Website Updated

Submitted by Jeremy
on July 22, 2009 - 12:44am
KernelTrap Changes and News

KernelTrap has been updated to Drupal 6. We're running a fair bit of custom code, so please let me know if you find anything broken or if any of your favorite features are missing. And yes, this upgrade is the first step toward getting regular posts on the website again.

2.6.27-rc8, "This One Should Be The Last One"

Submitted by Jeremy
on September 30, 2008 - 11:55am
Linux news

"So yet another week, another -rc," began Linux creator, Linus Torvalds, announcing the 2.6.27-rc8 Linux kernel. He continued, "this one should be the last one: we're certainly not running out of regressions, but at the same time, at some point I just have to pick some point, and on the whole the regressions don't look _too_ scary. And -rc8 obviously does fix more of them." Linus went on to note that most of the changes since -rc7 are small, "and there aren't even a whole lot of them."

Jiri Kosina cautioned that there is still an unknown bug affecting the e1000e driver currently in the 2.6.27 kernel, "rendering the cards unusable for most of the i-am-not-a-hacker users (and remember, even Dave Airlie bricked his laptop completely to death, when trying to restore eeprom contents)" When asked how to duplicate the bug, Jiri noted that the inability to reliably reproduce the bug added to the difficulty in debugging the problem, "apparently it is some kind of race, as it usually takes multiple cycles to trigger".

Quote: The Real Bug

Submitted by Jeremy
on September 30, 2008 - 11:38am

"The _real_ bug is clearly in the hardware design that allows you to brick those things without apparently even having a lock bit. I'm hoping Intel doesn't treat this as just a software bug. Some hw designer should be thinking hard about which orifice they put their head up in."

2.6.27-rc6, "Things Are Calming Down"

Submitted by Jeremy
on September 12, 2008 - 6:42pm
Linux news

"The patches most people hopefully care about tend to be small details," noted Linus Torvalds, announcing the 2.6.27-rc6 kernel. He continued, "and so more regressions should hopefully be closed now, some by just reverting the commits that caused breakage. I don't think anything special merits explicit comment, but you can get a flavor for things by scanning the appended shortlog." Earlier in the announcement email, Linus did note some specifics about which drivers caused the bulk of the patch:

"Same old deal - except it's been almost two weeks since -rc5. That said, the diff is actually about the same size, so I guess that means things are calming down. Most of the diff (bulk-wise) is updates to the new gspca (standard USB webcam) driver, although some of it is also removal of the dead miropcm20* driver."

Quote: Careful Analysis

Submitted by Jeremy
on September 12, 2008 - 6:31pm

"Some secure protocols like SSH send encrypted keystrokes as they're typed. By doing timing analysis you can figure out which keys the user probably typed (keys that are physically close together on a keyboard can be typed faster). A careful analysis can reveal the length of passwords and probably some of [the] password itself."

Tux3 Acting Like A Filesystem

Submitted by Jeremy
on September 4, 2008 - 11:44am
Linux news

Daniel Phillips noted that his new Tux3 versioning filesystem is now operating like a filesystem, "the last burst of checkins has brought Tux3 to the point where it undeniably acts like a filesystem: one can write files, go away, come back later and read those files by name. We can see some of the hoped for attractiveness starting to emerge: Tux3 clearly does scale from the very small to the very big at the same time. We have our Exabyte file with 4K blocksize and we can also create 64 Petabyte files using 256 byte blocks." He went on to discuss some of the remaining features yet to be implemented, including atomic commits, versioning, coalesce on delete, a version of the filesystem written in the kernel, extents, locking, and extended attributes.

Reviewing the above list, Daniel decided he would work next on the coalesce on delete functionality, noting, "without this we can still delete files but we cannot recover file index blocks, only empty them, not so good." He added that at this time he was only going to focus on file truncation, "as soon as file truncation is added to the test mix we will see much more interesting behavior from the bitmap allocator, and we will discover some great ways to generate horrible fragmentation issues. Yummy." Daniel continued to point out that Tux3 is an open source project, and as such is always looking for others to participate, "whoever wants to carve their initials on what is starting to look like a for-real Linux filesystem, now is a great time to take a flyer. The code base is still tiny, builds fast, has lots of interactive feedback and is easy to work on. And you get to put your email address near the beginning of the list, which will naturally write its way into the history of open source. Probably."

Quote: Every Day, For Fun

Submitted by Jeremy
on September 4, 2008 - 11:39am

"A weak coder becomes a strong coder by reading code and writing code - every day, for fun."

2.6.27-rc5, Fixing Regressions

Submitted by Jeremy
on September 1, 2008 - 10:48am
Linux news

Linus Torvalds announced the 2.6.27-rc5 Linux Kernel, noting that his "weekly releases" tend to happen every eight days, adding, "the bulk of it is all config updates, and with arm and powerpc leading the pack." Linus continued:

"While the config updates amount to about three quarters of the diff, and if you don't use a rename-aware diff the blackfin include file movement pretty much accounts for the rest, hidden behind all those trivial (but bulky) changes are a lot of small changes that hopefully fix a number of regressions.

