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From: kimery@wdl1.UUCP (Sam Kimery)
Newsgroups: net.unix-wizards
Subject: Re: How many users on an 11/73?
Message-ID: <491@wdl1.UUCP>
Date: Sat, 13-Jul-85 00:04:52 EDT
Article-I.D.: wdl1.491
Posted: Sat Jul 13 00:04:52 1985
Date-Received: Wed, 17-Jul-85 06:04:50 EDT
References: <223@thunder.UUCP> <460@wdl1.UUCP> <173@motel6.UUCP>
Organization: Ford Aerospace, Western Development Laboratories
Lines: 36

> In article <460@wdl1.UUCP> kimery@wdl1.UUCP (Sam Kimery) writes:
> >
> >users) These 24 users were logged in always, and we had better response
> >time than an 11/70 with one or two users.  This was running RSTS (ugh!)
> >with rsx and rt-11.
> >
> 
> I would say that it all depends on your i/o systems.  I have an
> 11/73 with dlv11 serial interfaces and a 5.25 inch hard disk system
> running through a xebec card.  The serial interfaces are
> per-char interrupt on input and output.  9600 baud max speed before
> the cpu saturates.  The xebec card has 1Mbit transfer rate, compared
> to the ST506 5Mbit transfer rate and the SMD 18Mbit transfer rates
> on real computers.
> 
> I wouldn't think of putting more than 2 users on a system like this.
> The 11/73 is a great cpu but the i/o system takes more out of
> the computer than the cpu puts back in if you aren't careful.
> Oh, this is running 2.9 unix with only 1/2Meg of memory, not that
> it ever swaps but...
> 
	The first suggestion that I have comes straight from DEC
(ooooh boy, here we go ....)  DONT mix DZ & DH cards, the result is
a VERY brain damaged system that runs slower than my deisel rabbit.

We chose to run the RC-25 drives.  (26M fixed and 26M removable).
These run on the average of 3 - 5 times faster than RL02's.  The
RC-25 drive has both the fixed and removable portions on the same spindle
(UGH!).  We were running DECTAP (manf & dist. package) with all 24
terminals at 19.2Kb.  

We were also running 1.5M of memory.

	Maybe we were just lucky........(?)

			Sam Kimery