On Sat, 12 Feb 2000, Jeff Garzik wrote:
Sure you can, as long as the right boot code is attached. The final stage of the kernel build looks something like
make vmlinux make bootcode gzip -9 vmlinux cat bootcode vmlinux.gz > zImage
what a zimage is (in short): 1) 512 bytes of floppy boot block 2) 2048 bytes of secondary boot block. 3) linux kernel startup, with an uncompressed header and a compressed image. The uncompressed header does the gunzip. Since we use openbios gunzip, one of these two gunzips is useless and should be removed. For linuxbios we opt to remove the linux kernel gunzip -- it's dead code after boot, so why put it in? saves a few bytes.
startup: If you're on floppy, the first 512 bytes are read, which reads the second 2048 bytes, which reads the kernel. The start of the kernel is some setup and the 'unzipper'.
If you're on hard drive the standard booters skip the first 512 bytes and go for the secondary bootstrap.
When we build a kernel for bios, we just compress vmlinux itself, minus all the unzippers. I'm going to put this tree on the web page tomorrow.
Sorry if this is too short, isdn is screwing me up again.
ron
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