30 Apr
2011
30 Apr
'11
11:43 a.m.
On 30/04/11 02:29, Chuck Guzis wrote:
The original TRS-80 5.25" drives (even as late as the M4) were, by
default, single-sided, and formated to 35 tracks only. Needless to say
everybody formatted them to 40 traceks to get a bit more storage capactiy
(I've yet to fidn a M3 or M4 fitted with drives that couldn't handle 40
tracks).
My guess is that what you have is a pre-formatted PC disk which was
reformatted for use on the TRS-80. This would expalin why side 1 has a
PC-like format.
The M4 version of TRS-DOS (which is LS-DOS, really), and the disk
contorller hardware, can easily hadnle 80 cylinder drives and
double-sided operation. Many TRS-80s had such drives added to them
(although keeping a 40 cylinder drive as :0 (the boot drive) was also
common for compatibility).
-tony
On 30 Apr 2011 at 1:09, Philip Pemberton wrote:
18/256 looks more likely.
The head-zero tracks all have far more than 9 sectors on them. With so
many sectors it's hard to tell, but 18 seems plausible based on the
inter-sector gaps.
Those 9/512 sectors look suspiciously like DOS 360K tracks... though
what I don't get is why every track is formatted like that. DOS 360K is
only 40 tracks. Unless it was read in a 40-track drive..? Hmm. I've got it listed as "TRS-80 Model
4P" in my catalogue. Maybe I
need to feed it through one of the decoders and see what happens...
Well, there *was* a Mod 4 CP/M format that was 8 sectors of 512
bytes, but no 9 AFAIK.