Recent blog entries for davej

cheap usb memory sticks & livecds.

This seems ridiculously cheap.
A number of times in the last week I've ordered stuff from amazon where the shipping has cost more than the item. (I have amazon prime, so get free shipping, but this doesn't work for 3rd party sellers using Amazon as a storefront).

Curiosity got the better of me, and even with the shipping making it ~$10, it still seemed like a great deal for 4GB, so I ordered one. The Fedora livecd-iso-to-disk script makes it pretty simple to create a bootable usb stick preloaded with Fedora. 4GB is a pretty usable amount of space. (It's that same that I had on my first eeepc, which proved more than adequate). Hopefully it's not something substandard with a low number of write-cycles, or slow speed or the like. I guess I'll know in a week. If this works out though, I think I'll never have to bother carrying a rescue CD with me every time I travel.

Syndicated 2008-10-04 20:29:59 from Dave Jones recollection of stuff that happened.

bugtrackers and lots of comments.

Some things I'd really love to see to improve the usefulness of bugzilla (and other bugtrackers)

• Comment nesting.
  Basically multiple "Reply to this comment" buttons, one after each post, instead of one "post a new comment" button.
  
• A "collapse this thread in *my* view of this bug".
  Useful for ignoring inconsequential stuff that people may post to the bug. "HEY! I SAW A KERNEL OOPS ONCE TOO!"
  
• (going a bit crazy now). Comments Points/Moderation/Scoring.
  Vote down a comment so it gets auto-collapsed in everyones view of the bug.
  

(This is beginning to sound like the bastard child of bugzilla & digg/slashdot, so I'll stop here).

I've had these thoughts a few times over the last few years triaging kernel bugs for Fedora. I think they would be worth additions especially for the instances of a single bug that gets many people jumping on it. Especially high profile issues like the current e1000e scare that has a bunch of people worried.
(Though the Fedora bug tracking that problem is quite tame in comparison to the ubuntu one right now. I actually pity those guys having to wade through all those comments, with so much not-directly-useful-or-relevant commentary).

But we've had issues in the past in Fedora where we've easily had over 100 comments. Trying to keep up with what's going on when there are 16 different people all with slightly different (or even completely different in some cases) problems is nearly impossible after a point. On a number of occasions, I've just closed the bug with a comment along the lines of "guys, this is madness, please file individual bugs, and we'll work through them".

Part of the problem is context. If all I had to do was look at that one bug, and work on it, it wouldn't be such a big deal. Due to there being more bugs than developers (in any distro), time-slicing occurs, and regaining 'state' when loading up a bug again takes a while. When there's pages and pages of comments, it's sometimes impossible to regain the full picture just due to the amount of noise.

Syndicated 2008-09-24 22:54:16 from Dave Jones recollection of stuff that happened.

initrd clarifications.

After reading some of the comments at lwn about my sessions last week at kernel summit/plumbers conf about writing a 'make initrd' target for the kernel that would work on every distro, I feel some clarifications are in order.

What I am not doing.

• Dropping the Fedora mkinitrd script into the kernel.org tree and hoping other distros will make it work for them.
  
• Obsoleting the existing mkinitrd from Fedora for a considerable amount of time. (Think RHEL7 timeframe).
  

What I am doing.

• Right now, nothing but decompressing. Last week was pretty intense, with a lot of feedback to take in.

What I've done

• I've looked at other distros initrd's & creation tools. They all suck equally. Really. If you disagree, you either haven't looked hard enough, or you have emotional attachment issues. There is really nothing amazing about your distros tools over any others. (Which is why I'm of the opinion that "do it right, once, upstream" is the right answer.
  
• Written very little code. A few dozen lines of shell on the planeride home. I'm not posting anything until it at least is limping[1] along.
  

What I'll do next

• Yes, I'm starting afresh. I'll be borrowing some bits from various distros initrd's as I stumble into "hmm, how _does_ this currently work" territory, but this is going to be done with baby steps, first of all just booting off simple setups with /dev/[hs]da, no root on nfs/iscsi/nbd etc.
  
• At least in part, I'm starting with something completely new for political reasons. It's the only way to get anyone to agree on how to make progress. With everyone so invested in their current working solutions, "just use the debian one" or "just use the fedora one" isn't going to get us anywhere.
  

How is this going to work?

• For Fedora systems, we'll be building an additional initrd. Currently we only build it at kernel RPM install time, tailored for that system. Going forward, a one-size-fits-all initrd will be made during the package build process. Which gets used will depend on an /etc/sysconfig/kernel/ setting. This way, we can continue to use the crufty mkinitrd until this thing is ready, and the bleeding edge lunatics and people actually wanting to work on this can set the variable and have the new hotness.
  
