Tandon TM 100 5 1/4" drives

From: Don Maslin <donm_at_cts.com>
Date: Tue Oct 19 01:29:34 1999

On Mon, 18 Oct 1999, Bill Sudbrink wrote:

> > The drive don't care. It's the media that is important in this case as
> > soft sector has only one index hole and the hard sector for NS* uses
> > 11 holes(index plus sectors).
>
> Ah... That makes sense. Although I thought that the index hole
> was in a different position. Is the same (drive don't care) true
> for 8 inch drives as well?
>

Well, the Shugart 801s and 851s had a jumper that permitted selecting
between 800/850 characteristics and 801/851 characteristics. The
difference is hopefully explained by the following:
 
> Some of the old 8" drives (Shugarts included) did have the hard-sector
jumpers, but that was to accomodate a peculiarity in the 8" interface.
An 8" drive in hard-sector mode delivers both an index and a sector
pulse. Mostly, the hard-sector jumpering brought into play a couple of
one-shots. Unlike the READY signal, this was never carried over to the
5.25" drives. The READY signal, oddly enough, wasn't present on the
Shugart 400 5.25" original, but was added when 100 tpi drives came along.
Now, most drives with more than 40 cylinders offer an option setting
(even if it's a trace cut) to select disk change or ready. Few 48 tpi
5.25" drives, however, do. One surmise is that this was to make
migration from 8" drives easier.

                                                 - don

 
Received on Tue Oct 19 1999 - 01:29:34 BST