[ale] What format is the "make zdisk" Linux boot disk ?

[Jason Boyles]

On Fri, 31 Oct 1997, Joe Whitaker wrote:

> When using the command: "make zdisk"
> The disk boots just fine.
> What format is it? 

	gzipped ELF with a loading/decompressing boot block prepended.
	
	It's just a raw copy of /usr/src/linux/arch/i386/boot/zImage
written starting at block 0 of the floppy.

> How can I mount it?
> I tried to mount it as msdos, ext2, 
> and some others, but no luck.

	You can't mount it, afaik. Unless you write an fs driver to read a
zImage from a block device and somehow represent it as a file system. :-) 

> How can I copy it to make a backup?

	You could dd it from floppy to a file and then dd the file onto
another floppy, or just dd your extant zImage (usually
/usr/src/linux/arch/i386/boot/zImage) to /dev/fd0H1440 (or /dev/fd0, if
you trust the floppy driver format recognition code) like so:

dd bs=8192 if=/usr/src/linux/arch/i386/boot/zImage of=/dev/fd0H1440

	This brings up another question for me: normally I dd zImages
without using the block size parameter. Why does the author of 
/usr/src/linux/arch/i386/boot/Makefile choose to add the bs=8192
parameter? My bootable kernel floppies work fine, even though I
rarely use make zdisk, and thus no bs flag.

	Perhaps it is a convenient multiple of the floppy block size?


----
Jason Boyles <jason at alltel.net>
"Welcome to The Sanctuary of the Select. If thee come wielding
the sword of faith to dismember children of sin, thou art welcome."