Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!dptg!lzaz!hcj
From: hcj@lzaz.ATT.COM (HC Johnson)
Newsgroups: comp.sys.atari.st
Subject: Re: replacement for tandon 262 in sh204
Summary: You can use any MFM drive and a power supply with the sh204
Keywords: sh204 hard disk
Message-ID: <756@lzaz.ATT.COM>
Date: 25 Aug 89 21:31:16 GMT
References: <4481@hall.cray.com>
Organization: AT&T ISL Lincroft NJ USA
Lines: 41

In article <4481@hall.cray.com>, rosenkra@hall.cray.com (Bill Rosenkranz) writes:
> ----
> i have a sh204 (atari 20 MB) which i'd like to stuff a larger capacity
> drive mech in. the particulars are:
> 
The SH204 circuit boards will support any two MFM drives.
However, its rinky-dink power supply should not be asked to power them.
-- Standalone boxes with power are avail for 20-100 Dollars.
Power supplies alone are $30.

Longer  cables can be obtained from anyone supporting IBM clones, including
Radio Shack.

The formatter HDX will allow any drive to be formatted if you edit its
data file.

SCSI drives are the ones that are requiring special formatting code.

Also, when buying a drive note the following.
Many drives include a bad block list.   Regretably, none of the public
formatters allow you to use it.

Remember that the adaptec 4000 controller (and atari clone) can correct
only a burst of 9 bits, so a drive that shows > 5 bits (or so) in its
error list is likely to come up with a fatal error.

This is doubley unfortunate on the SH204 because it neglects to send the
error back to the Atari. (Berkeley Micro Systems Oakland CA has a fix
for this).

The formatters talk about mapping out errors, but this is valid only
for TOS formatted partitions, and the DATA area only.  Fatals in the FAT
or DIRECTORY will kill you.

Personally, I hacked my Atari formatter to accept a bad block list and
let Adaptec do what its best at; mapping out bad blocks.

Howard C. Johnson
ATT Bell Labs
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