Subject: Follow up: booting from beyond cylinder 1023.
To: None <current-users@NetBSD.ORG, netbsd-help@NetBSD.ORG,>
From: Baw <email@example.com>
Date: 11/22/1997 02:14:44
Thanks to all who replied to my call for help to "boot a partition
beyond cylinder 1023." It remains impossible to literally boot a partition
beyond cyliner 1023, but with suggestions/hints from various replies, I
managed to install MSDOS, Linux, and NetBSD without having to break them
up into smaller root partitions and larger user partitions. Below is a
synopsis of what I did, and notes on quirks and minor problems
(background info: machine is a Pentium/PCI with IDE harddisk, AMI BIOS)
1. Turned on LBA (Logical Block Addressing)/Address Translation in BIOS.
2. Remapped my disk with a cyl/head/sector geometry of 968/128/63
instead of the true phyiscal geometry of 7752/16/63.
Now the whole disk is BIOS-mapped to within 1024 cylinders.
3. Used PFDISK that runs off an MSDOS bootdisk to partition the drive:
Partition 1 MSDOS
Partition 2 Linux Swap
Partition 3 Linux native
Partition 4 386/BSD
(The 386/BSD definitely lies beyond the 1024th physical partition.)
4. Used "fdisk"s that come with their respective operating systems
to reinitialize their respective partitions. MSDOS seems
particularly peeky and insisted on starting from
cylinder 0, head 1, sector 1. Linux made no fuss on the
partitions made by PFDISK and installed LILO/Linux without a
hitch. I had a little problem getting NetBSD's installation
tool to recognize the remapped 968/128/63 geometry. "sysinst"
somehow figured out the 7752 cylinders that existed and
operated as if the geometry is 7752/128/63 (not 7752/16/63),
even with the "-b 968/128/63" option specified on command
line. (My MBR got wiped out once by sysinst, I believe, as
it confused over the geometry. Maybe I've done something
wrong while using sysinst; anyway, I didn't bother to
reproduce the glitch.) But the "install" program worked fine
after I told it the 968/128/63 geometry, and everything else
went well thereafter (without bothering with sysinst).
5. Installed OS-BS as my boot selector.
Thanks again to all who helped.