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From: slsw2@cc.usu.edu
Newsgroups: comp.sys.dec.micro
Subject: Re: Rainbow EchoMail Digest
Message-ID: <1991Mar25.170117.47148@cc.usu.edu>
Date: 25 Mar 91 23:01:16 GMT
References: <9103230131.AA04966@remote.dccs.upenn.edu> <1991Mar23.080919.25327@cunixf.cc.columbia.edu>
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In article <1991Mar23.080919.25327@cunixf.cc.columbia.edu>, lasner@shibuya.cc.columbia.edu (Charles Lasner) writes:
>     With the double-density label attached to IBM's stuff, someone dreamt
> up the name "quad-density" for the disks used by the DEC RX50 machines
> and the Victor 9000.

I first saw this notation with the Superbrain, predating both the RX50 and
the Victor 9000 by a number of years.

>     All formats can gain transfer efficiency by including a stagger
> factor in the formatting process like the software mapping of RT-11, etc.
> ...  RT-11 uses a software
> mapping scheme...

Sure wish they'd used a hardware mapping scheme. All floppy controllers
these days can be told which order to lay the sectors out in, so there's
really no excuse for doing it with software. The problem with software is
that if you want to read the disk, you have to know the software mapping
scheme. But if they had just scrambled the order of the sectors on the 
disk you wouldn't have to. Sigh.
-- 
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Roger Ivie

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