The Musings of Chris Samuel

For those computer history buffs it is sad to learn that the Linux kernels DECnet code is going to be orphaned in 2.6.33, the git commit by Christine Caulfield says:

Due to lack of time, space, motivation, hardware and probably expertise, I have reluctantly decided to orphan the DECnet code in the kernel.

Judging by the deafening silence on the linux-decnet mailing list I suspect it’s either not being used anyway, or the few people that are using it are happy with their older kernels.

To be honest I’m surprised it’s lasted this long, the last time I used DECnet in anger was around 1997 I think..

From Valerie Aurora on POSIX semantics:

It may not be POSIX, but the programmer’s intent is clear – no one ever, ever wrote “creat(); write(); close(); rename();” and hoped they would get an empty file if the system crashed during the next 5 minutes. That’s what truncate() is for.

Finally we have some good news about the Nokia N900, according to Reuters!

HELSINKI, Nov 10 (Reuters) – Nokia (NOK1V.HE) has started deliveries of its new top-of-the-range model N900, a key product for the world’s top phone maker in its battle against rivals iPhone and Blackberry.

Nokia Chief Executive Olli-Pekka Kallasvuo said in a speech the company started deliveries of the phone on Tuesday.

The Nokia press site has not yet been updated, but hopefully soon..

Update: The Nokia Conversations Blog is now covering the shipping, saying:

Today sees the first batch of Nokia N900 handsets boxed up and shipped out on their maiden voyage into wild.

Hooray! Now does this mean that they are being shipped from the factory to the resellers, or are already at the resellers ready to go to customers ?

Update 2: Well it appears, according to this blog post, to be from the factory to resellers..

The shipments of the Nokia N900 have now started. The factories are now working full speed and the devices are on their way to distribution.

So it does look like Amazon won’t have theirs to ship to my friends in the US before I get to LA, so I’ll miss the chance to play with it for a while. Oh well at least they are shipping!

Wow, this is pretty impressive, there is a WIP port of Q3A to the Nokia N900 using the accelerometers to control movement and there are some videos up to see using the TV-out on the phone:

Someone even video’d a multi-player demo at the Maemo summit..

It’s not publicly available (for the moment at least) from what I can tell, a comment on YouTube says:

Currently not (“yet” I’d guess) – but remember that this is just a work in progress / feasability study – this is only a developer version that got distributed over the weekend during the Maemo Summit 2009 in Amsterdam.

Still, looks fun!

Update: the document linked to below has either been removed or moved on the Nokia site, the link has gone 404.

OK, so I spotted that the PDF manual for the Nokia N900 was online and so I grabbed a copy of it to read through. Of course, like all user manuals, it talks about lots of bits and pieces but doesn’t go into the technical details for some decisions, so as a result I’m puzzling over a couple of points. They are:

1. Can you charge the phone whilst it is off ? Might sound like a silly question but the Neo Freerunner has to be on to charge.
2. Is the Offline mode the N900’s version of Flight Mode or Airplane Mode ? The manual says that you can’t make or receive calls, no wifi, etc. But it goes on to say that “Calls may still be possible to the official emergency number programmed into your device”. I’m guessing that means that if you try that it’ll power up the GSM modem for that call, but it’s just a guess. (Page 33)
3. Why can’t the A-GPS service use Wifi ? The manual says that only “a packet data Internet access point can be used.”. (Page 77)
4. Whilst saying that most updates can be installed using the N900 itself the manual also says that “an update using the Nokia Software Updater may sometimes be necessary”. This is Windows only software – any chance of a Linux version, or can something like dfu-util be used instead ? (Page 85)
5. Does the N900 automatic time update use NTP, GPS or the GSM time information some carriers provide (or some combination) ? (Page 97)

If you’ve any ideas or inside knowledge on any of those points I’d love to know!

Catching up on PLOA I noticed a posting from Greg Black bemoaning the lack of ZFS in Linux so I thought I should make a couple of quick points in response to it.

1. The CDDL/GPL thing is just down to the fact that their requirements are incompatible (Sun based the CDDL the MPL), so you can’t mix that code. Just have to live with that.
2. A major issue with ZFS is that there is ongoing patent litigation in the US between Sun and NetApp over it – it’ll be interesting to see what Oracle do when they finally take over Sun (assuming Sun doesn’t expire before the EU regulators comes to a decision on the takeover)
3. ZFS-FUSE isn’t dead! Whilst Ricardo has stopped work another group has taken up the challenge and there is a new home page for it – http://rudd-o.com/new-projects/zfs – complete with Git repository (no more Mercurial, huzzah!).
4. The ZFS-FUSE mailing list is active too, if you want to learn more.

