[ Home | Articles | Account | People | Projects | FAQ ] Name: Russell Coker
Member since: 2001-02-19 14:53:50
Last Login: 2008-04-24 00:59:38
Homepage: http://etbe.coker.com.au/
Notes: I do general Linux programming and sys-admin work. I am mostly known for my work on NSA Security Enhanced Linux.
Smoke from the PSU
Yesterday I received two new machines from DOLA on-line auctions [1]. I decided to use the first to replace the hardware for my SE Linux Play Machine [2]. The previous machine I had used for that purpose was a white-box 1.1GHz Celeron and I replaced it with an 800MHz Pentium3 system (which uses only 35W when slightly active and only 28W when the hard disk spins down [3]).
The next step was to get the machine in question ready for it’s next purpose, I was planning to give it to a friend of a friend. A machine of those specs which was made by Compaq would be very useful to me, but when it’s a white-box I’ll just give it away. So I installed new RAM and a new hard drive in it (both of which had been used in another machine a few hours earlier and seemed to be OK) and turned it on. Nothing happened, I was just checking that it was plugged in correctly when I noticed smoke coming from the PSU… It seems strange that the machine in question had run 24*7 for about 6 months and then suddenly started smoking after being moved to a different room and being turned off overnight.
It is possible that the hard drive was broken and shorted out the PSU (the power cables going to the hard drive are thick enough that it could damage the PSU if it had a short-circuit). What I might do in the future is keep an old and otherwise useless machine on hand for testing hard drives so that if something like that happens then it won’t destroy a machine that is useful. Another possibility is that the dust in the PSU contained some metal fragments and that moving the machine to another room caused them to short something out, but there’s not much I can do with that when I get old machines. I might put an air filter in each room that I use for running computers 24*7 to stop such problems getting worse in future though.
I recently watched the TED lecture “5 dangerous things you should let your kids do” [4], so I’m going to offer the broken machine to some of my neighbors if they want to let their children take it apart.
Release Dates for Debian
Mark Shuttleworth has written an interesting post about Ubuntu release dates [1]. He claims that free software distributions are better able to meet release dates than proprietary OSs because they are not doing upstream development. The evidence that free software distributions generally do a reasonable job of meeting release dates (and Ubuntu does an excellent job) is clear.
But the really interesting part of his post is where he offers to have Ubuntu collaborate with other distributions on release dates. He states that if two out of Red Hat (presumably Enterprise Linux), Novell (presumably SLES), and Debian will commit to the same release date (within one month) and (possibly more importantly) to having the same versions of major components then he will make Ubuntu do the same.
This is a very significant statement. From my experience working in the Debian project and when employed by Red Hat I know that decisions about which versions of major components to include are not taken lightly, and therefore if the plan is to include a new release of a major software project and that project misses a release date then it forces a difficult decision about whether to use an older version or delay the release. For Ubuntu to not merely collaborate with other distributions but to instead follow the consensus of two different distributions would be a massive compromise. But I agree with Mark that the benefits to the users are clear.
I believe that the Debian project should align it’s release cycles with Red Hat Enterprise Linux. I believe that RHEL is being released in a very sensible manner and that the differences of opinion between Debian and Red Hat people about how to manage such things are small. Note that it would not be impossible to have some variations of version numbers of components but still stick mostly to the same versions.
If Debian, Ubuntu, and RHEL released at about the same time with the same versions of the kernel, GCC, and major applications and libraries then it would make it much easier for users who want to port software between distributions and run multiple distributions on the same network or the same hardware.
The Debian Social Contract [2] states that “Our priorities are our users and free software“. I believe that by using common versions across distributions we would help end-users in configuring software and maintaining networks of Linux systems running different distributions, and also help free software developers by reducing the difficulty in debugging problems.
It seems to me that the best way of achieving the goal that Mark advocates (in the short term at least) is for Debian to follow Red Hat’s release cycle. I think that after getting one release with common versions out there we could then discuss how to organise cooperation between distributions.
I also believe that a longer support cycle would be a good thing for Debian. I’m prepared to do the necessary work for the packages that I maintain and would also be prepared to do some of the work in other areas that is needed (EG back-porting security fixes).
Miro AKA DemocracyPlayer
www.ted.com is a premier partner for the Miro player [1]. This is a free player for free online content, the site www.getmiro.com has the player for download, it has binaries for Mac OS/X, Windows, and Ubuntu as well as the source (GPL licensed), it is in Debian/Unstable. It supports downloading in a number of ways (including bittorrent) and can keep the files online indefinitely. A Debian machine connected to the net could be a cheap implementation of my watching while waiting idea for showing interesting and educational TV in waiting areas for hospitals etc [2]. When I first checked out the getmiro.com site it only seemed to have binaries for Mac OS/X and Windows. But now I realise that it’s been in Debian since 11 Sep 2007 under the name Miro and since 12 Jun 2006 under the name Democracyplayer. I have only briefly played with Miro (just checked the channel list) and it seems quite neat so far. I wish I had tried this years ago. Good work Uwe Hermann!
I hope that the Miro player will allow me to more easily search the TED archives. Currently I find the TED site painful to use, a large part of this is slow Javascript which makes each page take an unreasonable delay before it allows me to do anything. I am not planning to upgrade my laptop to a dual-core 64bit machine just to allow Firefox to render badly written web pages.
