High Performance Disk Systems
Greg Wettstein
NU013809 at NDSUVM1.BITNET
Sat Jan 6 01:56:17 AEST 1990
Greetings to everyone on the net and I hope the New Year is treating everyone
well.
I am in the process of putting together what eventually has to be a fairly
high-performance XENIX system. This machine will support a large database
(internally developed) and must support queries from numerous users. The
system is based on an ALR 386/220 (20 Mhz) with 6 megabytes of RAM running
XENIX 2.3.3 (VPIX Update A modification). The disk system is a WD1006-MM1
driving an 80 Megabyte Micropolis and a 20 Megabyte Seagate Drive.
The next step in development has to be to put a lot more disk capacity on this
machine. I am looking at CompuAdd's caching ESDI controller and the 320
Megabyte CDC (Imprimus) drive with 14.5 msec access time. I have the following
concerns (questions) which I would be interested to have the nets' reflections
on:
1.) Where is technology going? I am in a quandary whether to go with ESDI
or SCSI. Expandibility is a concern but not overwhelmingly so. I do
need high-performance so I am definitely interested in a caching
controller system. The only such controllers (DPT and CompuAdd's) I
have seen seem to be exclusively ESDI. I have heard rumors about the
possibility of a caching SCSI controller but know of no imminent
product announcements. Comments???
2.) How do people feel about the CompuAdd controller. I have heard good
reviews about the DPT controller but the CompuAdd controller is
attractive from a pricing standpoint. I have seen people mention that
they are trying them but I have heard no reports about performance or
problems. I would be interested (as I am sure the net would be) in
someone who has plugged one in and let it play.
3.) Are special drivers needed to make these controller's work with XENIX
386 2.3.(23) or do the controllers provide a simulation of an ST-506
interface to the operating system? I talked with the technical support
people at CompuAdd and they assured me that it would work as is with
XENIX. My doubts are based on 15 years of experience with technical
support people and the Wettstein Corollary:
"If a computer(technical) person called me up at 2 o'clock
in the morning and told me it was dark outside, I would
send six people out to check"
Cynical, in this marketplace, you bet......
I know that SCSI requires the GT upgrade but I am not sure about
ESDI and these controllers. Comments, reflections??
4.) I know that XENIX will support two disk controllers if the
controller's are jumpered to different port addresses. I am
wondering whether or not this controller will co-exist with the
Western Digital controller currently in the machine. My experience
with mainframes and other systems has shown me that adding another
controller to DASD array's can result in big performance benefits,
i.e. isolation of OS, swap, paging and user data areas. Experiences?
5.) How many things can I expect to have break if I go with the proposed
setup. Cynical, see comment area three.
6.) Should I buy a tape drive or should I be saving my money to buy lots
of floppies. -)
I would be interested in any and all experiences that the net would be
willing to share with me. Responses either to the net or e-mail would be
fine. Considering this week's comment on private responses maybe we should
emphasize net responses more... Once again thanks in advance for any
information which may be forthcoming.
As always,
Dr. G.W. Wettstein
NU013809 at NDSUVM1
"The truest mark of a man's wisdom is his ability to listen to other
men expound their wisdom."
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