Re: aic7xxx and tapse (Was Re: How to force a kernel panic ?)

Richard B. Johnson (root@analogic.com)
Tue, 14 Jan 1997 13:52:00 -0500 (EST)


On 14 Jan 1997, John Henders wrote:

> In <Pine.LNX.3.91.970113081047.1639A-100000@chaos.analogic.com> "Richard B. Johnson" <root@analogic.com> writes:
>
> >If I execute:
>
> ># ls -R /mnt
>
> >With /mnt containing a MS-DOS file system. The result can't be saved because
> >of the panic that results. Basically, there are a bunch of "Queue full"
> >messages, followed by timeout messages, followed by SCSI reset then aborting
> >the SCSI command messages, followed by 'aiee freeing interrupt', going
> >down hill from there.
> [...]
> >The basic reason for the crash is that the SCSI device is being asked
> >to read beyond the physical end of the media. I verified this by hacking
> >the code. A sector-number of 0xA0001AFF starts this off with my MS-DOS
> >file-system. The media only contains 4406960 512 byte sectors, i.e.,
> >0x433EB0. I think there is a signed/unsigned problem somewhere in
> >the code........
>
> This is very odd. I have a 1 gig dos (vfat) partition on my 2 gig scsi
> drive and I can do the above test without a problem. I wonder if the
> problem is with the aic driver or the msdos file system code.
>
> As to the scsi tape problem, have you tried lowering the bus negotiation
> speed on the card for the exabyte. As someone else noted, there's no
> problem with Archive DAT's at all. I use one regularly on my 2940.

The kernel messages say "Synchronous at 4 MHz" for the CD-ROM, 10 MHz for
the disks, and "Refusing synchronous negotiation" for the tape. This is
correct. Async transfer is done at whatever speed (non setable) the
controller/bus/device allows (the handshake controls the speed).

The MS-DOS file-system does not crash if I mount a 330 megabyte partition.
I think the problem starts at 524,288 * 1024 bytes (hint, hint).

Cheers,
Dick Johnson
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Richard B. Johnson
Project Engineer
Analogic Corporation
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