Debian on the Sharp Zaurus/SL-5xxx

The Zaurus is a Linux-based PDA from Sharp. More information about the Zaurus can be found in many places.

The Debian Zaurus project aims to create a full-featured, plug-and-play Debian environment for the Zaurus, with all the trimmings, including package management with dpkg and apt. A small demo is available.

Roadmap

Debian's ARM port is already quite usable, and provides a huge wealth of binary packages that can be used on the Zaurus. Most of the components necessary for building and using PDA applications are already ported and working.

The Debian Zaurus project will take the form of some additional Debian ARM packages, and some Zaurus-specific tools. So far, I can see that at least the following software components will be required:

A Zaurus-tailored Kernel
Packages for kernel patches providing hardware support for the Zaurus
A ROM image
Tools to build a kernel and a minimal root filesystem suitable for flashing into the Zaurus.
User programs
Packages for software to provide PDA functionality, and modifications to existing software to better suit a PDA environment.

Some other things which might be useful include:

The base system shall fit within the internal storage provided on the SL-5500 (16MB flash ROM + 64MB persistent RAM storage + main memory), or hopefully the SL-5000D (16MB flash ROM + 32MB storage/RAM), however, I hope to work out a mechanism for gracefully expanding the system onto CF and/or SD cards, to allow for more installed software, while allowing those cards to be inserted and removed without losing basic system functionality.

Due to the specialized requirements of a PDA environment (including limited storage and power resources) the base system will probably omit certain components that are otherwise part of a base Debian installation, such as fdutils, sysklogd, most documentation, etc. At the same time, if possible, the base system may include a set of applications to provide basic PDA functionality and a graphical environment. These modifications to the base system will be automated as part of the image creation process, so that the remainder of the system stays in sync with the rest of Debian/ARM.

