Subject: big IDE disks (and DOS stuff - ugh!)
To: None <>
From: Gordon W. Ross <>
List: port-i386
Date: 12/30/1994 11:15:16
> Date: Fri, 30 Dec 1994 20:58:57 +1100
> From: Matthew Barry <>

[ I suggested telling pfdisk to change only "cyls" ... ]

> I tried this, but NetBSD correctly detects that the disk is 2100c 16h
> and 63s. During disk partitioning the sysmts calls fail. I get quite a
> lot of errors from the process and the DOS BIOS record is wiped out.

Sorry, you'll have to ask someone on port-i386 why NetBSD does not
agree with the BIOS about geometry.  [ Anyone care to comment? ]

> I got your latest version and compiled it for unix (SYS=i386) would
> not work. It wrote a boot record, which NetBSD liked. However the DOS
> record was not over-written and when the system booted it did not see
> the NetBSD version.

Note that pfdisk only fiddles with the master boot record (MBR),
never the secondary boot records as is done by DOS fdisk.  This
means pfdisk can not completely create all types of DOS partitions.
(I wrote it when DOS 3.? was the latest thing 8-)  However, if you
make you DOS partition with ID=4 or ID=6 then DOS can deal with it.
The DOS format command will initialize the secondary boot sector.

> I think the problem is that I have some form of enhanced IDE
> controller. This [I] surmise, rather than [know], as I do not need
> any drivers to use the full disk under DOS or windows. Of course such
> drivers may be part of the the standard installation for all I know.
> I certainly did not receive any extra software with my disk.

Perhaps these modern machines have a smarter BIOS than the old junk
I have experience with.  [ anyone know about modern IDE stuff? ]

> Thank you for your assistance. Any further suggestions would be
> greatly appreciated.

I'm not sure I helped.  Hopefully someone else will do better.