Chris Tyler's Blog - Seneca Planet

ARM Spam!

nospam@example.com (Chris Tyler) — Thu, 05 Aug 2010 11:50:48 -0400

My apologies to anyone experiencing a large volume of build notifications from the fedora-arm koji system. We're attempting to build F13 and are experiencing a lot of build failures (as expected).

I've added some dependency checking to the build script (big thanks to Seth Vidal for the yum code snippets!) which should make it a bit smarter about build order. Build notifications have been turned off until we get the failures down to reasonable levels.

Come and Speak at FSOSS 2010

nospam@example.com (Chris Tyler) — Wed, 21 Jul 2010 22:24:09 -0400

The 9th Annual Free Software and Open Source Symposium (FSOSS, "eff-sauce") is coming up on October 28th and 29th, here at Seneca College in Toronto. This is a great event with a wide-ranging, eclectic mix of workshops and presentations.

I've been involved in planning FSOSS for the past few years, but stepped back a bit to catch my breath this year. Mary Lynn Manton has stepped up to the task of chairing this year's event with Rose Saliba, who is co-chairing for her third year.

FSOSS is still looking for interesting workshops and presentations on a variety of open source topics. If you're working with open source in any way, this could be a great opportunity -- please check out http://fsoss.ca and submit a presentation proposal right away!

Fedora 13 Release Event

nospam@example.com (Chris Tyler) — Sat, 19 Jun 2010 10:51:52 -0400

Fedora 13 was release a few weeks ago. We're going to celebrate the release at a release event in Toronto on July 5th. Here are the details:

Who: Fedora Community -- and anyone interested!
What: Fedora 13 Release Event
Where: Seneca@York, TEL Building, room T1009
When: Monday, July 5, 6 pm
Why: To celebrate the release of Fedora 13 "Goddard", distribute Fedora 13 discs and discuss its new features, and meet up with other Linux contributors and users
Wiki URL: http://bit.ly/f13-toronto

Please join us if you're interested. I hope to see you there!

Sugar on a Stick - Activities

nospam@example.com (Chris Tyler) — Thu, 17 Jun 2010 11:44:44 -0400

Sugar on a Stick is a project which aims to create a live learning environment on a USB stick. This environment is a Fedora spin hosting the Sugar environment (the learning software original created as part of the OLPC project).

In previous versions of SoaS, the activities were not thoroughly screened before inclusion in the Spin, and so the SoaS Activity Criteria were introduced. I've been working with some other POSSE RIT participants to try and get three activities - Abacus, Maze, and Memorize - to the point of meeting the criteria. It's been a frustrating experience, but we've made some progress:

Abacus

Performed a package review (not passed, but close) of Peter Robinson's sugar-abacus package in Fedora
Created a basic page for recording smoke test results

Maze

Filed a bug against the sugar-maze package in Fedora (apparently missing an essential .py file)

Memorize

This activity meets most of the criteria, but we weren't able to save to the journal (know issue) and could not confirm that collaboration works (might have been our Sugar configuration or networking)

It's apparent that the Sugar project needs more contributions, including wiki gardening, testing, and documentation -- all of which are areas in which new contributors can become quickly involved.

WebM - Open video & audio - in Fedora 14?

nospam@example.com (Chris Tyler) — Wed, 19 May 2010 13:18:28 -0400

HTML5 provides <audio> and <video> tags for sound and video content. However, every browser seems to support a different combination of codecs and containers for these tags. Open source projects have of necessity only been able to support open formats, but proprietary vendors have been reluctant to throw their weight behind those open formats.

At GoogleIO today, Google, Mozilla, Opera, and 30+ other partners announced WebM, an open source mashup of the Matroska container format, Vorbis audio codec, and newly-open-sourced VP8 video codec. The intention here is to provide a "safe", open-patent-grant format that both open source and proprietary products can integrate. To that end, the WebM code is licensed under a BSD + patent grant license. And, of course, with Google/YouTube supporting this format, there will be a lot of content available.

So how does this touch Fedora? It looks like current Firefox nightles support WebM, and gstreamer support is in the works; hopefully, this will land in time for Fedora 14. For rpmfusion/ffmpeg users, WebM support is in today's upstream ffmpeg release.

Mozilla running Unit Tests on Fedora

nospam@example.com (Chris Tyler) — Wed, 19 May 2010 08:49:20 -0400

Mozilla uses CentOS for their Linux builders. They have up to this point also been running their unit tests on CentOS, but Armen has now switched the Linux unit tests over to 32- and 64-bit Fedora. This is a great win, because it means that Firefox will be tested against a more-current environment.

Fedora-Advisory-Board

nospam@example.com (Chris Tyler) — Thu, 22 Apr 2010 20:04:16 -0400

Within the Fedora project, there is a mailing list that perhaps doesn't get as much attention as it should: advisory-board. The name itself seems a bit cryptic, but this is the place that the Fedora Project Board has public discussions. It's the place where board proposals get hashed out in public, and it's a good place to bring items to the attention of the board. Come and join the conversation!

