RE: linux + win95: linux boot partition/
The 1024 problem is a very "real" one.
On old BIOSes the 1024 cylinder corresponded to 528 MB.
Newer BIOSes do translation (they pretend the drive has more
heads than it actually does so they can pretend that it
has fewer cylinders than it actually does) and the 1024
cylinder corresponds to about 8 GB. Some BIOSes allow
you to choose whether translation should be done with
settings like "Large" or "LBA" for other BIOSes
translation is on by default.
Only LILO uses the BIOS so only LILO needs to know what
(translated) disk geometry the BIOS is using. (Well fdisk
needs to know the translated geometry when creating new
partitions if you want to maintain compatibility with other
OSes.) LILO gets the disk geometry from the kernel. For
some systems the kernel doesn't default to the same geometry
that the BIOS uses. You can fix this by 1) passing the BIOS
geometry to the kernel as a boot option, 2) telling LILO
the BIOS geometry through LILO config options, 3)using LILO's
"linear" option which causes LILO to record linear sector
numbers in the map file instead of cylinder/head/sector
locations. I prefer option 1) because fdisk will also use the
"correct" geometry. Option 3) just postpones conversion of sector
numbers to C/H/S locations until boot time (when LILO can get
the BIOS geometry directly from the BIOS). It doesn't solve
the 1024 cylinder problem (which is a 528 MB or an 8 GB
problem depending on your BIOS).
I agree that there are problems with the documentation. Too much
of it implies that the 1024 cylinder problem = 528 MB problem.
Note 1: The DOS program dparam.com (that comes as part of the LILO
distribution) can be used to determine the translated BIOS geometry.
Note 2: Some very new BIOSes support extended 32 bit C/H/S addressing
(up to 2 TB drives) through new BIOS routines. I don't think LILO
supports these new BIOS routines yet.
Tony Richardson
-----Original Message-----
From: Hamish Moffatt [SMTP:hamish@debian.org]
Sent: Tuesday, July 14, 1998 9:37 PM
To: p.meidl; debian-user
Subject: Re: linux + win95: linux boot partition/
On Tue, Jul 14, 1998 at 06:42:19PM +0000, Patrick Meidl wrote:
> after reading the relevant FAQs, HowTOs, installation instructions etc.
> I recognized that all bootable partitions must start before the 1024th
> cylinder (I would like to use LILO), so I thought the best solution
> might be to have these partitions:
With LBA this appears to be incorrect. I have previously had systems
booting Linux from the last 500mb of a 1.6gb drive; the 1024 limit
only takes you to 528mb or so. I boot NT 2gb into a 6gb drive; no
problem.
I have never encountered any 1024 cylinder problem with Linux. I wish
the documentation would not keep spreading these ideas.
Hamish
--
Hamish Moffatt, hamish@debian.org, hamish@rising.com.au,
hmoffatt@mail.com
Latest Debian packages at ftp://ftp.rising.com.au/pub/hamish.
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