Hi,
My question:
On Sat, 30 Aug 1997, Thomas Leitner wrote:
> I wonder which PCI SCSI controller is better for Digital Unix: A plain NCR
> based card or a Qlogic ISP1020.
Actually I forgot to emphasize that I'm after a cheap third party
controller but it looks as if there is no such thing based on the ISP1020
and the NCR is hogging the PCI bus.
One promising pointer I got is to
http://www.intraserver.com. A company
who makes high performance SCSI cards. They do not say which chip they
employ but the web pages talk about Digital Unix drivers so I suppose
booting is not possible using their controllers.
All in all it looks as if I'll have to contact my DEC sales rep. for a
DEC card.
Thanks to: berc_at_pa.dec.com
"Alan Rollow - Dr. File System's Home for Wayward Inodes."
<alan_at_nabeth.cxo.dec.com>
Randy Perry <randyp_at_aspsys.com>
Here are their replies:
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>From berc_at_pa.dec.com Wed Sep 3 20:37:31 1997
The NCR card is horrible. The Qlogic ISP1020 series cards are quite
good.
lance
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From: "Alan Rollow - Dr. File System's Home for Wayward Inodes."
<alan_at_nabeth.cxo.dec.com>
It depends on which SCSI features you want. First, if you're looking
at 3rd party cards make sure they offer a driver or include a guarentee
that one of our driver works with it. I've read that some of the
3rd party NCR 810 based adapters will work with our driver, but I
don't think we go much out of our way to make sure they work.
The two supported NCR based adapters are the KZPAA and, I think, the
KZPSA. The KZPAA is Fast, Narrow and single-ended. The one problem
with this adapter is that each command requires a script that the
adapter gets from host memory. If the I/O load involves many small
commands, the script fetching load could dominate the transfers.
The KZPSA offers Fast, Wide and Differential. The ISP1020 adapters
are best represented by the KZPDA which is Fast, Wide and single-
ended. If you have Wide devices you want one of these two. If
the device is single-ended and you can keep it close to the host,
the KZPDA is probably cheaper. If the device is differential go
with the KZPSA instead of the extra cost of a DWZZB to convert
from single-ended to differential. There may be a variant of the
KZPDA that includes Ethernet (KZPSM?).
If you have an 8200 or 8400, the KFTIA offers three ISP1020 differential
adapters and one single-ended one. I once heard that the ISP1020 adapters
had less overhead in command handling and were better for heavy loads,
but I heard anything after that to prove it.
The choice really depends on what SCSI features you want. If you
don't have wide devices, the KZPAA may be fine, but you have to
watch the command mix. If you do have wide device then you it
depends on whether they're single-ended or differential and you
get to chose between the KZPDA or KZPSA.
--------------------------------------------------------------------------
From: "Alan Rollow - Dr. File System's Home for Wayward Inodes."
<alan_at_nabeth.cxo.dec.com>
I wondered if you meant 3rd party stuff. If the vendor doesn't
provide a driver make sure that *they* guarantee it will always
work with our drivers or don't bother. To the best of my knowledge
I don't think *we* do anything to ensure that 3rd device will continue
to work with our drivers if they happen to work in the first place.
As it happens the NCR 810 based adapters do tend to work with our
driver. I don't know of any others.
--------------------------------------------------------------------------
From: Randy Perry <randyp_at_aspsys.com>
try
http://www.intraserver.com
your welcome!
Randy Perry
Aspen Systems Inc
randyp_at_aspsys.com
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>From berc_at_pa.dec.com Wed Sep 3 20:37:31 1997
Thanks. This was my impression as well. Can you name any ISP1020
based SCSI cards other than DEC brands? I'm after a cheap third
party card and I was able to get a plain PC NCR 810 based card
going with DU 4.0b and now I want the same with an ISP1020 based
card.
I don't know; I bought one from QLogic, but they stopped making 1020-based
cards when they came out with the new generation chip. Around 4.0a
DU stopped working with the straight QLogic card because someone
decided to "improve" the code.
I don't know what the DEC SCSI cards cost, but another 1000 pfennings
is going to be worth it. The NCR cards are much worse than you can
possibly imagine. They absolutely take over the PCI bus, and use
much more memory bandwidth than they deserve.
lance
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Received on Wed Sep 03 1997 - 21:04:01 NZST