Status

2003/12/21 15:23 PDT
Everything here was restored from a backup. Summary: I haven't done anything lately. Other things are happening on debian-handheld@lists.debian.org.
2002/12/07 12:06 EDT
I've been spreading myself too thin, and have not had time to work on this project. My Zaurus has been in its cradle continuously for the past couple of months. There has been a lot of interest in this project, and I am interested in finding volunteers to continue the work until I can come back to it. Contact me.
2002/08/10 23:35 EDT
I've updated the image to current 'testing'. Among other goodies, this means that ifup now correctly interfaces with udhcpc. I also trimmed things down a bit further so that there is now over 1M free. All of the same packages are installed, but some bits which are not generally useful on the Zaurus have been stripped out.
2002/08/10 22:42 EDT
After teaching mkfs.jffs2 about hardlinks, and trimming down more installed packages, I now have a jffs2 image which includes X, matchbox and xvt. Since the Sharp kernel does not include jffs2 support, this means that you must use an OpenZaurus kernel with this image. See the ROM image page for more information.
2002/08/04 00:19 EDT
I had to remove X to do it, but I've created a jffs2 initrd which works with the OpenZaurus kernel. This means no more read-only root filesystem hackery, but it also means less software. I can regain some of the space once mkfs.jffs2 can properly handle hard links (or I translate them to symlinks), at which point I think the tradeoff will be worth the writability. I should have something to upload in this area soon.
2002/08/03 19:43 EDT
I'm struggling with the size of the initrd. While it is fine for cramfs, I want to be able to use jffs2 (for writability), but jffs2 is significantly less space-efficient.
2002/07/27 13:21 EDT
Another initrd update. I've reverted to XFree86 4.1.0, since it seems more stable, and includes a simple hack to rotate the screen if the Y dimension is greater than the X dimension. Start the X server with "-screen 240x320" and everything should be rotated correctly. It also includes rxvt, the first actual GUI application to be included, and a 'zstartx' script.
2002/07/26 21:18 EDT
Another initrd update. It acts more or less like the previous one, but uses pivot_root instead of a bunch of messy bind mounts. Hopefully, this read-only root business is only temporary anyway, but this makes it less painful in the meantime. In case of problems, this image drops you to a shell immediately so that you can examine the system even if it is partially broken. Exit this shell for normal startup. Note that the X server display is still rotated 90 degrees, since xrandr seems to segfault.
2002/07/24 01:12 EDT
A new initrd is available. This version now includes an X server (Xfbdev) and window manager (matchbox)! Space is getting tight, and there are still no actual applications. Of course, there is room on the writable flash, but it would be best if everything necessary for basic work were included in the base image. The X libraries are huge, though. I have some trimming and squeezing to do.
2002/07/23 23:57 EDT
After many cross-compiles and many debugging sessions, I've fixed a couple of bugs which caused the bus errors and incorrect touchscreen behaviour. I should be able to prepare an X-enabled initrd RSN.
2002/07/21 23:14 EDT
I've put together a preliminary source package for building Xfbdev from partial XFree86 sources. Installed-Size: 745 should fit nicely in the initrd. Next, I'll need to do some tinkering to determine the minimum amount of other X stuff that will be necessary in order to do useful things, and try to make that fit. I've written a replacement for a small daemon that I found which converts Zaurus touchscreen events into iPAQ touchscreen events (which XFree86 understands). I think it was probably free, but the author seems to have vanished, and the source code is nowhere to be found.
2002/07/21 12:31 EDT
The next big hurdle is XFree86. After much tinkering, I've managed to cross-compile a working Xfbdev from XFree86 4.2.0, weighing in at about 800kb. It starts, works, runs xeyes and other important things. I'm trying to use the Xrandr extension to rotate the screen 90 degrees, but it gives bus errors when changing the rotation. It also gives a bus error on shutdown, and doesn't bring the display back to text mode, though. Some of this may be fixed in XFree86 CVS.
2002/07/19 10:47 EDT
I found out what was causing the initrd to be overwritten by an older copy, and have fixed it. The md5sum for the current initrd is 179fd823882ab63520fe96ebca2ba73c.
2002/07/18 16:23 EDT
There have been some serious problems with these pages, apparently. The initrd had not been updated when I said that it was, and the email address that Emacs placed at the bottom of each page is wrong. I have corrected both of these errors. If you have not been able to reach me via email, or if you could not get the initrd to work properly, please try again.
2002/07/17 23:32 EDT
I've updated the initrd again, see the ROM image page. Nothing major, just added some device nodes that should have been there by default, and some zaurus-base updates that I can't remember.
2002/07/14 22:11 EDT
The Embedded Debian project came to my rescue by providing a plug-and-play ARM cross-development environment which worked out of the box, on the first try. Now work can continue on building a free, standard kernel.
2002/07/14 19:12 EDT
Started looking into rebuilding the kernel, as a starting point for having an entirely free kernel, and also for updating to a more recent one. Am having a hell of a time getting just the right cross-compiling gcc, because the kernel needs to be built with -msoft-float.
2002/07/14 12:02 EDT
I've written a replacement for Sharp's /sbin/oncheck program, which allows me to test for the hardware reset condition. This means that the latest image will only mkfs the writable area if you press the hard reset button. I've also reduced its size by another 500k or so (compressed), making more room for the additional infrastructure and applications that we will want in the base image.
2002/07/14 00:25 EDT
I'm putting up a new test initrd. This one will basically boot, and you can login as root/root. The biggest 'gotcha' currently is that since the /rw filesystem needs to be mounted very early, it is not fsck'd by normal means, and so is currently not fsck'd at all. This is not a big deal, since currently it is mkfs'd every boot. This should be fixed soon.
2002/07/13 23:09 EDT
Making good progress with the ROM initrd. I am putting together packages to configure everything automatically, handling the read-only root filesystem weirdness. The current image, which I have only halfheartedly tried to strip down, occupies less than 2.5M of the writable area. Most of this is the dpkg database, which we can't do much about (yet). Package installation seems to work, even replacing those which are installed on the initrd. The symlink magic is working out well. Running apt-get update on this image eats up a whopping additional 10M or so, but installing packages via APT does work. My current challenge is to get the CF card working under Debian, so that I can flash new stuff without having to revert to the stock Sharp image.
2002/07/13 15:44 EDT
I've been tinkering with X, trying to get a useful GUI together. The stock X server segfaults, and I'm having difficulty getting the usual debugging tools to work properly. This may be due to the fact that I'm stuck with Sharp's 2.4.6 kernel for now. Any X or ARM experts would be more than welcome to give me a hand with this part.
2002/07/08 23:23 EDT
I've put up a test initrd. This is VERY rough stuff, only for the adventurous who don't need to do any real work on their Zaurus for a while.
2002/07/06 21:52 EDT
I took a shot at building Opie from CVS sources. Yuck. It wants to install itself under /usr during the build process, and is otherwise ill-behaved. Time to take a second look at GPE.
2002/07/06 18:42 EDT
Starting to worry about kernel issues. It looks like I won't be able to use this SD card without Sharp's closed-source driver, which will make it much less convenient to experiment with new kernels. MMC is rumoured to work, so I may need to pick up an MMC card. This project is getting expensive.
2002/07/06
I just was able to perform my first installation of a Debian package natively on the Zaurus, not within a chroot. Most everything is set up by hand at this point, and I am still using the stock Sharp kernel, but this is a step in the right direction.
2002/07/05
Time has been short recently, but I have started working on the ROM image again. I have successfully booted a read-only Debian image from Zaurus flash using the stock Sharp kernel. There will be some trial and error before I have something usable in this department. Good news: the stripped-down Debian image I booted is actually smaller than the stock image from Sharp: 31M vs. 33M uncompressed, 12M vs. 14M compressed. This is without qt-embedded or any applications, however. With the Sharp image, and perhaps with future Debian images, variable stuff will be stored as tarballs, and unpacked into the writable storage area after a hard reset, rather than stored directly in the cramfs initrd. This may save some space, and allow us to add some useful stuff and be not much larger than Sharp's.
2002/06/21
I have had some trouble getting the Zaurus to flash a new ROM image without using their update utility (which would not allow me to back out). It seems that the SL-5500 consumer edition may be different from the SL-5000D developer edition in this respect. The OpenZaurus folks have presumably figured this out, since they support both models. I need to figure out how they do their testing on the 5500.
2002/06/20
I have purchased a second CF card, which should enable me to safely test flash new ROM images into the Zaurus.
2002/06/16
Response has been tremendous. I am currently trying to determine how I can safely test flashing a new kernel and initrd into the Zaurus ROM. So far, it looks like this will require the purchase of a second CF card, so that I have something to back out to if (when) it doesn't come up correctly.
2002/06/15
Just got started. We need developers, testers and input on how to proceed. I have built and used potato and woody chroots on a Zaurus, and am investigating the organization of the kernel and flash ROM used in the stock Zaurus software.

Resources

Sharp's developer program
Technical documentation, how-to manuals, Sharp source code
Zaurus ROM image layout
Details the format of the Zaurus ROMIMAGE file. It looks like we probably will not want to use this method, but instead upgrade the kernel and initrd separately. This method is both easier and safer than overwriting the entire ROM image. This allowed me to extract Sharp's kernel from the SL-5500 image, though.
ROM Upgrade instructions
Describes the procedure for installing a new image in the Zaurus' flash ROM
ZaurusZone
Zaurus user and developer community website

Related projects

Thanks

Flint Electronics
for donating a 128MB SD card
Matt Zimmerman
Last modified: Sun Dec 21 15:24:51 PST 2003