18 Mar
2014
18 Mar
'14
6:34 p.m.
Well, I'm embarrassed. The Teac units are indeed 35-track drives with
deathly slow seek rates. Just finished formatting, reading and writing a
couple of diskettes under IMD.
I had already tried slowing down the step rate as far as 10ms, but never
went any further since I had never encountered a drive any slower than
that. This is a lesson I won't forget!
Thanks again to all.
Steve
--
18 Mar
18 Mar
6:58 p.m.
On Tue, 18 Mar 2014, Steven Hirsch wrote:
Well, I'm embarrassed. The Teac units are indeed
35-track drives with
deathly slow seek rates. Just finished formatting, reading and writing a
couple of diskettes under IMD.
I had already tried slowing down the step rate as far as 10ms, but never
went any further since I had never encountered a drive any slower than
that. This is a lesson I won't forget!
There are SOME drives that can barely keep up with 25ms, or even 40ms.
When IBM used the Qumetrak 142 in the "portable PC" (Compaq style
luggable) and PCJr, they had to change the parameters from PC-DOS 2.00
to PC-DOS 2.10 to handle the slow drives.
In Teac drives, A seems to be 48tpi single sided, B 48tpi double sided
(aka 360K), and F is 96TPI DS. G is 96tpi "high" density (aka 1.2M). I
don't know whether D or E is 96tpi single sided.\
Whereas, on Tandon drives, -1 is 48tpi SS, -2 is 48tpi DS, -3 is 96tpi SS,
and -4 is 96tpi DS. (-4M is 100tpi (Micropolis))
SO, . . .
50A-3 shows the problem of incompatible numbering conventions
Great catch by Chuck!!
7:31 p.m.
On 03/18/2014 03:58 PM, Fred Cisin wrote:
In Teac drives, A seems to be 48tpi single sided, B
48tpi double sided
(aka 360K), and F is 96TPI DS. G is 96tpi "high" density (aka 1.2M). I
don't know whether D or E is 96tpi single sided.
The FD50 seems to use this convention, as far as I can tell. A=48tpi/1
B=48tpi/2 C=100 tpi/2 D=100tpi/2 E=96tpi/1 F=96tpi/2. I don't know if
there was a 50G, however. (The Sord used FD50C drives)
That's as far as I can tell. Fortunately, there aren't too many of
these old slow buggers around to get a verifiable sample. They were
twitchy even when they were new.
--Chuck
7:45 p.m.
On 03/18/2014 05:58 PM, Fred Cisin wrote:
In Teac drives, A seems to be 48tpi single sided, B
48tpi double sided
(aka 360K), and F is 96TPI DS. G is 96tpi "high" density (aka 1.2M). I
don't know whether D or E is 96tpi single sided.\
Whereas, on Tandon drives, -1 is 48tpi SS, -2 is 48tpi DS, -3 is 96tpi SS,
and -4 is 96tpi DS. (-4M is 100tpi (Micropolis))
Did anyone ever attempt to make a list of floppy drives by vendor/model, in
a similar way to the lists for ST506/412-type hard drives which used to be
floating around years ago? I don't remember seeing one, but that doesn't
mean to say that such an animal didn't exist.
(I have seen partial lists, but typically for one or two vendors as used on
one or a small handful of systems, nothing comprehensive)
Jules
7:56 p.m.
On 03/18/2014 04:45 PM, Jules Richardson wrote:
Did anyone ever attempt to make a list of floppy
drives by vendor/model,
in a similar way to the lists for ST506/412-type hard drives which used
to be floating around years ago? I don't remember seeing one, but that
doesn't mean to say that such an animal didn't exist.
Mike Farris' list seems to be the best online one available, but does
not include everything (the FD50 is missing, for example) and doesn't
include any detail--but it's a start.
--Chuck
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participants (5)
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aek＠bitsavers.org -
cclist＠sydex.com -
cisin＠xenosoft.com -
jules.richardson99＠gmail.com -
snhirsch＠gmail.com