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From: jlohman@frankenix (Jeff Lohman)
Newsgroups: net.micro.att
Subject: Re: AT&T MIPs Claim
Message-ID: <16@houligan.UUCP>
Date: Tue, 3-Jun-86 11:35:50 EDT
Article-I.D.: houligan.16
Posted: Tue Jun  3 11:35:50 1986
Date-Received: Sat, 7-Jun-86 04:45:42 EDT
Organization: Gould Electronics, Ft. Lauderdale, Florida.
Lines: 43

>	 I just read some trade rag that had an ad in it from Ma Bell about
>	the UNIX PC.  They made this interesting claim that the UNIX PC gives
>	you "75% of the power of a VAX 11/780" for "only 7% of the cost".
>	Arrgh.  Come on guys.  If I wanted to hear propaganda I'd plug Intel
>	into one ear and Motorola in the other.  Is this the MIP rating for the
>	68010 as compared to the VAX?  Looks like it.  One really couldn't ask
>	for a better example of the Meaningless Index of Performance.  I've seen
>	many a 780 run with more than 20 users.  I'd like to see you put that
>	many on a UNIX PC that I found can barely support one.

For what is worth, here is a subset of the Dhrystone Version 1.1 results posted
to the net in April 1986 comparing the UNIX PC against the VAX 11/780:

*----------------DHRYSTONE VERSION 1.1 RESULTS BEGIN--------------------------
*
* MACHINE	OPERATING	COMPILER	DHRYSTONES/SEC.	% VAX 
* TYPE		SYSTEM				NO REG	REGS	NO REGS  REGS
* ------------- ------------	-----------	--------------- -------------
* ATT PC7300	UNIX 5.0.3	cc		 973	1034	68.7	 71.8
* VAX 11/780	UNIX 4.2BSD	cc		1417	1441

In theory, this benchmark factors out system load effects and compares 
CPU/Compiler horsepower running "typical" code. On this basis, the claim of
75% VAX performance is not totally out in left field.

Multiuser performance is more a function of I/O and Memory capabilities than
CPU speed. Of course the UNIX PC can't support 20+ users because it doesn't 
have these capabilities. It wouldn't be a PC with a PC price if it did.

The main point being made is that PCs can now deliver most of the CPU 
horsepower of older superminicomputers at a fraction of the cost to a small
number of users. The UNIX PC is not unique in this respect, as other PCs compare
even more favorably with the VAX.

Now, if you want to make the UNIX PC look really bad, run Whetstone on it.

--

Jeff Lohman                             ...!{brl-bmd,pur-ee,sun}!gould!jlohman
Gould Inc., Computer Systems Division
6901 W. Sunrise Blvd.  
Ft. Lauderdale, FL 33310-4499
(305) 587-2900 x5237