Why the 137gb aka 147 dec gb limit (not normal 28lba prob)?

BIOS Questions that don't belong in the other forums. Read them!
Post Reply
Nil Einne
New visitors - please read the rules.
Posts: 1
Joined: Mon Jan 29, 2007 9:52 pm

I've read all up about the 28 LBA problem but I'm still not sure why some boards have a 137 gb aka 147 decimal gb limit. This is obviously past the 128 gb aka 137 decimical gb 28LBA limit.

For example I have a
Program: eSupport.com BIOS Agent Version 3.61
BIOS Date: 05/03/02
BIOS Type: Award Modular BIOS v6.00PG
BIOS ID: 05/03/2002-8363-686B-6A6LMFGAC
OEM Sign-On: Release date:2002/05/03 Ver:2.60
Chipset: VIA 82C305 rev 3
Superio: VIA 686 rev 64 found at port 7h
with this problem. It reports the drive capacity in bios as 136gb in bios with LBA and CHS mode (large mode reports 128gb). The drive is a 160 decimal gb one. This doesn't appear to be a confused bios using decimal gb i.e. saying 137gb when it means 128gb as if I limit the drive to 128gb with the Hitachi Feature tool it correctly reports it as 128gb not 137gb in LBA and CHS mode. So it appears this bios has a 137gb limit but I don't know why. It's a 686B so it supports 48LBA in theory.

I think other people have had the same problem altho it's difficult to know whether they're talking about decimal or binary based gb sometimes.

Cheers

P.S. Yes I know I can partition the disk so the boot partition doesn't cross the limit and Windows XP SP2 should have no problem using the other partition. Just wondering why the problem exists.
Denniss
BIOS Guru
Posts: 3153
Joined: Thu Mar 21, 2002 8:16 pm
Location: Near Hannover (CEBIT) Germany
Contact:

28Bit LBA limits at 128GiB (Gibibyte, multiple of 1024, that's what computers are counting with) or 137GB (Gigabyte, multiple of 1000, that's what HDD manufacturers are counting with).

Perfectly normal behaviour displaying either 128 or 137GiB/GB. Boards with VIA 686B need proper Bios support for 48Bit LBA, without this native supports ends at 128/137.

With a totally revamped/re-engineered Bios you may even upgrade 486 mainboards to have 48Bit LBA.
edwin
The Hardware Archivist
Posts: 6286
Joined: Wed Mar 20, 2002 7:11 pm
Location: Netherlands
Contact:

That is a Fastfame 8VTAE board BTW.
edwin/evasive

Do not assume anything

System error, strike any user to continue...
Post Reply