I have been looking at this answer for a while now and I must say, I do not
understand it.

"The Bus Controller is still FWSCSI to the host, but Ultra SCSI to the disk
devices. How's that for backwards? :)"

Now, how is that for confusing.  I do not believe there is such a thing as
"appearing as a FWSCSI to the host." My understanding of SCSI is that the host
adapter hides the SCSI stuff from the system.  The adapter takes care of
talking to the disc drives and other devices without ever bothering the CPU.
 So there really is no such thing as appearing as an Ultra-SCSI or as a
differential or single-ended SCSI to the CPU.  I believe that apart from Wide
VS Narrow, there really is no difference.

On the other hand, you can attach any type of SCSI devices together (provided
they are either all differential or all single-ended or all LVD.)  The chain
will run at the speed of the slowest peripheral.  So you can have a regular FW
SCSI device in a chain with Ultra SCSI-3 devices, but overall the speed will be
the speed of the FW device.  So in your example, yes, you can plug in Ultra160
SCSI devices to you FW adapter, and they will run at regular FW speeds, not the
other way around.

Kind regards,

Denys. . .

Denys Beauchemin
HICOMP
(800) 323-8863  (281) 288-7438         Fax: (281) 355-6879
denys at hicomp.com                             www.hicomp.com


-----Original Message-----
From:   Mark Landin [SMTP:[log in to unmask]]
Sent:   Friday, May 19, 2000 8:32 AM
To:     [log in to unmask]
Subject:        Re: 12H Array

On Thu, 18 May 2000 17:28:02 -0400, Donna Garverick
<[log in to unmask]> wrote:

>Dennis Heidner wrote:
>
>> The HVD10, is a dual bus box like the HAAS, with redundant fans, power
>> suppies, etc, but it also has 10 hot swappable, slots instead of 8, and
>> it supports the newer faster (30%) SCSI Ultra-Wide drives, with zillions
>> of bytes of storage.
>
>but mpe doesn't do ultra-wide.....          - d

The Bus Controller is still FWSCSI to the host, but Ultra SCSI to the
disk devices. How's that for backwards? :) However, you can replace
the FWSCSI controller with an Ultra controller and all-of-a-sudden you
have an SC10, not an HVD10.

I wish SOMEBODY made something faster than FWSCSI for the 9x9 systems
(and the K- and D- class HSC systems on the 9000 side). I'm having
this very discussion over on comp.sys.hp.hpux. The options are few ...
as in zero, as far as I know.