Network Storage: Loopback ext3 on NFS? Really?

nospam@example.com (Chris Tyler) — Thu, 22 Apr 2010 13:57:21 -0400

One interesting find I made while working with the Seneca students on Fedora ARM was that a loopback filesystem hosted on top of an NFS share can outperform the NFS share. Yes, it's counter-intuitive, because that would seem to introduce additional layers of processing, but I think it makes sense.

When using NFS, file metadata management is performed by NFS. When loopback-mounting a filesystem in a file hosted on NFS, the file metadata management takes place entirely on the local system -- NFS merely provides a data store. In this sense, it's not much different from iSCS, because the loopback filesystem can't be readily accessed by two separate hosts at once.

In fact, on a small ARM system such as an OpenRD-Client, loopback-ext3-on-NFS over GigE handily outperforms both Class 6 SD and a local USB-PATA drive.

Why not just use iSCSI? Well, for reasons I haven't yet determined, the Fedora iSCSI initiator doesn't work reliably on ARM-- under heavy load, it sends invalid opcodes to the target. This sounds like an alignment issue, but alignment fixups don't cure it. Investigation continues...

Seneca and the Fedora ARM Secondary Architecture

nospam@example.com (Chris Tyler) — Thu, 22 Apr 2010 11:04:20 -0400

ARM processors power the digital mobile age. Billions are produced per year, ending up in the majority of cellphones as well as in e-book readers, plug computers, the OLPC XO 1.75, tablets, netbooks, intelligent RJ-45 network jacks, and even microSD cards.

The Fedora ARM Secondary Architecture project has done a great job of porting Fedora releases to ARM. To assist this initiative, this semester's Software Build and Release course at Seneca (SBR600) put together a new Koji build farm for the ARM architecture in preparation for using koji-shadow to follow the primary architectures. It's been a fascinating and challenging project -- working with cross-compilers, emulators, and hardware with much smaller configurations than standard PCs. A large amount of effort was spent benchmarking various configurations to determine optimal memory and storage arrangements and to compare emulated vs. hardware ARM performance to guide the configuration of the build farm.

So now we're at the end of the semester. Where do things stand?

We have a working Koji build system, with two hardware builders plus emulated (VM) builders
Since we're at the end of the semester, things will be quiet for the next week and a half, but then we've hired a graduate to work on this full-time (intros coming up shortly )

What's next? In May-June we expect to:

set up FAS2 certs
add 10+ hardware builders
implement koji-shadow

Do you have important data or software on CDOT machines?

nospam@example.com (Chris Tyler) — Thu, 08 Apr 2010 21:46:14 -0400

We're about to reconfigure a number of machines in CDOT. If you have any critical data on these machines, you need to back it up or move it before exam week (April 18).

These machines will be updated (new disks) and/or reinstalled and/or moved:

Germany
Liberia
China
India
Russia
EasterIsland
Spain
Canada

These machines will not be reinstalled (yet), but will probably be moved:

Scotland
Ireland
HongKong
Australia

...but even on those machines, it would be a great idea to back up your stuff!

Customer, not Criminal

nospam@example.com (Chris Tyler) — Thu, 11 Mar 2010 00:22:36 -0500

I like TigerDirect stores: they're like geek supermarkets. However, they have some really annoying practices, such as entering my card number into their POS system, separately from their POS terminal; the terminal receipt shows only the last 5 digits of the card number, and the cash register receipt shows all but the last 6 digits. Anyone with those two receipts and the Luhn algorithm has the full card number.

But the practice that annoys me the most is having a person at the door "check the receipt" of each person making a purchase. The receipt-checker is standing only a few meters away from the cash register -- what is there to check? Is this an effective loss-prevention practice, or just a way to annoy customers?

Today I bought a micro-SD flash card with adapter for an Open-RD Client system that Seneca just purchased. The sales guy was helpful, and as I took the purchase to the lone cashier on duty, I found her talking to the receipt-checker. She shuffled over to the cash register. I paid and made my way to the door, and the receipt checker smiled at me and popped the top off his blue highlighter. I smiled back.

"May I check your receipt?" he asked.

"No," I answered, continuing to the door. I figured that the purchase has already been made, as far as I know they have no right to search or detain me, the receipt checker saw me pay the cashier, and it's obvious that I have one purchased item and one receipt in my hand.

Thinking he'd heard wrong, he again asked, "May I check it?"

"No," I replied, walking out.

"Thank you," he yelled after me as I left the store.

Running Fedora-ARM in emulation under virsh

nospam@example.com (Chris Tyler) — Thu, 04 Mar 2010 14:30:09 -0500

The Fedora qemu-system-arm package provides pretty good ARM processor emulation, which can be used to run the Fedora ARM secondary architechture. This is an easy way to get started working with ARM -- for example, while waiting for your plugcomputer, beagleboard, or OLPC XO 1.75 to arrive

The previous wiki notes on using ARM with QEMU didn't cover using qemu-system-arm under libvirt management. This meant that you couldn't easily take advantage of libvirt benefits such as automatic network setup (with DHCP and NAT), the virt-manager GUI tool, guest autostart, or disconnection/reconnection to the console.

