Linux-kernel mailing list archive 1999-32,: Re: > 1 meg bzImage

# Re: > 1 meg bzImage

Robert de Bath (rd103980@home-box.demon.co.uk)
Mon, 9 Aug 1999 08:06:05 +0100 (BST)

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On Sat, 7 Aug 1999, Rick Hohensee wrote:

> Can a 1.3meg bzImage boot off floppy? Or do you mean boot code including
> that in a bzImage itself?
AFAIK the _only_ booter that can't deal with > 1Mb is the one in the floppy
boot sector in the bzImage. So you could just diable the check. Or leave it
in and if the image is > 1Mb replace the boot sector with one that just
outputs a message saying "Use LILO" ... :-)

(Everybody, there's a minor kernel suggestion at the end ... )

> There's something vaguely related to open source issues here, although not
> directly pertinent.. How come floppy drives aren't bigger these days? I
> took apart a 2.88 meg floppy drive the other day. The head positioning
> stuff is rather simple. The 2.88 meg drive was probably built around 1991
> or 2. A 20 meg floppy drive would be a good open hardware project. 20 meg
> is a lot of linux/GNU/unix. Most of what I use fits in 12 meg.

The problem is that floppy drives are simple. The head positioning for
720k, 1440k and 2880k is identical, they are all 80 tracks 135tpi.
The capacity is directly linked to the sectors per track (9,18,36).
The problem comes if you try to increase the number of tracks, the
variation in the position of the track on the plastic (floppy) medium
is too large for a fixed head to stay on track. You either have to make
the medium stiffer, a JAZZ or Syquest drive, or make he head positioning
active by laying down physical lines on the disk for the head to follow,
LS-120 and Zip drives use this.

One thing that's a little annoying tho is that these drives don't fit on
a floppy interface - ie: a faked one (eg: like ST-506 vs IDE) - I suppose
doing an IDE like CHS mapping on a floppy wouldn't be compatible enough
as all floppies have 1 or 2 heads.

Please could one (or four) of the floppy minors be mapped onto the
first IDE LS-120 drive or sda1-4 of a Zip drive for multi-system boot
'super-'floppies because otherwise it's _impossible_ to predict which
device the floppy drive will be so we can't mount root!

    --
    Rob.                          (Robert de Bath <http://poboxes.com/rdebath>)
                        <rdebath @ poboxes.com> <http://www.cix.co.uk/~mayday>

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