Chris Smart has pointed out an interesting little titbit in Greg K-H’s “Staging tree status for the .32 kernel merge” blog post:

hv (Microsoft Hyper-V) drivers. Over 200 patches make up the massive cleanup effort needed to just get this code into a semi-sane kernel coding style (someone owes me a bit bottle of rum for that work!) Unfortunately the Microsoft developers seem to have disappeared, and no one is answering my emails. If they do not show back up to claim this driver soon, it will be removed in the 2.6.33 release. So sad…

So after all that hope about MS releasing GPL’d code it turns out to be a one off code dump (presumably to get them out of a license violation hole otherwise they’d be showing more interest) with no intention of doing anything further with it..

After a reboot today whilst installing KDE 4.3.1 I noticed the following messages in my kernel (2.6.31-rc8) logs (courtesy of the KDE file watcher that was following /var/log/kern.log):

Sep 6 13:53:10 quad kernel: [ 142.842723] EXT4-fs error (device dm-7): ext4_mb_generate_buddy: EXT4-fs: group 287: 5812 blocks in bitmap, 5418 in gd
Sep 6 13:53:11 quad kernel: [ 143.452041] JBD: Spotted dirty metadata buffer (dev = dm-7, blocknr = 0). There's a risk of filesystem corruption in case of system crash.
Sep 6 13:53:11 quad kernel: [ 143.486915] JBD: Spotted dirty metadata buffer (dev = dm-7, blocknr = 0). There's a risk of filesystem corruption in case of system crash.
Sep 6 13:53:11 quad kernel: [ 143.486942] JBD: Spotted dirty metadata buffer (dev = dm-7, blocknr = 0). There's a risk of filesystem corruption in case of system crash.

That didn’t look too good, so I immediately did a “git pull” and happily found 2.6.31-rc9 was out so built that and then did a dual backup, rsync’ing to my local ZFS-FUSE drive (which takes snapshots so I can go backwards in time) and also an rsnapshot to a USB external disk. Then with trepidation I rebooted and found myself looking at an fsck error on /home due to shared blocks between an image and part of my local clone of Linus’s kernel git tree (d’oh!). Whilst the fsck got the filesystem mountable again it did result in not being able to view the kernel git tree due to missing files so I decided it was far safer to just revert to my latest backup, which worked like a charm (phew!).

Moral of the story – keeping backups is good – keeping lots of backups is even better, especially when running with release candidate kernels!

If you’re a KDE Ubuntu user (Kubuntu) you might not know that the standard readahead package (which attempts to speed up boot by preloading the kernel file cache by efficiently reading them in advance) is tuned for the Gnome version of Ubuntu and so will be trying to read a bunch of libraries that are probably not installed on your system. So it’s unlikely to do much for your average KDE user!

However, if when you boot you go into the Grub boot loader and add the “profile” option to the end of your command line (after “quiet” for instance) then it will profile the files used during the startup and create new files in /etc/readahead so that next time you start you’ll actually be preloading the files that will be used on your system. I’ve found it’s shaved over 2.5 seconds off my boot time as recorded by bootchart.

There is a bug in Launchpad for this, it’s 369506 but it hasn’t had a lot of love.

So it’s just over two weeks since I started with Android on my FreeRunner and it’s time for an update. First of all I’m no longer using the Koolu images, they lack echo suppression support and as soon as I found that Michael Trimarchi’s Panicking port of Android does do echo suppression I switched. The added benefit of changing was that Michaels port has fixed the go-slow feel of the Koolu version and feels responsive and usable in most situations (though the soft keyboard is still a little slow).

Good points:

1. Calls work flawlessly.
2. SMS works flawlessly (and has a nice interface)
3. Contacts can be added as shortcuts on the desktop
4. Wifi works (though WPA2 Enterprise networks need some text file magic)
5. GPS works nicely (I used GPS-status to see how many satellites it can see)
6. Bluetooth works – or at least finds devices when scanning – not gone any further with that
7. Web browser works nicely, even supports Google Gears

Bad points:

1. NO ACCESS TO THE ANDROID MARKET – the Android Market application is not open source (a decision by Google) so you can’t access any applications hosted there. Whilst there are alternative sources they only have a fraction of the applications so this does limit things.
2. The phone seems to stop being able to suspend if you define a APN for GPRS/MMS access. Resetting the APN to the defaults (none) fixes it though.
3. I don’t seem to be able to download MMS/PXT’s – I suspect this is related to the APN issues and I may just not have the right info
4. Accelerometers don’t appear to work – or at least the marble game I had didn’t react to me tilting the phone.
5. Battery life doesn’t seem to be quite as good as Qtopia/Qt-Extended/QtMoko – I have to charge every 24 hours at present. That said the later kernels don’t seem to give me quite as long a lifetime as the 2.6.24 based ones so that may not be Androids fault..

But all in all I’m really quite happy with Android on FreeRunner, it easily outshines my previous favourite of Qtopia/Qt-Extended/QtMoko in terms of overall polish and usefulness as a phone! Thanks to all involved in the porting effort, and especially Michael.