[959] in linux-scsi channel archive
Re: Adaptec -> NCR
daemon@ATHENA.MIT.EDU (Gerard Roudier)
Sun Nov 17 15:03:01 1996
Date: Sun, 17 Nov 1996 22:00:01 +0000 (GMT)
From: Gerard Roudier <groudier@club-internet.fr>
To: "Leonard N. Zubkoff" <lnz@dandelion.com>
cc: stephen@it.com.au, linux-scsi@vger.rutgers.edu
In-Reply-To: <199611171722.JAA00898@dandelion.com>
On Sun, 17 Nov 1996, Leonard N. Zubkoff wrote:
>
> From: Stephen Darragh <stephen@it.com.au>
> Date: Mon, 18 Nov 1996 00:12:04 +0800 (WST)
>
> I've just installed an NCR53810 based host adapter (ASUS SC200).
> So far I've moved two of five drives from an Adaptec 1542CF (still
> also in the system to support the other three) to the new adapter,
> and I'm waiting on a Buslogic 958 to put the others on plus some
> new drives.
>
> Question: Why doesn't wasn't the system able to read the filesystem
> correctly when the drives went on the NCR? (I had to remake the fs
> and restore - which was a bugger since one of the disks was part
> of a striped array.)
>
> Will I encounter the same problem with the Buslogic
> adapter?
>
> I believe the BT-958 will handle the partitions from the Adaptec 1542 just
> fine.
I am sure that the aha1542 driver of linux, at least until some 2.0.X
revision does not probe correctly "extended BIOS translation" option for
1542CF controllers.
How can the BT-948 guess?
Does it assume that user has set "extentend translation" for disks
capacities >1024x64x32 sectors?
My opinion is the following:
- linux ncr drivers use scsicam_bios_param() (drivers/scsi/scsicam.c).
This function first tries to infer mapping from partition table. If that
fails, it tries to apply SCSI2-CAM (X3T9 / 792D) etc... in order to
assign a disk mapping in tracks, heads, sectors.
- linux buslogic driver does some reverse engeniering of adaptec propriatary
bioses to choose disk mapping.
So, it is possible that users who used old adaptec controllers will
be more fortunate with BusLogic driver.
However, if drives have more than 1024x64x32 sectors they can have
problems too.
Gerard.
