Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!seismo!nbires!isis!ico!ism780c!tim
From: tim@ism780c.UUCP (Tim Smith)
Newsgroups: comp.sys.mac
Subject: Re: Why is A/UX disk I/O only 50KB/sec?
Message-ID: <6976@ism780c.UUCP>
Date: Fri, 24-Jul-87 16:38:35 EDT
Article-I.D.: ism780c.6976
Posted: Fri Jul 24 16:38:35 1987
Date-Received: Sat, 25-Jul-87 23:37:32 EDT
References: <2363@ames.arpa> <344@swanee.OZ> <777@unccvax.UUCP>
Reply-To: tim@ism780c.UUCP (Tim Smith)
Organization: Interactive Systems Corp., Santa Monica CA
Lines: 47

In article <777@unccvax.UUCP> cbenda@unccvax.UUCP (carl m benda) writes:
< In article <344@swanee.OZ>, gustav@swanee.OZ (Gustav) writes:
< > In article <2363@ames.arpa>, jaw@ames.arpa (James A. Woods) writes:
< > > During Phoenix USENIX, at the Unisoft booth, on the Mac II,
< > > a "time cat /usr/dict/words > /dev/null" took about four seconds
< > > of clock time. 
< > Well, let me compare this to our VAX 11/750 running 4.2BSD. The disk
< > we use is RA81:
< >    real	0m31.53s
< >    user	0m4.61s
< >    sys	0m2.26s
< > The system at the moment has 5 users and the load is 4.2. 
< > Mac II wins a long way!
< 
< Please multiply Mac II time by 5 then add the operating system overhead time
< necessary for time slicing to simulate the time necessary for
< five users...

Nope, you don't have to do that.  The significant time on the multi-user
system is user + system time.  That is relatively independant of load.
The load affects the real time. 

Thus, the above vax would not get much better than 4.6 + 2.3 seconds
even if it were single user.  I don't know why that vax is so slow.
Here is what I get on a 780 running 4.3:

	Script started on Fri Jul 24 13:34:12 1987
	388. wc /usr/dict/words
	   24259   24259  198596 /usr/dict/words
	389. time cat /usr/dict/words > /dev/null
	real    0m1.00s
	user    0m0.00s
	sys     0m0.40s
	390. r
	time cat /usr/dict/words > /dev/null
	real    0m1.38s
	user    0m0.01s
	sys     0m0.30s
	391. r
	time cat /usr/dict/words > /dev/null
	real    0m0.96s
	user    0m0.01s
	sys     0m0.26s
	392. exit
	script done on Fri Jul 24 13:34:45 1987
-- 
Tim Smith, Knowledgian		{sdcrdcf,seismo}!ism780c!tim