LILO now works on lage disks beyond 1024 sylinder limit.

[mikebw at colossus.bilow.com (Mike Bilow)]

Oops, I didn't know this was not generally known.  Nor is it correct...

The 1024-cylinder limit was not imposed by Lilo, but by the ROM BIOS which
Lilo (or anything else) must use to load the beginnings of the operating
system.  For at least several years, Lilo has had support for "logical
block addressing (LBA)" which modern BIOS releases use to support large
disks.  Unfortunately, the Lilo docs have lagged a little behind the
software, and there has been a general misunderstanding of how this works.

In particular, Lilo has long supported booting from a large disk with more
than 1024 cylinders by using the "linear" keyword in /etc/lilo.conf, which
enables (24-bit) LBA.  The Lilo docs imply that this is only useful with
SCSI controllers, but this is because the docs were written when no disks
other than SCSI disks were large enough to worry about.  In fact, the
"linear" keyword will work with any combination of machine BIOS and
controller, SCSI or IDE, which understands (24-bit) LBA.

What is new in the most recent release of Lilo (as of 21.4.0) is support
for 32-bit LBA using the new "lba32" keyword.  The difference is that
24-bit LBA can only access drives up to 8.4 GB, while 32-bit LBA can
access drives up to 2048 GB (2 TB).  Prusumably this will hold us for the
next few generations of disk storage.

There is no harm is using the "lba32" keyword on a disk smaller than 8.4
GB, as long as there is BIOS support for 32-bit LBA.  However, since there
is no guarantee that the mapping will be the same, it would be necessary
to rerun "lilo" whenever any changes are made to /etc/lilo.conf.  Also,
since there is no reliable way to tell if a particular system has 32-bit
support (or even 24-bit support) except by testing, it is wise to have a
boot floppy on hand until you find out.

The new Lilo also adds support for new-style (v0.90) software RAID.  We
beta-tested the Lilo upgrade using a 30 GB + 30 GB RAID-1 array, which
requires both the RAID support and the 32-bit LBA support, and it worked
perfectly.  In fact, DEBIAN.BILOW.COM is actually running Debian "potato"
using a custom kernel and the new Lilo on this array.

-- Mike


On 2000-04-28 at 16:38 -0400, Jerry Feldman wrote:

> I caught this on another listserv. Here is the URL from Freshmeat:
> http://www.freshmeat.net/news/2000/04/26/956756732.html


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