Yesterday s
RAM mystery was
solved after dozens of people have written in with helpful
comments. Thank you all. I
need to find time to create a
proper, commentable blog soon so that you all can get the credit
you deserve!
I now have the full 4GB of RAM available:
$ free head -2
total used free shared buffers cached
Mem: 4063324 1657440 2405884 0 149080 643732
Yay!
The suggestions ranged from timing issues to defective modules,
from 64bit OS via south/north bridge limitations to sacrificing
chickens to god spongebobs.
In the end, several people put their finger on a concept called
memory hole remapping , and that turned out to be the ticket. Here
is what I learnt:
This motherboard and the CPU memory controller supports (which
means can address ) 4096MB of RAM. Since extensions cards, such as
the graphics card and the network controller, also need addressable
slabs of memory for their RAM or registers, ranges in the upper
memory regions are mapped to the RAM of those cards.
The file
/proc/mtrr gives a clue over what s
happening:
reg00: base=0x000000000 ( 0MB), size= 2048MB, count=1: write-back
reg01: base=0x080000000 ( 2048MB), size= 1024MB, count=1: write-back
reg02: base=0x0c0000000 ( 3072MB), size= 256MB, count=2: write-combining
reg03: base=0x0d8000000 ( 3456MB), size= 128MB, count=1: write-combining
reg04: base=0x0e8000000 ( 3712MB), size= 64MB, count=1: write-combining
reg05: base=0x0ec000000 ( 3776MB), size= 64MB, count=1: write-combining
Registers 0 and 1 represent the addressable RAM available to the
operating system. At position 3072, we find two slabs of 256MB
each, most likely corresponding to the two graphics cards in the
system. I
think that the 128MB in register 3 is the AGP
aperture. Registers 4 and 5 correspond to 64MB slabs each, most
likely relating to the two network cards I have installed.
The result is that addresses in memory beyond 3072MB are
routed to the extension cards, which overshadow the original
system RAM and leave it unusable.
When I turned on the memory hole remapping feature in the
BIOS, I empowered the BIOS to remap the memory space. The way it
does this is BIOS-dependent, but most likely, it will remap the
overshadowed memory region to the end of the total memory space.
This is a software-only remapping, but the effect is that the
system appears to have more memory.
/proc/mtrr now reads:
reg00: base=0x000000000 ( 0MB), size= 4096MB, count=1: write-back
reg01: base=0x100000000 ( 4096MB), size= 1024MB, count=1: write-back
reg02: base=0x0c0000000 ( 3072MB), size= 1024MB, count=1: uncachable
reg03: base=0x0c0000000 ( 3072MB), size= 256MB, count=1: write-combining
I am not entirely sure how to interpret this yet, but you can
see that there are now an additional 1024MB at position 4096
(register 1), so the system seems to have 5GB of RAM available.
Register 2 describes memory between 3072 and 4096 as not cacheable,
because it maps to extension cards. I do not know how register 3
fits into the picture.
By remapping, we cross the 4096MB mark. To make use of the
additional memory, we will need
PAE
enabled to give you 36 bits, or a 64bit operating system: 2^32
is 4096M, so with only 32 bits available, 4GB is all the memory
that can ever be addressed (dirty hacks excluded). Fortunately,
this system has been running the
Debian amd64 port even
before it was officially released, and thus, once the BIOS remapped
the memory, I could fully make use of it.
Mystery solved, some knowledge acquired, many of you left to
thank!
Many moons ago while doing fieldwork I went to a radical tech activist camp sponsored by The Ruckus Society to give a presentation on Free Software (which I actually still have online in the gaudy orange I so loved. I could only stay 2 days as I had to go to Debconf2 in Toronto for fieldwork but it forever changed my life in pretty significant ways.
One remarkable thing about Ruckus was that for the first time I meet a particular kind of geek I had yet to come across: the crunchy and chewy granola/environmentalist/hippie hacker a type of hacker that can be found world over but is likely to be (unsurprisingly) living, sometimes in the trees (literally) in the Pacific Northwest. They are one of my favorite kind of people as I can talk endlessly to them about 2 of my great passions: Free Software and environmental justice. Comfrey, pictured above, was one such hacker from Portland who I met at the Ruckus event and now routinely shows up, usually unannounced to our house at least 1-2x a year.
I woke up this morning to find him on our couch, got a bunch of knot-weed to chew on compliments of his foraging, and took the afternoon off to share some food. Among many stories, he told me of a new transportational pursuit of his, Roller-Hitching, which he uses to get around the country. He uses old school roller skates to skate along the road, even highways, until he gets picked up and get where he needs to go.
Naturally, these old school states are not just functional in the sense that they are faster than two feet in motion, but since they signify a particular spirit of the 1970s you know, the groovy, dynamite, free love spirit of things, they draw positive attention and apparently when he roller-hitches, he gets picked up frequently (and made it from Minneapolis to Portland in 2 hours and 2 days: not shabby).
In California while on the 101 north of Arcata, California, Comfrey got stopped by the highway patrol and basically the cop wanted to kick him off on the grounds the he was a pedestrian (apparently prohibited on this patch of the 101). Comfrey, being a bright fellow, basically noted that roller skating is not really a pedestrian activity, that he was using, much a like a biker, a transportation device of sorts, so that he was in a grey zone between bikes and walking.
