time. Keep in mind: the more, the merrier. I ll make sure to report back on the outcome of this little experiment right here, so watch this space. NP: Billy Joel: Cold Spring Harborsignmeup.madduck.netdomain for that, and make sure to include the domain name of the service to which you sign me up before the@symbol. Also append a hyphen/dash and a random, short string. More on that in just a sec. For instance, if you are one of those people that believes that letting people know where you are (and have been) at any point in time, tell Foursquare to send an invitation to:The reason for the random, short string ( ponies ) is simply so that I can later cross-check that a message receiving spam actually went through a social networking site I intend to catalog the invitation messages.foursquare.com-ponies@signmeup.madduck.net
upstream maintainers, that is the people who write/maintain the software that we package for Debian. It is meant to explain why, in some cases, Debian Developers prefer to
mutilateyour work rather than upload it to Debian Archives in a state that gives it proper credit. And to apologize. These opinions are my own, but I have a faint feeling that I'm not the only Debian Developer working like that, and that this few words could help soothe the relation betwenn Debian Developers and Upstream Maintainers, which can be quite tense some times... It happens unfortunately quite often (too often!) that I disable (or don't enable) features in programs I package. Exact reasons vary, but they essentially fall into two categories:
upstreamdeveloper I've offended by stripping down apparently carelessly their beautiful software before uploading to the Debian Archives; I hope they now understand why I've done that. Note to users: it is not because one of the features of your favorite software has been disabled by its (Debian) maintainer that you need to turn away from Debian ! Rather, file a bug report against the package. You'll get the reasons why the feature was disabled, and you have a chance to convince the maintainer to switch it back on.
If you read the literature on tricksters, you will confront a string of words that capture the moral quality and sensibilities of these figures, figures scattered across time and place and largely enshrined in myths and stories:
Cunning, deceit, lying, provocateur, mischief, audacious, thief, play, shrewdness, audacity, grotesque, over the top, appetite, shocking, fun, delight, wit, trap, subversive, ability, wanderer.These figures, which include Coyote, Loki, Hermes, and Eshu, among many more, push the envelope of what is morally acceptable and in so doing, argues Lewis Hyde (in his tome on the subject), renew and revitalize culture, especially the moral stuff of culture. They are not only boundary crossers, they are boundary makers. As the title of his book so succinctly and masterfully broadcasts Trickster Makes this World. Or as he suggests with a bit more elaboration:
I want to argue a paradox that the myth asserts: that the origins, liveliness, and durability of cultures require that there be a space for figures whose function is to uncover and disrupt the very things that cultures are based on p. 9At the opening of the book, Hyde asks whether there are tricksters in modern industrial societies. His answer is a plain no. The con man who might share some similarities does not qualify. For in fact what is needed is either a polytheistic system or lacking that, he needs at least a relationship to other powers, to people, to instructions, and traditions that can manage the odd double attitude of both insisting that boundaries be respected and recognizing that in the long run their liveliness depends on having those boundaries regularly distributed p.13 He does locate the spirit of the trickster in spirited individuals: in Picasso, in Frederick Douglass, in laudable figures who push certain boundaries and renew our world for the better but nonetheless fall short of the archetypal trickster. I bet it is pretty obvious where I am going with all of this given my object of study: phreakers, hackers, and trollers. The trickster does exist across America, across Europe, really across the world and it is not in myth but in embodied in group and living practice: in that of the prankster, hacker, the phreaker, the troller (all of whom, have their own unique elements of course, but so does each trickster). Their relationship to other powers are many and can be located in terms of information, intellectual property, the government, language itself, institutions of power like the FBI and AT&T. The list is not short. For a few years now I have been thinking about the linkages between the trickster and hackers as well as the troller but it was only in the fall when I found myself trapped in a hospital for a week that I finally cracked open the book by Hyde and devoured it. Within a the first few pages, it was undeniable: there are many links to be made between the trickster and hacking. Many of these figures, push boundaries of all sorts: they upset ideas of propriety and property; they use their sharpened wits sometimes for play, sometimes for political ends; they get trapped by their cunning (which happens ALL the time with tricksters! That is how they learn); and they remake the world, technically, socially, and legally and includes software, licensing and even forms of literature (think textfile, the Jargon File or most dramatically, ED). But if the trickster generally resides in myth, and the trickster of the information age resides in practice, myth matters everywhere because there is a mythos created around these figures. Sometimes the mythos is propagated these groups (take a look of ED for example or Phrack in the past) and of course the media has played an undeniable role. And yet, unlike what is represented in the pages of Hyde, there are living, actual bodies in motion, in conversation, in transformation, a group that goes far beyond the other more controlled and bounded tricksters we might be able to locate in society, such as artistic/political groups like the Yes Men. But the most shocking (or hard to think through) element lies less in the many associations one can make, but in the following curious fact. For the most part the trickster is enshrined in myth and stories but the tricksters I am referring to are in fact full-bodied, full-blooded groups of people who are actually engaging in all sorts of acts of trickery. This is culture not in the sense of art and myth but people and practice and this of course makes an (ethical) difference. What happens when you are the recipient not of a story offered an elder, but the recipient of trickery, an act of pranking or trolling, for example? What happens when you can trace all sorts of instances of boundary re-shifting and remaking, as with the GPL? I think this, even more than the linkages, is what makes this connection so remarkable and I trying to think through what it means to have a figure that we can find and talk to, as opposed to one embodied in myth and story. For now I am going to leave this post short and in the next installment, will start raising some of the connections between trickery and variants of hacking and trolling.
