hard-sector 5 1/4 disk

From: Fred Cisin <cisin_at_xenosoft.com>
Date: Tue Oct 30 16:53:14 2001

On Tue, 30 Oct 2001 UberTechnoid_at_home.com wrote:
> I recall the Amiga having a high-density external disk addon that ran at
> 1/2 speed so Commodore wouldn't have to include a faster fdd controller
> chip. The bad news. The good news is that it worked on all Amiga
> machines right out of the box.

How was reliability for it? The Weltec half speed 1.2M 5.25" did NOT work
well.

> The ATR8000 and ATR8500 CP/M boxes DO for Certain use the index hole to
> time the drive's rotation to determine if it is an 8" or a 5.25" mech
> running. I've used a couple of 3.5" high-density drives on them and
> gotten up to 1.35mb in CP/M and 1mb in Spartados. The trick is getting a
> 3.5" mech that has a big ol' block of jumpers on it. You can fiddle with
> the jumpers and make the drive emulate a 77track 8" mech.

The REAL easy (just a weird cable) is to put a 5.25" 1.2M in place of an
8". Same speed, same data transfer rates, etc.

> As for the index hole, this wasn't such a bad thing unless you wanted to
> use 'flippy' disks in an ATR. Atari drives don't use the hole at all so
> flipping the disk works fine. With the ATR as a controller though you
> have to punch another index hole in the disk or use a standard mech with
> dual sets of index hole sensor such as those 'flippy' drives made by
> Pertec and Aerocomp -never seen em', I just know they made them.

Ah, yes.
I manufactured and sold a jig for marking and punching. The first product
that I had that ever got any free ink (in Dr. Dobbs)


> And then there are these freaky 3" disks I have for an Amstrad I once
> owned.....

Nice, aren't they?
But, if you have a DS drive, then it won't let you flip the disks (as you
could with a SS drive; thus resulting in an inability to read second sides
using a DS drive.


3.25" was another fun one. Pushed by Dysan, it was made like a
"normal" floppy.

--
Grumpy Ol' Fred        cisin_at_xenosoft.com
Received on Tue Oct 30 2001 - 16:53:14 GMT

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