Boot sector
Albert Cahalan (albert@ccs.neu.edu)
Wed, 8 May 1996 17:46:29 -0400 (EDT)
> From: Hans Lermen <lermen@elserv.ffm.fgan.de>
> On Sat, 4 May 1996 jerijian@seas.ucla.edu wrote:
>
>> BTW, doesn anyone know if I can cat a kernel image
>> (Linux 1.3.98) to a 3.5" double-density (720k) floppy yet,
>> or must I be forced to use LILO?
>
> 720k floppies don't work with recent kernels because number of
> setup-sectors (9) have become too big _and_ setup.S is read by
> only _one_ INT13 call.
>
> Here is the related comment in bootsect.S:
> mov al,setup_sects ! (assume all on head 0, track 0)
> =============================
>
> There are only 9 sectors in one track, and we have 1 sector for the
> bootsector, so setup.S crosses the track boundary. To fix this is
> a _big_ problem, because we have no space left in the bootsector.
> And to migrate to setup.S (as we do for bzImages) will not work,
> _because_ we haven't yet loaded setup.S :-(
> Here a list of 'valid' make targets for bzImage:
>
> - make bzImage
> - make bzlilo
> - make bzdisk (this makes the raw floppy)
Let's schedule an incompatible change for 2.1.xx.
The boot sector and the next 3 are code only,
followed by a sector to hold a list of sizes and
checksums for the remaining parts of the image.
These parts could be extra real-mode code, protected
mode initialization code, an initial ram disk, predefined
"command line" parameters, an icon of a greased armadillo,
or whatever.