If you read the literature on tricksters, you will confront a string of words that capture the moral quality and sensibilities of these figures, figures scattered across time and place and largely enshrined in myths and stories:
Cunning, deceit, lying, provocateur, mischief, audacious, thief, play, shrewdness, audacity, grotesque, over the top, appetite, shocking, fun, delight, wit, trap, subversive, ability, wanderer.These figures, which include Coyote, Loki, Hermes, and Eshu, among many more, push the envelope of what is morally acceptable and in so doing, argues Lewis Hyde (in his tome on the subject), renew and revitalize culture, especially the moral stuff of culture. They are not only boundary crossers, they are boundary makers. As the title of his book so succinctly and masterfully broadcasts Trickster Makes this World. Or as he suggests with a bit more elaboration:
I want to argue a paradox that the myth asserts: that the origins, liveliness, and durability of cultures require that there be a space for figures whose function is to uncover and disrupt the very things that cultures are based on p. 9At the opening of the book, Hyde asks whether there are tricksters in modern industrial societies. His answer is a plain no. The con man who might share some similarities does not qualify. For in fact what is needed is either a polytheistic system or lacking that, he needs at least a relationship to other powers, to people, to instructions, and traditions that can manage the odd double attitude of both insisting that boundaries be respected and recognizing that in the long run their liveliness depends on having those boundaries regularly distributed p.13 He does locate the spirit of the trickster in spirited individuals: in Picasso, in Frederick Douglass, in laudable figures who push certain boundaries and renew our world for the better but nonetheless fall short of the archetypal trickster. I bet it is pretty obvious where I am going with all of this given my object of study: phreakers, hackers, and trollers. The trickster does exist across America, across Europe, really across the world and it is not in myth but in embodied in group and living practice: in that of the prankster, hacker, the phreaker, the troller (all of whom, have their own unique elements of course, but so does each trickster). Their relationship to other powers are many and can be located in terms of information, intellectual property, the government, language itself, institutions of power like the FBI and AT&T. The list is not short. For a few years now I have been thinking about the linkages between the trickster and hackers as well as the troller but it was only in the fall when I found myself trapped in a hospital for a week that I finally cracked open the book by Hyde and devoured it. Within a the first few pages, it was undeniable: there are many links to be made between the trickster and hacking. Many of these figures, push boundaries of all sorts: they upset ideas of propriety and property; they use their sharpened wits sometimes for play, sometimes for political ends; they get trapped by their cunning (which happens ALL the time with tricksters! That is how they learn); and they remake the world, technically, socially, and legally and includes software, licensing and even forms of literature (think textfile, the Jargon File or most dramatically, ED). But if the trickster generally resides in myth, and the trickster of the information age resides in practice, myth matters everywhere because there is a mythos created around these figures. Sometimes the mythos is propagated these groups (take a look of ED for example or Phrack in the past) and of course the media has played an undeniable role. And yet, unlike what is represented in the pages of Hyde, there are living, actual bodies in motion, in conversation, in transformation, a group that goes far beyond the other more controlled and bounded tricksters we might be able to locate in society, such as artistic/political groups like the Yes Men. But the most shocking (or hard to think through) element lies less in the many associations one can make, but in the following curious fact. For the most part the trickster is enshrined in myth and stories but the tricksters I am referring to are in fact full-bodied, full-blooded groups of people who are actually engaging in all sorts of acts of trickery. This is culture not in the sense of art and myth but people and practice and this of course makes an (ethical) difference. What happens when you are the recipient not of a story offered an elder, but the recipient of trickery, an act of pranking or trolling, for example? What happens when you can trace all sorts of instances of boundary re-shifting and remaking, as with the GPL? I think this, even more than the linkages, is what makes this connection so remarkable and I trying to think through what it means to have a figure that we can find and talk to, as opposed to one embodied in myth and story. For now I am going to leave this post short and in the next installment, will start raising some of the connections between trickery and variants of hacking and trolling.
Stay tuned, and if interested, join discussions@planetforge.org to discuss this topic.
