freebsd-dev/sys/i386/boot/kzipboot/README
Poul-Henning Kamp 7970b29866 The magic code to uncompress a kernel.
Reviewed by:	phk
Obtained from:	Linux via 386BSD.
1995-04-15 08:23:55 +00:00

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/* Beware: mostly obsolete info */
This is the first (alpha) release of kernel packer/unpacker
for FreeBSD. It is based on xBoot from Linux, but
hardly rewritten.
It assumes that:
1) The kernel should be loaded at 0x100000 phys address.
2) The CS selector is equal to 8, which is OK for all
current secondary boot programs.
Run "make install" to install it. It will place
"kzip" shell script into /usr/sbin, and several files
into /usr/libexec/kzip directory.
Then try to zip your kernel, for example:
% kzip /kernel
System size is 462848
Compressed size 247027
It will create file /kernel.kz:
% ls -l /kernel /kernel.kz
-rwxr-xr-x 1 root 497297 Oct 8 12:41 /386bsd
-rwxrwxr-x 1 root 262144 Oct 8 13:37 /386bsd.kz
Then rename /kernel.kz to /kernel and reboot.
% mv /kernel /o3kernel
% mv /kernel.kz /kernel
% sync
% reboot
During booting, you will see the message:
Uncompressing kernel...done
Booting the kernel
The packed kernel should load and run.
The main problem with packed kernel is the lack of symbol table,
so all commands that require it, will not run.
Among them: ps, savecore, *stat, etc.
Packed kernels are good for install and fixit floppies.
Serge Vakulenko, <vak@zebub.msk.su>
Opdated for FreeBSD 2.1 by Gary Jennejohn 12FEB95