OK - there was a BSD troll thread a few days ago. The guy didn't understand that modern Linux is really built from set of packages (plus an installer). So I decided to see how low I could go - how minimal a Fedora install I could create.
I started with the F9-i386 installer, and when it got the packages I selected customize now.
I deselected Gnome & all Apps and all the extra sysadm utilities. The installer claimed is was installing 253 package, but when I rebooted and did a yum list | I found 305 packages actually installed and about 600MB in use. Oh yeah - I selected busybox for installation too.
I typed a shell command that tried to remove each package - but I prevented removal of critical bits; kernel, yum, busybox, grub and the bits these depend on. I ended up with only 78 packages left. I rebooted to check I hadn't gone too far.
Next I make links for busybox and editted a new strtup script & inittab for busybox syntax. It took a few tries but I got the system to reboot using busybox startup.
I removed the initscript, coreutil. Then the big enchilada - I tried to do a yum erase on one of the low level dependency libs for yum. It *should* have removed all but 4 of the remaining packages - but as you would expect yum failed once the rpmlibs were removed. It seemed to leave abt 4 or 5 packages incompletely removed.
Anyway after a little manual janitorial work I had it down to kernel+busybox.
(note - busybox is statically linked so I dumped glibc).. Busybox is a great little embedded tool - a functional version of 100+ utilities. I got the network up w dhcp, the busybox shell was OK, getty on the other console ttys - the entire userland was busybox - really pretty functional.
The minimalFedora system weighed in at 67MB. 58MB was in /lib/modules. I could easily pare that down to a few MB, remove unused drivers with a little work. Another 6.5MB was in /boot and 1.7MB in busybox. Aside from the homemade inittab and rcS (init script) it was all from the Fedora distro,
I've done the opposite (built an embedded Linux up from nothing) dozens of times, but I've never stripped a distro down so far. It is possible and not even very hard even.
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A few odd things. I de-selected Gnome & X, but there were still half a dozen gnome- and xorg- packages installed. Yum has a *lot* of dependencies ~55-60 packages. Actually busybox has an "rpm" feature but it doesn't support the "-e erase" option ... too bad would have been easier.
Too bad the package selector in the installer doesn't have a list feature like pirut. I believe you could just install kernel, grub, busybox, then reboot the installer DVD in rescue mode and make the busybox links & the inittab & initscript.