• The very first step however is recovering from some of the fallout of the boot/init session of plumbersconf. Reviewing our CONFIG options. It's likely that use of 'make initrd' will imply that certain options should be set certain ways.
  

Once I'm feeling a little more on my feet[2], I'll make some more posts on what I intend to do, and how. Until then, continue to speculate wildly.


[1] Trapped sciatic nerves are the _worst_.
[2] Seriously. Screw flying anywhere for a while. I'm staying home.

Syndicated 2008-09-22 19:38:43 from Dave Jones recollection of stuff that happened.

bandwidth limit.

Just got this mail from comcast..


On October 1, 2008, we will post an updated AUP that will go into
effect at that time.

In the updated AUP, we clarify that monthly data (or bandwidth) usage
of more than 250 Gigabytes (GB) is the specific threshold that
defines excessive use of our service. We have an excessive use policy
because a fraction of one percent of our customers use such a
disproportionate amount of bandwidth every month that they may
degrade the online experience of other customers.

250 GB/month is an extremely large amount of bandwidth and it's very
likely that your monthly data usage doesn't even come close to that
amount. In fact, the threshold is approximately 100 times greater
than the typical or median residential customer usage, which is 2 to
3 GB/month. To put it in perspective, to reach 250 GB of data usage
in one month a customer would have to do any one of the following:

* Send more than 50 million plain text emails (at 5 KB/email);
* Download 62,500 songs (at 4 MB/song); or
* Download 125 standard definition movies (at 2 GB/movie).


I guess I won't be syncing rawhide packages on a daily basis any more.
Or doing complete package tree checkouts.

I wonder what other bandwidth excesses I take for granted I'll have to cut back on.

Syndicated 2008-09-13 21:22:35 from Dave Jones recollection of stuff that happened.

NIN live visuals running on Linux.

'all the onscreen video is rendered by Moment Factory's custom rig, a trio of Linux-based devices collectively known as "the brain.".'

And for the record, that light show kicks so much ass. Some truly impressive effects. Some of which are on youtube, but cellphone captures really don't do them justice. If you get the chance to see this tour, even if you aren't a huge NIN fan, I really recommend it. I remember 20 years ago, people were saying similar things about Pink Floyds lightshows. This is all that, and so much more. (And apparently still being refined/enhanced, making me eager to see them again. Vegas at xmas maybe?)

Also, that wired article has confirmation that the 'nine inch fail bsod was intentional. Well duh.

I'm curious to find other stuff the moment factory guys have been responsible for. They're based in Montreal. Maybe we can get them to keynote next years OLS :)

Syndicated 2008-09-13 15:51:00 from Dave Jones recollection of stuff that happened.

back.

Was on vacation last week in San Francisco, which was pretty awesome. A really fun city with a lot to see and do. Good to catch up with a few people, and also good to play tourist and go do touristy things (like visiting Alcatraz). Highlight of the trip by far though, was seeing Nine Inch Nails live at Oakland colliseum.

The low point of it all, was I seemed to somehow do myself an injury. When I arrived, I was aching a lot, but I put it down to just the usual cramped airplane flight, and then walked around SF, a lot. Including (not one my brighter moments) up some pretty harsh hills.
By the time Saturday came around, I couldn't stand up for too long without back/leg ache. Then I flew home yesterday in complete agony. The over the counter painkillers I got did pretty much nothing. By the time I got back to Boston, I was hobbling along with all my luggage at some ridiculously slow pace.

I hardly slept last night due to the discomfort. First thing this morning, I went to the ER to get checked out. Got poked and prodded a lot, and the best they could come up with was "probably a trapped sciatic nerve". So they loaded me up with percocet,valium and ibuprofen and sent me home. I took some, and headed back on the T. About halfway into my journey, I think they kicked in, because I spaced out, and completely missed my stop. They make me feel kind of drunk.
Got off, and had some lunch, and resumed my trip home.

So, great start to my first day back at work. I'm ridiculously backlogged from email right now, so will spend most of this week catching up, and taking it easy in the hope that I'm over this injury before the weekend when I'm due to fly to Portland,OR for kernel summit/plumbers.

[apologies if any of the above sounds somewhat more incoherent than usual, seriously, these drugs are making my brain do funny things]

Syndicated 2008-09-08 18:20:12 from Dave Jones recollection of stuff that happened.

lockdep lolz.

My entry for the "most extensive debug output from a single event" world record.

.. and with that, I'm off on vacation for a week.

Syndicated 2008-09-03 00:37:01 from Dave Jones recollection of stuff that happened.

