Blackbox
Handhelds.org maintains a slightly customized version of Blackbox optimized for the one button interface that the touch screen provides, it's also patched for XFree86's new RENDER extension. In other words, it supports anti-aliased fonts.
Unfortunately the configure script for this hacked up version of Blackbox isn't the smartest script in the class, so if the instructions look like a kludge it's because they are.
$ cvs -d:pserver:anoncvs@cvs.handhelds.org:/cvs
login
(Logging in to anoncvs@cvs.handhelds.org)
CVS password: anoncvs
$ cvs -d:pserver:anoncvs@cvs.handhelds.org:/cvs cp
apps/blackbox
$ cd apps/blackbox
$ export CC=mipsel-linux-gcc
$ export
CFLAGS="-L/usr/mipsel-linux/X11R6/lib"
$ export CXX=mipsel-linux-g++
$ ./configure --prefix=/usr/mipsel-linux/
$ make LDFLAGS="-L/usr/mipsel-linux/X11R6/lib -lXft
-lXrender -lfreetype"
$ make install
Again, we'll hold off on copying the files to the compact flash at this point.
fscrib
It's somewhat unfortunate that most CE devices don't have any decent means of input, specifically a keyboard. To get around the lack of input devices fscrib turns the entire screen into a Graffiti pad. It takes a bit of getting used to, the character recognition sometimes leaves you wondering exactly what it was thinking, but as an input method it works a lot better than onscreen keyboards.
$ cvs -d:pserver:anoncvs@cvs.handhelds.org:/cvs
login
(Logging in to anoncvs@cvs.handhelds.org)
CVS password: anoncvs
$ cvs -d:pserver:anoncvs@cvs.handhelds.org:/cvs cp
apps/blackbox
$ /usr/mipsel-linux/X11R6/bin/xkmf -a
$ make
$ make install
$ mkdir -p
/usr/mipsel-linux/root/.classifiers
$ cp classifiers/* skin.xpm /usr/mipsel-linux/.classifiers
-a
Putting it All Together
So now we have everything in /usr/mipsel-linux. I'm not going to bore you with the details of how to copy that over to the compact flash card, you can pretty much copy it over directly. You might want to clean up things before you do though: The static libraries and include directories are no longer needed and may be deleted to save space.
Before running the X server you'll have to calibrate the touch screen. The calibration is done simply with by running the command tpcal > /etc/tpcal with the serial console. You only need to do this once since the calibration of an individual unit won't change from one bootup to the next.
Conclusion
So, was it worth the trouble? That all depends, it's certainly not practical by any means. To fill the majority of a compact flash card with the base operating system doesn't leave much room for extra applications or storage. The other downside is that with CE in ROM it'll always boot to CE on power-up. If you're serious about running Linux on the handheld you can purchase an iPaq, load Linux into flash ROM and still have the compact flash left over for an IBM micro-drive. You can even use the PCMCIA sleeve with an 802.11b network card and NFS mount storage as needed. The Casio E105 only has a single compact flash slot for expansion so after booting Linux there's not much potential for expansion.
Still, all things considered, it's still rather impressive and fun to see Linux running on the handheld.
Links
Links to various resources and home to many iPaq related projects.
ftp://Linux-VR.sourceforge.net/pub/linux-vr/
Linux on the MIPS, homepage is somewhat dated.
http://www.agendacomputing.com/
Home of the Agenda VR3 (MIPS based linux handheld)
http://www.netbsd.org/Ports/hpcmips/
NetBSD on the MIPS.
http://Linuxsh.sourceforge.net/
Linux on the Hitachi SuperH.
Development on QT's Palmtop Environment