17 Apr
2001
17 Apr
'01
4:02 p.m.
On 17 Apr 2001, Frank McConnell wrote:
"Fred Cisin (XenoSoft)"
<cisin(a)xenosoft.com> wrote:
I have two 100 tpi drives, a Tandon with an inoperable head and a
Micropolis (I think - machine dismantling required to check). Both of
these drives carry a sticker on the bottom edge of the door that
identify them as 100 tpi. Of course, such stickers are notorious for
falling off also!
- don
On 16 Apr 2001, Frank McConnell wrote:
> Hmm, here I sit looking at one of a pair of Micropolis model 1115-VI.
> It's a 5.25" full-height drive, serial 0372. Someone (not me) helpfully
> wrote on it with a marker:
They might be right. I had heard that Micropolis
came out later with a
96TPI, but I've never seen it. The date code and the double sided is
consistent with that. Is it really 2 sided? What kind of door assembly
does it have?
Looking at it from the front, it looks like a typical full-height
Tandon as seen in an IBM PC or Shugart drive. Flat door, closes down
over center of slot. A printed-circuit board covers the top of the
drive. I think there are two sets of head leads that disappear into
the interior. The door, when closed, has a flange that pokes through
a slot in the board to interrupt an optical emitter/sensor pair. What's funny is that the top hub appears to be
fixed. The bottom hub is
mounted to a sort of sub-frame that pretty much covers the bottom of
the drive, and it pivots (drive shaft, drive motor and all) about the
middle of the outer frame as you close the door.
Of course, this makes looking into the interior of the drive more fun
than usual, because it's completely surrounded by stuff.
But they might be mistaken, and have ASSUMED
96TPI due to it not being
48TPI, and/or having about 80 tracks. I've even seen people label 720K
5.25" drives as being 1/2M, "because it's NOT a 360K".
Yep, that is what you got me thinking.
-Frank McConnell