First of all... Hi! I've subscribed this mailing list for a few months and I've been around at #emdebian (irc.debian.org) for a while, but I haven't posted yet to this mailing list so here goes a small introduction about myself.
I'm a portuguese student at Universidade de Aveiro (Portugal) and I'm on my last year (I hope) studying Electronics and Telecomunications Engineering. My final project generally tagged Linux Embedded, consists in putting a linux distro running on a pc-like machine (although other options can be considered) with no hardrive, but a compact flash card instead (using an IDE interface). This is intended for industrial enviroments and to be connected to an automaton monitoring and/or controlling some industrial process. I've been a linux user for about 6 years, and a Debian user for about 2 or 3 years, so I wanted to use Debian in my project since the beginning I've been successfully using andersee's uwoody (for those who are new here... basically uwoody is woody compiled with uclibc instead of libc) for a few weeks now. I made two installations with deboostrap (and apt-get after that to add some more packages), one of uwoody (uclibc) and another of "normal" woody (libc), both with the same packages (as far has that was possible), the first was about 128MB large (disk space), the second about 208MB (this included XFree86 and many libs) The uwoody's 128MB compressed with cramfs, squashfs or jffs2 becomes about 60MB. I needed a few packages in debian that weren't in uwoody (and some of those were only in testing/unstable). So I made another installation of a buildroot for uwoody and I successfully rebuilt about 30 packages from debian sources (some from stable and some from testing/unstable). Most of them just by typing dpkg-buildpackage (to be honest I used -d in one or another, but it successfully built anyway). This packages include gtk2.0 glib2 and some other libs required to compile those. The major problem about flash disks is the number of writes you can do on it. So running a rw system on a flash disk won't make it last for too long. I'm currently running an uwoody system on a rw ext2 in a compact flash card (with IDE interface) but I made a few hacks to minimize the number of writes to the disk (btw, thanks to andersee for the help and suggestions and for providing uwoody). The "hacks" I've done to minimize writes were: - use devfs for /dev - use tmpfs for /tmp - on boot create some /var dirs in /tmp and link to it, such has /var/log /var/spool /var/tmp and /var/run; of course that if you need to keep the logs this can't be done just like this, so what I will probably do is to keep this structure but on shutdown and/or every N minutes/hours write the logs to the disk This list is still far from complete, but I've managed to get to a point that after boot no more writes are made to the disk (although the system is kind of idle, logged in X with an application running which doesn't write to disk). On boot I get around 100-150 writes to the disk, I haven't concerned much about this because I don't expect the system to be (re)booted very often. Some might question themselves about "How many writes can I do to a flash disk?", well it depends on the manufacturer, some have internal wear levelling mechanism like sandisk (there's a sandisk paper about this but I haven't the link here now). There is a nice discussion about this in some other debian mailing list, look at debian weekly news and search for a topic such as "debian on usb flash" or something similar. Some of you said that the base system installed by the debian installer was too big, well... try to install the base system using deboostrap. I've installed uwoody this way. You can find more details about installing debian using deboostrap on the debian installation manual. There are already some distributions that run from usb flash keys, many are knoppix customizations (you can find a list of these on knoppix site)
