18 Jan
2001
18 Jan
'01
11:44 p.m.
On Thu, 18 Jan 2001, Wayne M. Smith wrote:
> My S/23 Service Manual states that two 8 inch
drives
> were available, the 31SD which was a single sided
FM
> only drive, and the 51TDF which was a double
sided
FM
> or MFM drive. The disks have 77 tracks per side,
and
> data can be written on tracks 1 through 74, with
00
> reserved for labeling and 75 and 76 for
replacement.
>
> Both drives are hard sectored. FM disks can be
> formatted with 8, 15 or 26 tracks, with 512, 256
and
> 128 bytes per track respectively. For MFM the
bytes
per sector are
doubled.
I believe that you mean SOFT sectored, as the number per track in a hard sector disk is determined by the
disk and
is only changeable by using a disk with a different
hole pattern.
FYI, 5.25" disks came in both 10 and 16 sector
hole
patterns,
while 8" were 32 hole only to the best of my
knowledge.
- don
My S/23 manual says the following:
"The location of the access hole for index sensing on a
diskette [type] 1 differs from that on a diskette
[type] 2 and diskette [type] 2D." The 31SD drive can
only read type 1, so I guess you could say it's soft
sectored (I assume it ignores the hole). The 51TD
reads types 2 and 2d, which have the same hole pattern
vis-a-vis each other, but different from a type 1, but
also reads type 1. It distinguishes based on the
location of the index hole, so I would say it was hard
sectored. Then again, in effect it's only determining
DS vs. SS so maybe that's not the same thing. What do
you think?