Path: utzoo!utgpu!watserv1!watmath!att!att!emory!wuarchive!udel!rochester!pt.cs.cmu.edu!o.gp.cs.cmu.edu!andrew.cmu.edu!cs4w+
From: cs4w+@andrew.cmu.edu (Charles William Swiger)
Newsgroups: comp.sys.apple2
Subject: Re: Some observations
Message-ID: <gb==JPO00WAwQ58kZ_@andrew.cmu.edu>
Date: 29 Oct 90 23:03:55 GMT
References: <139800045@uxa.cso.uiuc.edu>,
	<2219@unsvax.NEVADA.EDU>
Organization: Carnegie Mellon, Pittsburgh, PA
Lines: 23
In-Reply-To: <2219@unsvax.NEVADA.EDU>

>Also, I've seen an "InnerExpress" advertised that is
>supposed to increase the speed of Ingenuity's (ST-506)
>hard disks.  Is this a new controller to replace
>the original?  If it is, could you grab any issue of
>_Computer_Shopper_ and build an RLL or MFM (which
>one?) drive to plug into this card?  It'd be a whole
>lot cheaper than SCSI, if it would work.

SCSI is a standard that defines how a drive is supposed to connect to a
computer.  Any computer that can support a SCSI card/port should be able
to use any SCSI drive.  It's why you can buy a Seagate or Miniscribe
SCSI drive for an IBM (much cheaper this way!) and run it on your Apple.

MFM (Modified Frequency Modulation) and RLL (Run Length Limited) refer
to the method by which the drive head(s) read and write to the disk. 
RLL will place about 50% more information on a drive, but there may be
problems with reliability if you have a cheap drive.  Best way to check
whether your drive can handle RLL encoding rather that MFM is to ask the
manufacturer.


-- Charles William Swiger
    cs4w+@andrew.cmu.edu