21 Feb
2008
21 Feb
'08
8:18 p.m.
On Thursday 21 February 2008 22:55, Chuck Guzis wrote:
On 21 Feb 2008 at 22:30, Dave Dunfield wrote:
Isn't that what the 1541 did?
I do have a preliminary utility I wrote to
extract CP/M files from
ImageDisk CP/M images - Worked very well for me in extracting some CDOS
files, however I didn't get much interest in it so I never bothered to
expand it into a general purpose utility - it is configurable however - I
can make it available if you want to play with it. You will need to
figure out the right parameters for Bigboard disks (the tables for Chucks
22disk might be helpful).
I do have a version of ctod that works from "straight" image files of
floppies (i.e., the sectors appear in consecutive order (no physical
interleave) and in side-to-side ordering. It works for my purposes
(mostly reading images formed from Catweasel maps), but might not
with all formats.
The world of CP/M diskettes is far more complex than simple 22Disk
can manage. There's a special version that I sell where we have to
program the sector mapping algorithm--there are formats that employ
logical cylinder- and side-skewing as well as starting at a central
cylinder and working outwards using alternate traks on either side of
the directory. One or two formats use differently-sized sectors on
each track.
And it also ran a different number of sectors, though as far as I know they
were all the same size.
This isn't even counting the differing recording
methods, such as GCR or
zoned sector packing.
The imagination of CP/M CBIOS authors never ceases to surprise me.
Yes, it's really something, and I remember programs like Media Master and
Uniform to try and deal with it, and being limited in terms of what I could
do to read that stuff since my primary (and for a long while my _only_) CP/M
box was equipped with single-sided drives. :-)
What I'm probably going to have to do at some point is decide on a format I
want to use with that BBII. The time I put it together there seemed to be an
assumption that one would be using 8" drives, I think that's what they gave
you the BIOS and their version of CP/M on, but I'd put it in a box with a
couple of 5.25" drives. These days I think perhaps 3.5" HD floppies might be
a better choice since I have so darn many of them (both disks and drives) on
hand here. You can't even find 5.25" drives that easily any more, never
mind 8", and I haven't looked for the media for them for ages.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin