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From: bobmon@iuvax.UUCP (Robert Montante)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Mainframes vs micros
Message-ID: <2345@iuvax.UUCP>
Date: Sun, 4-Jan-87 13:32:18 EST
Article-I.D.: iuvax.2345
Posted: Sun Jan  4 13:32:18 1987
Date-Received: Mon, 5-Jan-87 02:36:10 EST
References: <653@imsvax.UUCP> <196@unisoft.UUCP> <2841@gitpyr.gatech.EDU>
Reply-To: bobmon@iuvax.UUCP (Robert Montante)
Organization: Indiana University, Bloomington
Lines: 39

> robert@gitpyr.UUCP (Robert Viduya):
>>curt@charming.UUCP (Curt Mayer):
>> Give me a break.  I have never seen a CDC cyber with more than 05% load. 
>> This is in a university environment with 700+ users, no less.
>
>Is this 700+ simultaneous online users or just 700+ users in the validation
>file?  Our main computing engines, two CDC Cyber 855s and one CDC Cyber 990,
>can only handle between a 100 and 200 users on simultaneously (per machine),
>although the validation file has thousands of users in it.

A couple of years ago I worked on an IBM 3090 (probably been upgraded again
by now) that regularly had 400+ users on it.  By regularly I mean that I got
in at 7:30am to get to work because around 8:15am, when the Data Processing
and Stat. Support people had gotten their coffee, the load would hit the 400+
number -- five days a week.  I think the installation had three 3090's, only
two of which were dedicated to interactive processing.  Incidentally, I would
guess that 60% of the terminals on that system were PC's.

In my experience, the 400-user limit was defined by the system response time.
At that number, response was poor enough that additional people would find
something else to do.  Another point:  I would download whatever I could to
the PC, thereby improving response time for me quite a bit.  There was still
quite a bit of work that couldn't be downloaded, either because the software
was mainframe-resident only, or the data were mainframe-resident, or I was
doing something that explicitly involved the networking features of the system.

In short, my experience was that, in large environments, an explosive growth
in the use of personal computers makes life marginally more bearable on the
mainframes.  There is still demand for all the mainframe capacity available,
but more people struggle with the poor response times (instead of giving up
entirely) because many of the smaller jobs move to the local machines.

*-=-*-=-*-=-*-=-*-=-*-=-*-=-*-=-*-=-*-=-*-=-*-=-*-=-*-=-*-=-*-=-*-=-*-=-*-=-*
 Datclaimer: "[Usual disclaimer: I have no opinion, therefore I don't exist .]"
Disclaimer: I opine, therefore I am.  My employer, however, is a figment.

RAMontante
Computer Science				"Have you hugged ME today?"
Indiana University