22 Feb
2022
22 Feb
'22
6:44 p.m.
Corrections:
I think that Mike Gingel did both a program on PC for read/write TRS-DOS
family, AND did one on TRS-DOS for other formats. I don't remember which
one was which, but I think that the one running on TRS80 might
be "Hypercross", with "PC Cross Zap"? being the one running on PC?
http://www.oldcomputers.it/parts/r/radio/TRS80_4/docs/trs80-xf.htm
Roxton Baker was the author of TRAKCESS. I remember Alan Gelder (TBug
enhancements) helped Baker with the machine language portions.
https://www.classic-computers.org.nz/system-80/software-manuals/manuals-tra…
Harv Pennington's first book (before he got carried away) was "TRS80 Disk
And Other Mysteries". Later on, he even got involved in marketing
a port of Michael Shrayer's "Electric Pencil" to PC!
On Tue, 22 Feb 2022, Fred Cisin via cctalk wrote:
On Tue, 22 Feb 2022, Bill Gunshannon via cctalk
wrote:
Hmmm.. I wonder if I could do any of this with
my OS9 system
running on a Tandy COCO? Lot's of ability to fudge with disk
formats and you can't find a controller much older. :-)
Makes me wonder about the other old TRS80's. All handle 5.25
floppies and have old controllers. And OSes that let you do
pretty much anything you want. Even shoot yourself in the foot.
I wonder if I even have any RX50 floppies laying still around
here anywhere?
Certainly!
The Coco used a Western Digital 179x controller. I don't remember which
specific one, and for simple stuff like this, it won't matter much.
The WD doesn't have the "flash blindness" that sometimes interferes with
the
NEC 765 series when reading disks where the first sector is too soon after
the index pulse.
The WD has a semi-raw track read that is real handy (The NEC has a multiple
sector read, but not a raw track read)
There have been some programs on the Coco for reading and writing some other
formats. ISTR Dr. Marty did one on the Coco for reading PC disks. (probably
published in Rainbow)
The TRS80 Model 3 and 4 also used 179x controllers. With very different
operating systems (The Randy Cook family of OS). Look for by
Mike Gingel, as a program running on TRS80.
Also, "Trakcess" is very handy for analyzing disks, although you need to do
some trivial mods to it for double sided, etc.
Looking at the program of Trakcess will make it easy to get the basics to do
almost anything that you want to do.
William Barden did a nice pamphlet on disk I/O for TRS80.
Then Harv (HC) Pennington wrote very extensively about the internals of
TRS-DOS.
Until August 1981, when the 5150 came out, my disk format conversion work was
on TRS80.
The TRS80 model 1 used the 1771 controller which was single density only.
And, the original SA400 single sided drive on it only got 35 tracks.
Be careful, the second side signal on the cable is used on the Model 1 as
drive select for the fourth drive! (Tandy wasn't planning on DS drives)
But, the retrofit "Doubler" added a 179x controller.
As a REAL programmer, you can shoot yourself in the foot with any language or
operating system! (Is that the definition of programmer?)
--
Grumpy Ol' Fred cisin at xenosoft.com