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