P.S.: yes, it s a rebirth of CoopX, somehow (see the coopx tag in my blog for more details)
So far the networking of virtual machines has usually been managed by configuring a Virtual Ethernet Bridge (VEB) in the host, i.e. the good old implementation of 802.1D in the Linux Kernel:
A Virtual Ethernet Bridge (VEB) is a capability within a physical end station that supports local bridging between multiple virtual end stations and (optionally) the external bridging environment.While this works well and in some cases is the best solution, in other setups performances or policy needs dictate that the traffic between virtual machines is forwarded to an external bridge (the Ethernet switch connected to the host) and back without having in the host a real bridge learning MAC addresses from its ports and implementing the STP. Enters the VEPA:
A Virtual Ethernet Port Aggregator (VEPA) is a capability within a physical end station that collaborates with an adjacent, external bridge to provide bridging support between multiple virtual end stations and external networks. The VEPA collaborates by forwarding all station-originated frames to the adjacent bridge for frame processing and frame relay (including "hairpin" forwarding) and by steering and replicating frames received from the VEPA uplink to the appropriate destinations.Support for VEPAs has been added to Linux 2.6.33 with a simple change to the macvlan driver. The next step will be to use the macvtap driver (available in 2.6.34), which exposes a tap character device usable by kvm-qemu and "connected" to a macvlan-like interface.
In November 2007, we bought two of the first Eee PC netbooks available in North America: the model 4G in pearl white, one for me, and one for my wife. My plan was to start the Debian Eee PC project and get Debian working on them both which, thanks to the work of everyone on the team, has been a great success. Fast forward to February 2010, and they are still serving us well. Here is a list of hardware enhancements and issues over the past two years of continuous use:
Battery life
Asus claims 3.5hrs for the model 4G, though I don t think we ever experienced anything better than 2.5 hrs with wifi in operation. Today, I m down to something short of 2 hrs. If you consider the Lithium ion battery article on Wikipedia to be accurate, it is typical to permanently lose 20% capacity per year, so this sounds about right for the age of the battery.
Touchpad
The touchpad itself is fine. The buttons are not. They are hard to push and prone to become less responsive after a while, or to fail entirely. I now really have to bear down hard on my left button to make it work. Because the buttons are soldered to the motherboard, they would be hard to replace. Configuring the synaptics driver for tap-to-click is an acceptable workaround. Also, one of the first purchases we made was the Logitech VX Nano, one for each Eee, so most of the time now, we use our mice, falling back to the touchpad only when using a mouse is inconvenient due to space constraints (e.g. on the bus).
Keyboard
After two years of continuous use, both of our keyboards needed replacing. Some of the keys had been pounded flat and needed surgery (rubber springs sliced out of a scavenged Acer netbook keyboard and grafted on) to make them usable again. And aesthetically, the keyboards have really suffered, with a good percentage of the markings on the keycaps partially or completely eroded off.
Fortunately, for $3 plus $10 shipping each, new keyboards can be ordered from a Chinese e-Bay seller. But with the new keyboards, there is still the problem with excessive flex in the keyboard making some keys less responsive than others. I m considering trying this hack to solve the problem.
Display
I have no complaints about the matte finish displays of either Eee. Both have stood up well. People tell me they don t care for a 7 display, but I find it bright, crisp and easy to get along with, so long as you maximize windows and increase font size as needed (e.g. for reading PDF books and magazines). When I really need the extra real estate, I just hook up an external monitor.
Fan
Some people complain about the noise of the fan, from the otherwise silent 4G (due to the lack of a hard drive) and seek ways to limit the amount of time the fan runs. We ve never had that problem. However, if any plastic bits break off inside the Eee, they will eventually find their way to your fan and get wedged. This has happened twice: once in my wife s Eee, and once in mine. Disassembly of the Eee to clear the blockage and get the fan running again was relatively painless both times.
Plastic bits
About those plastic bits: In my wife s case, I think the bit was some extruded plastic from the molding that had broken off. In my case, it was a deteriorating plastic post which was holding the hinge in place. More about this later.
Sound
Unfortunately, the integrated sound seems to be particularly sensitive to heat. During both fan failures, sound cut out. On my wife s system, it never fully recovered, and now only works on alternate Tuesdays, whereas on mine, after I unwedged the fan and brought the heat down, sound has functioned properly ever since. (Update: see my comments below on power adapters for an alternate theory about what killed sound.) We are waiting now for the delivery of a cheap ($1.42 including shipping, again from China) 3D Sound USB device which is reported to work on Linux. While some users complain about hum with this device, we re cautiously optimistic that on the Eee it won t be an issue. If it is, oh well, a buck and a half is a small gamble.
