1 Feb
2014
1 Feb
'14
4:06 p.m.
On 02/01/2014 02:46 PM, John P. Willis wrote:
I have not tried any DSDD media. I don't have any
at the moment, and
all my drives are DSHD... not sure if the NEC utilities would even
fit on a boot floppy of that size anyway.
IIRC, there were differences in track spacing--or
something to that
effect-- rendering writes to 360K media in 1.2M drives (or was it
vice versa?) problematic.
"1.2M" drives use track spacing at 96 tracks per inch. "360K"
double-sided drives use a 48 track/inch spacing. So, to read and write
DD media, IBM adopted the convention of writing or reading every other
track when in "360K" mode. This works fine if you stay on a "1.2M"
drive, but creates havoc with "360K" drives picking up garbage on the
wider track. This can be avoided if the disk is thoroughly degaussed
(such as by using a videotape bulk eraser) before formatting in a 96 tpi
drive.
But to your problem. The normal configuration for a "1.2M" floppy drive
is to use pin 2 (REDWC) as a density indicator, a high level = low
density; a low level is high density. If the input is NC, or high,
you'll crash and burn on DSHD media.
--Chuck