I've updated https://fedoraproject.org/wiki/Architectures/ARM/HowToQemu to include some basic notes on setting this up, and provided some files to simplify and speed up the process. Jump in and join Fedora-ARM, the water's nice!

Mock config for ARM building

nospam@example.com (Chris Tyler) — Wed, 24 Feb 2010 09:50:08 -0500

mock is a Fedora package building tool. When invoked to build a specific package from a source RPM (which contains the package source plus a spec file), it creates a chroot environment, populates that environment with a very small set of base packages plus the build requirements specified in the spec file, and then attempts to build the package in that environment. This permits the build environment to be (somewhat) isolated from the host environment, so that a different set of build dependencies (tools, libraries, and headers) can be used for building. It's ideal for proving that the build requirements are correct, and it also permits you to build a large set of packages without installing a lot of build dependencies on the host system. It's also a highly automated and very convenient way to build

I've been experimenting with building for and on the ARM architecture. Fedora 12's mock package does not include a config file for ARM; here is a config file I've cobbled together as a starting point:

config_opts['root'] = 'fedora-12-arm'
config_opts['target_arch'] = 'armv5tel'
# The chroot_setup_cmd is usually 'groupinstall buildsys-build' but that hasn't been defined for ARM yet.
# Instead, the package list is specified here.
config_opts['chroot_setup_cmd'] = 'install bash bzip2 coreutils cpio diffutils fedora-release findutils gawk gcc gcc-c++ grep gzip info make patch redhat-rpm-config
rpm-build sed shadow-utils tar unzip util-linux-ng which bash curl cvs fedora-release gnupg make redhat-rpm-config rpm-build shadow-utils'
config_opts['dist'] = 'fc12' # only useful for --resultdir variable subst

config_opts['yum.conf'] = """
[main]
cachedir=/var/cache/yum
debuglevel=1
reposdir=/dev/null
logfile=/var/log/yum.log
retries=20
obsoletes=1
gpgcheck=0
assumeyes=1

# repos

[fedora]
name=fedora
mirrorlist=http://mirrorlist.fedora-arm.wantstofly.org/?repo=fedora-12&arch=arm
failovermethod=priority

[updates-released]
name=updates
mirrorlist=http://mirrorlist.fedora-arm.wantstofly.org/?repo=updates-released-f12&arch=arm
failovermethod=priority
"""

This uses the existing fedora-arm repositories along with an explicit list of base packages for the mock environment. Ultimately, the buildsys-build package group will be specified in a special-purpose repository, but the explicit package list given here provides a good starting point.

Update: here's a link to this mock config file: http://cdot.senecac.on.ca/arm/fedora-12-arm.cfg

Clarity in Error Dialogs

nospam@example.com (Chris Tyler) — Sun, 21 Feb 2010 15:37:34 -0500

I've met my share of error dialogs through the years. Ones that say "Something bad has happened. Ok?" are annoying but understandable.

However, one in gpk-update-viewer, which I encountered yesterday, is a real head-scratcher:

This dialog sometimes appears when you try to close the gpk-update-viewer window while updating and it reads:

Cannot cancel running task
There are tasks that cannot be cancelled.
[Cancel] [Quit]

Quite apart from the fact that this dialog shouldn't appear at all -- packagekit will continue the update in the background -- the two buttons appear to mean the same thing, both of which are (according to the dialog) impossible.

(bug 567135)

Update: Richard Hughes noted in the comments that this is fixed upstream

Networking at FUDCon

nospam@example.com (Chris Tyler) — Wed, 02 Dec 2009 15:12:30 -0500

What happens when you get 170+ geeks together? You melt the network, of course!

Two network-related suggestions for FUDCon:

(1) Disable IPv6 DNS support in Firefox by going to the pseudo-URL about:config and then changing the value of network.dns.disableIPv6 to true. This will prevent Firefox for waiting for IPv6 timeouts before trying IPv4, reducing page load times for sites such as the Fedora wiki to less than a second instead of a minute or more (we need to figure out why this is happening on networks that don't serve IPv6 DHCP information -- apparently this is an issue on Macs as well, where network.dns.disableIPv6 defaults to true as a workaround. This affects more than just Firefox -- it's an issue with curl as well (but not wget).

(2) Bring an ethernet cable. We will have wired ports available in some of the hackfest rooms on Sunday and Monday to lighten the load on the wireless network, so please plug-in if you're doing high-bandwidth work (video uploading, or rsyncing your laptop Fedora repository). Speaking of local repositories, there is a local private Fedora mirror, http://belmont.senecac.on.ca/fedora/, which the Fedora mirror system will automatically select for you when you're on campus.

Some general FUDCon packing suggestions are on the wiki.