At the time, the cop was convinced enough but did tell Comfrey to look up the law in the library cuz the next time he would give him a ticket and the next time after that throw him in jail. Comfrey has yet sourced the law but soon will. When he does, since I like to report on geeks and the law, I too will report on whether one can roller skate down or up the highway for those that might want to give Roller-Hitching a try.
Such was the scene I arrived at on Wednesday last week at the municipal health center at Kyll , Jyv skyl , Finland. A queue extended a hundred meters beyond the door. It was not hard to guess what it was about, as it had been announced that the pandemic influenza A/H1N1 vaccine would be administered there to people in specific risk groups from 10 am to 3:30 pm.
I should explain here the Finnish health care setup. There are three parallel systems a comprehensive public health care system maintained by the municipalities to standards set by the state, a network of private for-profit health care providers, and a national foundation dedicated to university student health care. Employers are required by law to provide a minimal level of health care to their employees, and most of them also provide, free of charge to the employees, access to near-comprehensive general-practice-level care; most employers buy this service from the for-profit providers. The public system suffers from resource starvation at the general-practice level but provides excellent care in the central hospitals that handle the difficult cases.
Anyway, the H1N1 vaccine is only available through the public system and through the foundation free of charge if you qualify for the vaccine, and no amount of money buys it for you in this country if you don t. Thus, I and many others, normally cared by the employee services, found ourselves queuing up at a public health care institute. And clearly, the public health care system was overwhelmed on that first day.
When I entered the queue, its tail was a traffic hazard. Fortunately, the queue moved faster than new people arrived thereafter, and the hazard ended. The queue moved surprisingly fast it took me one hour to advance the 100 meters to the door. Even so, this was a failure in the system there is no good reason to have people with underlying illnesses (and we all had them, to qualify for the vaccine) stand around in freezing cold weather for an hour!
Once, a nurse came and asked us if any of us was 63 years old or older. Apparently no-one was, since no-one was asked to leave (they will be vaccinated later). Later, another nurse asked everyone in the queue outside to show their KELA cards KELA is the national health insurance system, and its card carries information about extra coverage one qualifies for due to underlying illnesses.
Eventually, I reached the door. Two guards stopped anyone who tried to enter directly, sidestepping the queue, and let in only those who had legitimate business other than vaccination. The main hall was full of people, and I quickly realized that the queue took a full circle inside the hall to reach the multiplexing point. It took me another hour to slowly advance my way though the hall. At the multiplexing point, I was asked to wait a bit, and then I was assigned a vaccination room and a waiting number.
Some twenty minutes later I was called in. The vaccination room I was assigned to was a nurse s office. Two nurses were there, one who would administer the vaccine, and another at the computer, to keep a record. I gave them my KELA card, and shed my coat and my outer shirt, and bared my left shoulder. I was quickly given the pandemic vaccine; there was no question I was qualified for it, not with my obesity being obvious.
Then they asked what my diagnosis was. Prmarily I m here because of my obesity, I said. But I also have paroxysmal atrial fibrillation.
That s not what your KELA card says, accused the nurse at the computer.
The diagnosis is so new, I countered. There has been no time to do the paperwork for KELA. (And indeed, I later learned, it would come up in my next checkup in the spring.)
They stared at each other.
I can show you my prescriptions, I said, making no move for them.
Stares.
I stared back.
Do you want the seasonal vaccine or not? asked the nurse with the injectors.
I lauged briefly. I might as well. It had, honestly, never crossed my mind that I might qualify.
She injected me on my right shoulder. You should stay in out there for ten minutes.
I picked up my clothes and found the cafeteria with coffee and pastry.
Then the real fun started. Next day, I woke with horrible upper back pain. The thermometer showed mild fever; but since i didn t have any respiratory symptoms, I decided to go to work. In the evening, turning in bed was excruciatingly painful. It took days for the pain to subside.
I left the building three hours after I arrived at the end of the queue. What? You think that s excessive? So do I and many others; queuing feels so Soviet Union! But honestly, while it did take time, it worked. I am vaccinated; are you?
Whew!
Is it karma or what? What makes me get involved in two horribly complex, two-week-long conferences, year after year? Of course, both (DebConf and EDUSOL) are great fun to be part of, and both have greatly influenced both my skills and interests.
Anyway, this is the fifth year we hold EDUSOL. Tomorrow we will bring the two weeks of activities to an end, hold the last two videoconferences, and finally declare it a done deal. I must anticipate the facts and call it a success, as it clearly will be recognized as such.
One of the most visible although we insist, not the core activities of the Encounter are the videoconferences. They are certainly among the most complex. And the videoconferences' value is greatly enhanced because, even if they are naturally a synchronous activity (it takes place at a given point in time), they live on after they are held: I do my best effort to publish them as soon as possible (less than one day off), and they are posted to their node, from where comments can continue. This was the reason, i.e., why we decided to move at the last minute tomorrow's conference: Due to a misunderstanding, Beatriz Busaniche (a good friend of ours and a very reknown Argentinian Free Software promotor, from 
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The easiest way of reproducing this scenario is as follows:
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I know it has been a long time since my last post. I am sorry about that, but life has it s complications every now and then (as you know)... Well, on to the article.
Recently I had to reimplement in C a prefork server I wrote in Ruby for an internal project at