Quoting Brian Rose (saider@gate.net):
...
> I am building for a i386 target. The machine is a PC104 sized system 
> with a 2GB hard drive and a 32MB Disk-On-Chip. My goal is to develop a 
> small NetBSD system that will fit on the DOC without the need for a hard 
> drive. But for now I am booting off of the hard drive. There is no 
> floppy in the system. I installed NetBSD and then to test out my 
> modified kernels, with their built in filesystems, I simply ftp the 
> memdrive kernels into the root of the hard drive, reboot, and select the 
> memdrive kernel from the bootloader. The root partition is only 400MB in 
> size, so there should be no 1024 cylander boundary problems from the 
> bootloader.


<big snip of details>

I've been building BSD on Compact Flash for 18-20 months or so.  I can
get it down to 10MB with crunch gen, though 32 makes for more tools
(perhaps not needed for several embedded tasks).

Thing is you have limited RAM usually.  So you *don't* want to suck
away a bunch with MFS/Ramdisk stuff.  I put *parts* of /var on that,
/dev/ and that's all.  With a 64MB machine running BIND, you want
a little for zone files (all secondary) and I run dhcpd (some data)
and that's about it.  The rest is NAT, firewalling and wireless.

"root is only 400MB" makes me wonder on the definition of "embedded".
If you can't find a working system in 32MB, you're not embedded.