Display hinge
The plastic posts that hold the anchors for the machine screws for the hinge are fragile. Three out of four of these posts in my Eee have shattered, leaving the left hinge to float freely. For the past two days I was distressed about how I could fix this. Based on some helpful suggestions from #eeepc @ irc.freenode.net, I had worked out a plan to rebuild one of the posts with two-part epoxy, sand it and the fractured stub of the post, and use cyanoacrylate glue to affix it to the case. It sounded like fiddly work for which I didn t hold much hope of success. But this morning, I realized that the plastic in the bottom of the case was still sound, and that I could drop a screw into that hole, and with pliers, line up the anchor on the other side. This appears to work! I ll handle that hinge with care, but it should do me until I eventually repurpose the machine to some daily use that is less stressful on the hinge than daily travel on the bus.
SSD and SDHC
Some people were initially worried that the limited write life an SSD meant that you needed to take special measures to avoid its premature death, which I have always regarded as a myth. Our 4G SSDs each have no swap space, and ext3 filesystems. At the two year point, there are no problems. I expect our SSDs to outlast the other components.
We did, however, eventually find the 4G to be a bit on the small side. We now each have Kingston 4G micro-SDHC cards for a bit of extra capacity for large media files and for some extra space for the apt cache. I recently priced the Lexan version of this card at $19 for a two-pack at Wal-mart, and these seem to work in the model 4G just as well (which seems to be an issue with this model not all SDHC cards work).
Memory
We found the 512M that came with the 4G somewhat constraining. Without any swap space (so we could maximize the space available on the small SSD) we decided our systems really needed a memory upgrade. At the time, 2G didn t seem overly expensive (though I no longer remember the exact price) so we splurged on 2G for each system, even though that was probably more than we needed.
Power adapter
When I first wrote this article, I forgot to mention the power adapter. The model 4G uses an unusual 9.5V power adapter for which it is hard to find a generic replacement. This unit is prone to fail in two places: in rare cases, (one out of 6 units that I have in some way assisted with: 3 of them mine, 3 belonging to others,) it will break at the wall plug end. The plug swivels into the unit for easy storage, but this adds a point of failure. More commonly, (in 3 out of six of the units,) the wires at the netbook plug end will fray due to stress on the non-angled cord, leading either to no connect, or to a short. In fact, since in the case of my wife s adapter, the netbook end of the cable shorted, making the cable heat up and the system spontaneously shut down after a little while, we can t say for sure whether the overheating of the Eee took out integrated sound, or whether this short did. On the one hand, I know for certain my own system, which never suffered a short, has responded to overheating by making the sound flaky, but it has never taken out sound completely. On the other hand, shorting the power cable can t be very good for the Eee, so who knows, maybe that s what ultimately killed my wife s Eee s sound.
This is where it helps to have soldering skills, or a friend who can do the repair for you. In my case, it was the latter. While I was waiting for a replacement adapter I had ordered, we also found on eeeuser.com part#s for replacement plugs and sleeves from Digikey, total cost $20 including shipping, 10 pieces each. Cutting off the bad plugs on three units and attaching the new was a quick, straightforward operation, and succeeded in two out of three cases. Having carefully checked the failed repair, we deduced that the failure in that unit was at the wall end, and we judged there was nothing further we could do to try to save it. Even the unit that had previously shorted was returned to perfect health and has been in operation trouble-free ever since.
Conclusion
After over two years of continuous use, the model 4G has held up well for a $400 system. We definitely feel we have received our money s worth of value over that time. All of the problems we ve experienced so far have been fixable at very little expense, and we expect them to last at least another year before we seriously consider replacing them. In the next several months, I plan to order a high capacity 8-cell 10400mAh battery for my own system so that I can enjoy a 5-6 hr run time. The purchase will be roughly $55 including shipping, the most expensive purchase for my system to date, but still well worth it to extend the 4G s lifespan for another year or more.
I propose a new feature for email software: Cosmetic carbon copy. CCC works very
similarly to today's carbon copy feature: If you put an
address in the CCC: list, when the recipients open the message, they can see
the address. The one difference is that with "cosmetic" carbon copy, the CCC:d
address never recieves the message.
An example might illustrate the situation. Let's say someone (Alice) wants to
invite Bob to a movie but doesn't want Charlie to come. She might send this email:
From: alice@example.com To: bob@example.com CCC: charlie@example.com Subject: MOOOVIEEE!
Hey all my friends, join me for a movie tonight!When Alice sends the email, Bob recives a copy. Bob thinks that Charlie received a copy, as he will be in the CC list. But Alice's mail software never sent Charlie a copy. So Alice can relax, knowing that Bob won't forward a copy to Charlie, since Bob thinks he already received it. Alice and Bob will meet up without Charlie, and Alice will quietly sigh in relief.
It's been awhile since I last posted, but I felt the need to do so after my recent flight through ATL. While I was waiting for my connection the loudspeakers announced that we were at threat level "Orange" and that we, the people, had to be on guard for threats to our country.
Next.