12 Oct
1998
12 Oct
'98
11:08 a.m.
Mine was more like the mechanism of either a TRS-80 drive, or an IBM Tandon
drive. The heads were connected to a horizontal stepper by a thin metal
sheet.
--
-Jason
(roblwill(a)usaor.net)
ICQ#-1730318
----------
From: Tony Duell <ard(a)p850ug1.demon.co.uk>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Subject: Re: Picture up (RE: Microsci HAVAC)
Date: Monday, October 12, 1998 4:00 PM
> BTW: I used to have a Disk II, and the heads were positioned by a
stepper
motor, and
didn't have any "spiral-grooved disc" anywhere in the entire
unit.
Odd... I've got a number of Disk II's here, and every one has a stepper
motor under the chassis with a disk on the spindle of it above the
chassis. There's a spiral groove in the disk and a little lug on the head assembly that fits into the groove. The stepper motor
turns the disk and
thus moves the heads.
Maybe there are several versions of the Disk II
-tony
12 Oct
12 Oct
12:37 p.m.
On Mon, 12 Oct 1998, Jason Willgruber wrote:
Mine was more like the mechanism of either a TRS-80
drive, or an IBM Tandon
drive. The heads were connected to a horizontal stepper by a thin metal
sheet.
What's called a "split band positioner".
The first drives that Radio Shack retailed for the Model 1 were Shugart
SA400s, with the infamous spiral grooved "phonograph" disk. Then IIRC, they
switched to Tandon TM100-1, and then later TPI?.
IBM started with Tandon TM100-2. IBM's first half height drives (PC JR,
and Potable PC) were Qume-trak 142.
The FIRST drives for the Apple ][ used a Shugart mechanism with the
infamous grooved disk. I have no idea what they might have used later.
--
Fred Cisin cisin(a)xenosoft.com
XenoSoft http://www.xenosoft.com
2210 Sixth St. (510) 644-9366
Berkeley, CA 94710-2219
1:08 p.m.
"Fred Cisin (XenoSoft)" <cisin(a)xenosoft.com> wrote:
IBM started with Tandon TM100-2.
No, with the IBM PC (model 5150), they started with the TM100-1, a 40 track
single sided disk. In PC-DOS 1.0 they only used 8 sectors per track, for a
total disk capacity of 160K. In PC-DOS 1.1 they added support for the 9
sector format, increasing the capacity to 180K.
IIRC, the dual-sided drives were not available (from IBM) until the
introduction of PC-DOS 2.0.
To this day, the MS-DOS format command still has options for single-sided
and 8 SPT formats.
Eric
1:54 p.m.
> IBM started with Tandon TM100-2.
On 13 Oct
1998, Eric Smith wrote:
No, with the IBM PC (model 5150), they started with
the TM100-1, a 40 track
single sided disk. In PC-DOS 1.0 they only used 8 sectors per track, for a
total disk capacity of 160K.
Absolutely right! I stand corrected.
In PC-DOS 1.1 they added support for the 9
sector format, increasing the capacity to 180K.
IIRC, the dual-sided drives were not available (from IBM) until the
introduction of PC-DOS 2.0.
Actually, it was PC-DOS 1.10 (and MS-DOS 1.25) that provided DS, and 2.0
provided the 9SPT. Thus the 320K format came before the 180K/360K.
There were also unofficial patches for 1.00 to do DS, but using the
second side as if it were another drive.
To this day, the MS-DOS format command still has
options for single-sided
and 8 SPT formats.
SHHHHH! Don't say anything or MS will take out that backward compatibility.
--
Fred Cisin cisin(a)xenosoft.com
XenoSoft http://www.xenosoft.com
2210 Sixth St. (510) 644-9366
Berkeley, CA 94710-2219
13 Oct
13 Oct
5:52 a.m.
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12 Oct
12 Oct
12:53 p.m.
On Mon, 12 Oct 1998, Jason Willgruber wrote:
Mine was more like the mechanism of either a TRS-80
drive, or an IBM Tandon
drive. The heads were connected to a horizontal stepper by a thin metal
sheet.
And you are sure this was a full-height, Apple manufactured, metal
enclosure, black face plate with the colorful apple logo, Disk ][?
Sellam Alternate e-mail: dastar(a)siconic.com
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ard＠p850ug1.demon.co.uk -
cisin＠xenosoft.com -
dastar＠ncal.verio.com -
eric＠brouhaha.com -
roblwill＠usaor.net