"The most exciting (well, for me personally - my life is apparently too boring for words) was how we had some stack overflows that totally corrupted some basic thread data structures. That's exciting because we haven't had those in a long time. The cause turned out to be a somewhat overly optimistic increase in the maximum NR_CPUS value, but it also caused some introspection about our stack usage in general. Including things like a patch to gcc to fix insane stack usage for vararg functions on x86-64. But that one would only hit anybody who was a bit too adventurous and selected the big 4096 CPU configuration. The rest of the regressions fixed are a bit more pedestrian."

Quote: Serious Dragons There

Submitted by Jeremy
on September 1, 2008 - 10:39am

"Be careful -- there are some serious dragons there in the presence of multiple threads."

2.6.27-rc4, "Random Stuff All Over"

Submitted by Jeremy
on August 25, 2008 - 5:10pm
Linux news

"Another week, another -rc," began Linus Torvalds, announcing the 2.6.27-rc4 Linux kernel, continuing, "this time the diffstat is almost totally dominated by the addition of the musb driver that drives the MUSB and TUSB controllers integrated into omap2430 and davinci. That, together with the removal of the auerswald USB driver (replaced by libusb version) is more than half of the bulk of the patch, and obviously most users won't ever notice." Linus added:

"Apart from those bulky USB updates, there's some arch updates (blackfin and ia64), network and input driver updates, and an XFS and UBIFS update. The rest is mostly random stuff all over, probably best described by the appended shortlog. A number of regressions should be off the table, but more remain..."

Quote: Good Enough Is Never Good Enough

Submitted by Jeremy
on August 25, 2008 - 5:06pm

"'Good enough' is never good enough ;) What is the ideal implementation? Let's implement that."

AXFS, Advanced Execute In Place Filesystem

Submitted by Jeremy
on August 21, 2008 - 11:10pm
Linux news

"I'd like to get a first round of review on my AXFS filesystem," began Jared Hulbert, describing his new Advanced XIP File System for Linux. XIP stands for eXecute-In-Place. The new filesystem received quite a bit of positive feedback. Jared offered the following description:

"This is a simple read only compressed filesystem like Squashfs and cramfs. AXFS is special because it also allows for execute-in-place of your applications. It is a major improvement over the cramfs XIP patches that have been floating around for ages. The biggest improvement is in the way AXFS allows for each page to be XIP or not. First, a user collects information about which pages are accessed on a compressed image for each mmap()ed region from /proc/axfs/volume0. That 'profile' is used as an input to the image builder. The resulting image has only the relevant pages uncompressed and XIP. The result is smaller memory sizes and faster launches."

Quote: Maybe I'm Overly Pessimistic

Submitted by Jeremy
on August 21, 2008 - 10:53pm

"The C standard will eventually support concurrency (they are working on it), and it will almost inevitably be a horrible pile of stinking sh*t, and we'll continue to use the gcc inline asms instead, but then the gcc people will ignore our complaints when they break the compiler, and say that we should use the stinking pile-of-sh*t ones that are built in.

Git 1.6.0 Released

Submitted by Jeremy
on August 19, 2008 - 7:46am
Tools

"The latest feature release GIT 1.6.0 is available at the usual places," began Git maintainer, Junio Hamano, announcing the latest stable release of the distributed version control system originally written by Linus Torvalds. Among the current changes, Junio noted, "with the default Makefile settings, most of the programs are now installed outside your $PATH, except for 'git', 'gitk' and some server side programs that need to be accessible for technical reasons." He continued, "by default, packfiles created with this version uses delta-base-offset
encoding introduced in v1.4.4. Pack idx files are using version 2 that allows larger packs and added robustness thanks to its CRC checking, introduced in v1.5.2 and v1.4.4.5.
" Julio highlighted several other changes, including the addition of a '.sample' extension to the default trigger scripts to be sure they don't execute in a default install, and the removal of the 'stupid' merge strategy. Other changes include:

"Git-gui learned to stage changes per-line; Reduced excessive inlining to shrink size of the 'git' binary; When an object is corrupt in a pack, the object became unusable even when the same object is available in a loose form, we now try harder to fall back to these redundant objects when able; performance of 'git-blame -C -C' operation is vastly improved; even more documentation pages are now accessible via 'man' and 'git help'; longstanding latency issue with bash completion script has been addressed; pager. configuration variable can be used to enable/disable the default paging behaviour per command; git-cvsserver learned to respond to 'cvs co -c'; 'git-diff -p' learned to grab a better hunk header lines in BibTex, Pascal/Delphi, and Ruby files and also pays attention to chapter and part boundary in TeX documents; error codes from gitweb are made more descriptive where possible, rather than '403 forbidden' as we used to issue everywhere; git-merge has been reimplemented in C."

Quote: Very Hacky Indeed

Submitted by Jeremy
on August 19, 2008 - 7:45am

"The delta cache was really a huge hack that just turned out rather successful. It's been hacked on further since (to do some half-way reasonable replacement with _another_ hack by adding an LRU on top of it), but it really is very hacky indeed."