Open source noise machines.

this is pretty cool.
I'm an avid collector of effect units (I lost count a while back just how many I have). Having something tweakable in this manner is kind of neat. Though I don't think I'll be getting one for a few reasons.

First, I use my noise-making as an escape from open source. Sometimes, even I need to switch off, and moving to a different room to run gdb in a different use-case isn't really escaping.

Secondly, since the beginning of the year I've been building a modular analog synth. The beauty of this thing is it's pretty much entirely open. Want more oscillators? fine, buy some, screw them in. Extra filters? same deal. Once you have a collection of mounted modules, you then get a large number of possible patch combinations between the various modules. For many of the modules, people have even made various 'hacks' to improve them in some manner or other. The manufacturers have in some cases even adopted those changes in later revisions of modules which is really awesome.

Whilst as a synth, it's primarily for the creation of sound, it also works really well as a sound-mangler of any input source, making it a supe r guitar effects pedal on steroids. And with cool sounding modules like "malgorithm", I'm easily persuaded.
The nice advantage of analog gear is that it rarely goes wrong in the sense that computers do. It frequently does completely unpredictable things, but it's usually a 'happy accident' than a complete disaster.

The only downside is these things get to be habit forming, and start to take over the house. Mine has already
grown to twice the size I was initially expecting, and will probably increase some more before I'm "done".

I keep meaning to record some of the output of this and other devices. One of these days I'll get to it. Until then, just imagine mains hum modulated by howling feedback with sub-bass that makes the walls shake, and you're probably pretty close to the sorts of sonic mayhem this thing puts out. (It's not /all/ it can do, it's just what I tend to make it do a lot).

Syndicated 2008-08-27 17:00:13 from Dave Jones recollection of stuff that happened.

Highlighting.

I'm a big fan of highlighting text. (But only on computer screens, I hate highlighters on paper, and really don't understand those people who selectively highlight semi-random parts of books). To this end, I have the usual things set up, like my .vimrc enables syntax highlighting to show me when I've forgotten what C should look like. I've also started extending it to other uses. Like highlighting common bugs. It turns out to be handy when both writing code, and reviewing other peoples.

It's pretty simple to do in vim. For example..

highlight kmalloc ctermbg=red guibg=red
match kmalloc /k[mzc]alloc(GFP_/

highlight memset ctermbg=red guibg=red
match memset /memset.*\,\(\ \|\)0\(\ \|\));/


Now, go ahead and try that zero sized memset. Or a kmalloc with swapped arguments. The bright red text screaming AWOOGA in your face should be attention grabbing enough for you to instantly realize what's up as soon as you've written the erroneous line of code.

The above regexps aren't new either. I've posted blog entries before about how I recursive grepped for the latter across all 80gb of the Fedora source tree periodically. (And it still keeps turning up new casualties).

I've also extended mutt to catch this nonsense.


color index red default '~b "memset.*\,\(\ \|\)0\(\ \|\));"'


When paging through my inbox, when I see a mail in red, I know there's something silly in it, which needs further review. (Very handy for reading things like commit mailing lists, or code review lists).

Even if you don't write C, there are probably regexps for catching API misuses in other languages too, so the above principles should be useful. (I use vim/mutt almost exclusively, no idea how to make highlighting work with emacs etc, but I'm sure it's doable there too).

Syndicated 2008-08-27 16:44:52 from Dave Jones recollection of stuff that happened.

My ass has a carbon footprint.

I've really enjoyed not traveling anywhere this last month. As much as I like seeing different places, I really enjoy being back home. I find that miss the little things. I miss having a routine.
Next week sees the restart of lots[*] of traveling.

Beginning with a vacation. I'm in San Francisco from next Wednesday through Sunday. (locals: drop me a mail if you'd like to meet up for a food/beer or whatever.) I've got stuff planned for most the week, but there's guaranteed to be a bunch of free time too. On Thursday I'm off to Alcatraz for a few hours, which should be interesting. And on Friday night, I'm heading over to Oakland to see Nine Inch Nails which should be good fun. (if any locals I know are also going, send hot mailz. I need knowledge on how to survive Oakland without getting stabbed/shot/etc. Teach me your survival skills.)

Assuming I survive my outing to Oakland, I get back to Boston on Sunday evening, and get a whole week at home, before heading back out to the west coast again, this time to Portland, Oregon for the Linux kernel summit, and plumbers conf. I'm giving a talk there on how much of an awesome idea it would be if every Linux distro shipped a standard initrd. It's either going to be awesome, or a lead balloon.

[*] ok, it's not "lots", but two coast to coast trips in the same month are still what I deem 'excessive'.

Syndicated 2008-08-26 23:00:59 from Dave Jones recollection of stuff that happened.