Re: Small patch to fix an "experimental" onlook

Hans Lermen (lermen@elserv.ffm.fgan.de)
Tue, 7 May 1996 11:58:08 +0200 (MET DST)


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.
( there are BIOSes which support multitrack read, but not all do it
especially those on machines with 720K drives )
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 :-(

... I'll have a look how to fix this.

However 1440-floppy _can_ boot, even with bzImages.
Here a list of 'valid' make targets for bzImage:

- make bzImage
- make bzlilo
- make bzdisk (this makes the raw floppy)

> --- linux/arch/i386/boot/Makefile.orig Sat Apr 20 20:05:13 1996
> +++ linux/arch/i386/boot/Makefile Sat Apr 20 20:05:48 1996
> @@ -90,6 +90,7 @@
>
> clean:
> rm -f bootsect setup
> + rm -f bbootsect
> rm -f zImage tools/build compressed/vmlinux.out
> rm -f bzImage tools/bbuild compressed/bvmlinux.out
> @$(MAKE) -C compressed clean
>

Yup, this patch is correct, though bbootsect currently never changes
under different configurations.

Hans
<lermen@elserv.ffm.fgan.de>