Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!bu-cs!purdue!decwrl!sun!coherent!dplatt
From: dplatt@coherent.com (Dave Platt)
Newsgroups: comp.sys.mac
Subject: Re: Rodime performance with new driver
Message-ID: <12214@coherent.com>
Date: 19 Oct 88 17:28:02 GMT
References: <431@nikhefk.UUCP>
Reply-To: dplatt@coherent.com (Dave Platt)
Distribution: comp
Organization: Coherent Thought Inc., Palo Alto CA
Lines: 39

In article <431@nikhefk.UUCP> paulm@nikhefk.UUCP (Paul Molenaar) writes:
> Immediately after noticing the new Rodime installer/driver software
> showed up on the net, I downloaded the program and installed
> it on my Rodime 45Mb drive for my SE. I formatted the driving using
> an 1:1 interleave (that's what the program advised me to do).
> I created four partitions and went thru the hours long process
> of reinstalling all software.
> 
> Then I ran Disktimer II, which showed me shocking results. The drive's
> writing performance decreased dramatically. Now: >660 (whereas
> the Dataframe list shows something like 55). I knew the Rodime
> was slower, even with the older driver, but this is terrible...

The figure you're seeing (660 vs. 55) is strong evidence that the drive
is too fast for the SE at a 1:1 interleave... it's missing sectors on
every read, and is probably taking 12 revolutions to transfer the data
rather than 1.

I'm rather surprised that the formatter recommended a 1:1 interleave
for a drive on an SE.  From what I understand, only a very slow drive
can be run at 1:1 on an SE without sectors being missed.  Do you recall
what the formatter said was the actual interleave on the disk _before_
you reformatted?  I'd bet fairly heavily that the old Rodime formatter
had laid down a 2:1 interleave.

I reformatted the 100-meg Rodime on my Mac II using the new driver; the
DiskTimer II results (40/40/15) were within 1 point each of the old
values.  So, I don't think there's anything in particular wrong with
the driver.

I suggest that you reformat at a 2:1 interleave, and then run DiskTimer II
before restoring the whole drive.  You'll almost certainly find that the
drive's performance has returned to normal.

-- 
Dave Platt                                             VOICE: (415) 493-8805
  USNAIL: Coherent Thought Inc.  3350 West Bayshore #205  Palo Alto CA 94303
  UUCP: ...!{ames,sun,uunet}!coherent!dplatt     DOMAIN: dplatt@coherent.com
  INTERNET:   coherent!dplatt@ames.arpa,    ...@sun.com,    ...@uunet.uu.net