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From: dyer@wivax.UUCP (Stephen Dyer)
Newsgroups: net.micro.6809
Subject: Re: stuff from May *Rainbow* - (nf)
Message-ID: <19455@wivax.UUCP>
Date: Sat, 28-Apr-84 09:19:45 EDT
Article-I.D.: wivax.19455
Posted: Sat Apr 28 09:19:45 1984
Date-Received: Sun, 29-Apr-84 06:56:42 EDT
References: <3500033@uokvax.UUCP>, <3500034@uokvax.UUCP>
Organization: Wang Institute, Tyngsboro, Ma.  01879
Lines: 20

I can't speak directly from experience, but I've been researching the
hard disk issue, in fact have even purchased a ST506 5mb drive--all I
need now is the controller and CoCo-to-controller interface.

Most all hard disk drive systems will use a SASI-bus miniwinnie controller.
This is a "smart" controller which takes high-level commands (read/write
block #n) and transfers the data to an on-board buffer.  How the data gets
from the controller to the host CPU depends on your host interface, but
generally one can choose a simple programmed-IO interface or a more complicated
DMA scheme.  The easiest scheme for the CoCo would be programmed I/O.

One particular SASI bus controller can handle both a winnie and two floppies.
If you decided to use this with your CoCo, you'd immediately win by eliminating
the crappy disk controller that Radio Shack provides.  Likely, too, you'd
be able to use the same driver for both the floppy and the winchester--that's
how isolated one is from details of the hardware (sectors/track, no of tracks.)
-- 
/Steve Dyer
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