Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.sys.apple2
Subject: Re: My DMA SCSI question
Message-ID: <13552@smoke.BRL.MIL>
Date: 14 Aug 90 16:53:32 GMT
References: <0093B284FE618EA0.00000111@dcs.simpact.com>
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 13

In article <0093B284FE618EA0.00000111@dcs.simpact.com> whitewolf@gnh-starport.cts.com (Tae Song) writes:
>Although I could be wrong, I don't think 1:1 interleave is the best for Apples
>DMA SCSI card.  It's probablely best to try out different interleaves though.
>MFM has 17 sectors per track, RLL has 28 (normally) and up to 34 sectors track
>and there's one drive with 47 sectors per track.  Now, RAMFast is the only
>controller that can handle that much data that fast.  I know Apples DMA can't
>do 1:1 on RLL drives.  MFM drives maybe 1:1 or 2:1.

The recording modulation method is not very relevant; what is more relevant
is that there is a SCSI controller between the SCSI bus and the read/write
electronics.  If the SCSI controller has full-track buffering, for example,
then there is no point at all in trying to use other than 1:1 virtual
interleave.