Re: bootxx needs to fit within 0th track of MBR partition?

[Martin Husemann <martin%duskware.de@localhost>]

On Fri, Aug 25, 2023 at 05:43:16PM +0900, Rin Okuyama wrote:
> If we can require at least 3.5inch 2HD disks for amd64,
> BOOTXX_SECTORS can be bumped to 18, and build passes.

I would guess the only real use of boot floppies for x86 machines
nowadays is via emulators. For example py-anita prefers floppy images
for amd64 (but works fine with other types of images).

We may consider dropping them all. Pretty sure there are not many floppy
drives and floppies in working condition around (or in use). I have
a machine with a 3.5 inch drive (486) but the floppy drive is either
broken or all media I tried are bad. I'm currently booting it from a
SCSI ZIP drive.

> But, I've never found the original resource which says
> "second stage loaders in MBR partitions ought/need to
> fit within 0th track".

I think this used to be a limitation of the boot code inside the MBR.
The BIOS really only loads the the MBR, everything else is done by the
code in there and other code it loads and chains to.

Martin