15 Sep
2013
15 Sep
'13
7:43 p.m.
Fred Cisin wrote:
>Q: Did ALL
DS 8" drives also support SS?
>I was once told that SOME DS drives had the DS index sensor, but no SS
>index sensor!
>Did ANY manufacturer try to cut corners THAT much?
>
>
On Sun, 15 Sep 2013, Jerome H. Fine wrote:
Since the only system I ever used an 8" DSDD
floppy was the PDP-11
using a DSD 880/30 with the (emulated) RX03 drive, I don't have sufficient
knowledge of what any other manufacturers did.
But, at least the floppy drive in the DSD 880/30 definitely had two sensors
with two detection circuits, as mentioned by Tony.
We all know that DEC used a SS / DS drive.
The question is whether there existed anybody who made
DS without the SS
sensors.
My answer is that I do not know!!! The only 8" floppy
drives (and which I agree were used with RT-11 on DEC
systems as far as most of the rest of the hardware was
concerned) that I know about which supported double
sided media ALSO supported single sided media.
Since systems designed to be able to support RT-11
applications probably tended to be competing against
a VERY high priced DEC product, I would imagine
that profit margins for such systems were never that
tight so as to be unable to support both single and
double sided operations.
But I also suppose that some very low priced systems
could have used an 8" floppy drive which supported
double sided operations, but was missing the sensor
which detected single sided media.
The original question had been about an SA800 drive,
and did not mention
DEC.
I understand. I do tend to think that such drives were
often used by third party manufacturers of DEC compatible
hardware.
As for the rest of the computer world, I was aware of
some of what was available, but I did not know many
of the details needed to run most of the other systems.
Jerome Fine