Heatkit 5 1/4 floppies

From: Richard Erlacher <edick_at_idcomm.com>
Date: Thu Apr 8 12:50:01 1999

8" drives typically spun all the time, as their motors were AC types. If
your 5-1/4" drive spins all the time, something's wrong. They had a
nMOTOR_ON signal which you can monitor to determine whether it's a defective
drive or a bunged-up driver. One important reason for the popularity of the
smaller drives over the AC-powered 8" types was noise. If the drive is
running all the time, clearly there's something wrong. It could be in the
jumpering of the drive or in the controller firmware. It could even be a
jumper option on the controller. You'll ruin lots of floppies in a drive
which doesn't stop and which doesn't unload its heads. It's easy to monitor
the control signals. If the controller tells the disk drive to keep
spinning, you need to "fix" the BIOS code.

Dick
-----Original Message-----
From: Joe <rigdonj_at_intellistar.net>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Thursday, April 08, 1999 9:13 AM
Subject: Re: Heatkit 5 1/4 floppies


>At 09:43 PM 4/7/99 -0700, you wrote:
>
>People today don't realize that the old
>>systems used a floppy like present systems use a hard drive, almost all
the
>>time, which is a heck of a lot of wear for a contact media.
>
> I used to work for Burroughs and they had a computer that used 8"
>floppys that spun continously. Burroughs said to replace the disks every
>100 hours. I have no idea how long they would actually run before failing.
> Does anyone know? I have a CPM machine that spins it's 5 1/4" disk
>continously but I haven't run it enough for a disk to fail.
>
> Joe
>>
>>
>
Received on Thu Apr 08 1999 - 12:50:01 BST