Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!mordor!sri-spam!ames!pasteur!agate!gershwin.berkeley.edu!cswarren
From: cswarren@gershwin.berkeley.edu (Warren Gish;133B Biochem;x3-9219)
Newsgroups: comp.sys.mac
Subject: Re: A/UX disk I/O (real numbers)
Message-ID: <7215@agate.BERKELEY.EDU>
Date: 26 Feb 88 22:31:35 GMT
References: <8802251936.AA23485@cory.Berkeley.EDU>
Sender: usenet@agate.BERKELEY.EDU
Reply-To: cswarren@gershwin.berkeley.edu.UUCP (Warren Gish)
Organization: University of California, Berkeley
Lines: 17

> 					Amiga	Amiga	Mac-II	Sun
> 					Floppy	CLtd	A/UX	3/50
> 					df1:	dh0:	HD80SC	
> 
> Read speed,    512 buffer (byte/sec)	11014	17133	55168	240499
> Read speed,   4096 buffer (byte/sec)	12024	17133	53708	234057

Under the MacOS on a MacII configured with an 80 MB CMS Pro80ii (Quantum)
disk drive, I get a read speed of about 512 Kilobytes per second
using a buffer (not cache) size of 32 KB (see PBOpen in IM or setvbuffer()
under MPW C), while reading an unfragmented 8+ Megabyte file.  With a buffer
smaller than about 31 KB, the read speed drops dramatically to about
32 KB/sec.

Warren Gish
IST
UC Berkeley
cswarren@violet.berkeley.edu