Biella recently wrote about the Miro player and gave a link to a documentary about Monsanto [3].
One thing I really like about this trend towards publishing documentaries on the net is that they can be cited as references in blog posts. I’ve seen many blog posts that reference documentaries that I can’t reasonably watch (they were shown on TV stations in other countries and even starting to try tracking them down was more trouble than it was worth). Also when writing my own posts I try and restrict myself to using primary sources that are easy to verify, this means only the most popular documentaries.
The Future of Xen
I’m currently in Xen hell. My Thinkpad (which I won’t replace any time soon) has a Pentium-M CPU without PAE support. I think that Debian might re-introduce Xen support for CPUs without PAE in Lenny, but at the moment I have the choice of running without Xen or running an ancient kernel on my laptop. Due to this I’ve removed Xen from my laptop (I’m doing most of my development which needs Xen on servers anyway).
Now I’ve just replaced my main home server. It was a Pentium-D 2.8GHz machine with 1.5G of RAM and a couple of 300G SATA disks in a RAID-1. Now it’s a Pentium E2160 1.8Ghz machine with 3G of RAM with the same disks. Incidentally Intel suck badly, they are producing CPUs with names that have no meaning, and most of their chipsets don’t support more than 4G of physical address space [1]. I wanted 4G of RAM but the machine I was offered only supported addressing 4G and 700M of that was used for PCI devices. For computation tasks it’s about the same speed as the old Pentium-D, but it has faster RAM access, more RAM, uses less power, and makes less noise. If I was going to a shop to buy something I probably would have chosen something different to get support for more than 4G of RAM, but as I got the replacement machine for free as a favor I’m not complaining!
I expected that I could just install the new server and have things just work. There were some minor issues such as configuring X for the different video hardware (and installing the 915resolution package (which is only needed in Etch) to get the desired 1650×1400 resolution. But for the core server tasks I expected that I could just move the hard drives across and have it work.
After the initial install the system crashed whenever I did any serious hard drive access from Dom0, the Dom0 kernel Oopsed and network access was cut off from the DomU’s (I’m not sure whether the DomU’s died but without any way of accessing them it doesn’t really matter much). As a test I installed the version of the Xen hypervisor from Unstable and it worked. But the Xen hypervisor from Unstable required the Xen tools from Unstable which also required the latest libc6, and therefore the entire Dom0 had to be upgraded. Then in an unfortunate accident unrelated to Xen (cryptsetup in Debian/Unstable warns you if you try to use a non-LUKS option on a device which has been used for LUKS and would have saved me) I lost the root filesystem before I finished the upgrade.
So I did a fresh install of Debian/Unstable, this time it didn’t crash on heavy disk IO, instead it would lock up randomly when under no load.
I’ve now booted a non-Xen kernel and it’s working well. But this situation is not acceptable long-term, a large part of the purpose of the machine is to run virtualisation so that I can test various programs under multiple distributions. I think that I will have to try some other virtualisation technologies. The idea of running KVM on real servers (ones that serve data to the Internet) doesn’t thrill me, Tavis Ormandy’s paper about potential ways of exploiting virtual machine technologies [2] is a compelling argument for para-virtualisation. Fortunately however my old Pentium-3 machines running Xen seem quite reliable (replacing both software and hardware is a lot of pain that I don’t want).
In the near future I will rename the Xen category on my blog to Virtualisation. For older machines Xen is still working reasonably well, but for all new machines I expect that I will have to use something else - and I’ll be blogging about the new machines not the old. I expect that an increasing number of people will be moving away from Xen in the near future. It doesn’t seem to have the potential to give systems that are reliable when running on common hardware.
Ulrich Drepper doesn’t have a high opinion of Xen [3], the more I learn about it the more I agree with Ulrich.
Offensive Blog Posts
There has been ongoing debate in the Debian community for a number of years about what standards of behavior should be expected. Matthew Garrett sets a new low by making a joke about Jesus being molested as a child [1]. While I believe that debate and discussion about religion is a good thing, such comments about someone who is widely regarded as a God (part of the Holy Trinity) seems to provide no value and just needlessly offends people. I used to be a Christian, and while I have great disagreements with most Christians about issues of religion I still believe that Jesus (as described in the bible) was a good person and deserves some respect. I don’t believe that blasphemy should be illegal, but some minimum standards should be observed when discussing religion.
Next there is the issue of child molesting, most people agree that there’s nothing amusing in that - so I hope that nothing more needs to be said about violating babies.
Finally there is the issue of rape in general often being treated as a joke in the computer industry (I am not sure how prevalent this is in the wider community). One example that is from a Wired article: “We were raped by Microsoft. Bill Gates did it personally. Introducing Gates to the president of a small company is like introducing Mike Tyson to a virgin” [2]. I admit that finding examples of this on the web is not easy, part of it is due to such slang use being more common in spoken communication than in written communication, another is the vast number of slang terms that are used.
A Google search for “male rape” [3] turns up some informative articles. One FAQ suggests that 3% of men will be raped as an adult [4] - I expect that some guys will decide that it’s not so funny when they realise that it could happen to them.
For people who’s knowledge of the English language is not as good as that of Matthew and I, here is the dictionary definition of the word “violated” [5].
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