Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ucbvax!POSTGRES.BERKELEY.EDU!dillon
From: dillon@POSTGRES.BERKELEY.EDU (Matt Dillon)
Newsgroups: comp.sys.mac
Subject: Re: Reeks on Disktimer (LONG)
Message-ID: <8811082149.AA27845@postgres.Berkeley.EDU>
Date: 8 Nov 88 21:49:17 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 18


	Well, the way I see it (reading the two articles), DiskTimer is
absolutely useless when applied to real-world file handling.  However,
DiskTimer isn't so bad as to preclude low-level performance comparisons
between two drives... sort of the "potential" performance.

	It has been shown that when a filesystem makes multi-block requests
to the lower level driver, performance increases in a non-trivial way.  For
example, BSD unix 4.1->4.2 did this (plus fixed the disk layout) and got
at least a 10x improvment.  C-A (Commodore-Amiga) did this and the transfer
rate through the filesystem went from 60K/sec to 600K/sec.

	So, assuming Apple decides to apply similar fixes to their
filesystem module, one ought to expect real-world numbers in the same
general category as DiskTimer's results.  When such a fix eventually
appears one can bet the low level performance of your HD will make a
big difference.

					-Matt