From: root@uunet!scarrow (Superuser)
Subject: Re: 8" disk drives
Organization: TCI
Date: Fri, 01 Jan 1993 23:06:57 GMT

In article <1993Jan1.074726.3972@neb> bbs@neb (BBS System 801-572-4969)
 (James King) writes:

> I've recently come into contact with numerous IBM style (old
> mainframe/teletype) 8" disk drive mechanisms (dual drive cases). Are
> these usable with the ATR8000 (or MIO)? If so, what software would/could
> be used to format out those monster disks? I've noticed that the disks
> themselves are notated as: Double sided, double density. Does that
> indicate 360k of storage? I've heard rumors of 1.2meg 8"
> disks/drives. 

I've had a few 8" disk drives attached to a ATR-8000, but I can't give you any
info on the MIO. A single sided drive will yield over 500KB, and a DS/DD one
will yield over 1MB. They are formated to 77 tracks, thus you should use MyDos
(or one of a few other DOSs that support this configuration). You can format
the drive (if you wanted to) to be compatible with DOS 2.0, but you would be
stuck with 90K. I prefer MyDos because of sub-directories, as you can easily
get to many files in a single directory when you have over 500KB.

There are, however, some things to note: You will need a power supply, one
that will go to 24V. (There are other voltages needed also, but this one is the
hardest to find). Some 8" drives also require 120VAC to power the main motor.
The next thing to note is that the 8" drives use a 50 pin cable, where as the
controler provides you with a 34 pin, thus you will need an adapter. I bought
mine from SWP (the manufactures of the ATR-8000) for about $15 and modified it
to support multiple drives. The last thing to note is the Head Selects. There
are some jumpers on your 8" drives that say when to select the heads. If for
some reason the heads on both drives get selected simontaniously (sp?), your
power supply will turn to smoke (unless it's a good one). I had a good one, but
every time the heads kicked in, my lights would dim around the house.

Nowdays, I use a pair of 3 1/2" DS/DD drives on my ATR-8000 with a 1050 as the
boot drive. My Shugarts (and the power supply) are in a storage shed, and I
visit them regularly for nastalgic reasons. The point is that I would rather
loose a few hundred K per disk if I don't have to get a hernia lugging the
drives around. 720K 3 1/2" drives go for about $50, and you don't need any
strange adapters or power supplys. Also, you can find 3 1/2" disks at the local
supermarket vs. a military surplus store.

All the information you would need to hook up any type of drive to the ATR-8000
is included in the manual. I don't know if SWP is still around, so I don't know
if you can still get the adapter, but making your own wouldn't be too hard.
There is a good description of how to do this in a very old issue of "Micro
Cornocopia", or you could rough it out with your local computer science library
(just find the pinouts of both types of drives, and play connect the dots).
Finding the power supply is a little more difficult nowdays, you might want to
see if you can grab the supply that was used to run the drives initially (the
place where you got the drives).
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