4 Dec
2002
4 Dec
'02
4:24 p.m.
Does anyone have any documentation on the data structures of TRSDOS 1.3?
Specifically, I'd like to know the catalog structure, as well as the
scheme for storing files across multiple sectors.
I'm trying to pull some old word processor and perhaps spreadsheet files
off some TRSDOS disks using a PC. I already found a utility called
READDISK that reads TRS-80 disks on a PC and it worked great. Now I need
to extract the files from the image.
Is this data published in any of the TRS-80 DOS manuals?
Sellam Ismail Vintage Computer Festival
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International Man of Intrigue and Danger http://www.vintage.org
* Old computing resources for business and academia at www.VintageTech.com *
4 Dec
4 Dec
4:54 p.m.
Sellam asks:
Does anyone have any documentation on the data
structures of TRSDOS 1.3?
Specifically, I'd like to know the catalog structure, as well as the
scheme for storing files across multiple sectors.
I think you want _TRS-80 Disk and Other Mysteries_. That was one of
the Mysteries books I didn't have, but ISTR that Al turned up a copy
recently.
Each track had 10 sectors. They were allocated to files in groups of
five, which were called granules or grans. There's a Granule Allocation
Table (GAT) which I think was basically an allocation bitmap.
In other DOSes for the TRS-80, which had support for higher-capacity
disks, the number of sectors per granule was often different.
Eric
7 p.m.
On Wed, 4 Dec 2002, Eric Smith wrote:
Sellam asks:
There are a few other books that DO give the info, including some from RS,
but Pennington's is the one you want (the equivalent of "Beneath Apple
DOS")
Does anyone have any documentation on the data
structures of TRSDOS 1.3?
Specifically, I'd like to know the catalog structure, as well as the
scheme for storing files across multiple sectors.
I think you want _TRS-80 Disk
and Other Mysteries_. That was one of
the Mysteries books I didn't have, but ISTR that Al turned up a copy
recently. Each track had 10 sectors. They were allocated to
files in groups of
five, which were called granules or grans. There's a Granule Allocation
Table (GAT) which I think was basically an allocation bitmap.
In other DOSes for the TRS-80, which had support for higher-capacity
disks, the number of sectors per granule was often different.
TRS-DOS 2.x (MODEL 1) was 10 sectors per track.
TRS-DOS 1.x (model 3) was 18 sectors per track.
5 Dec
5 Dec
1:13 a.m.
I have the Pennington book, Sellam. If you can't find a copy locally, I
might be able to scan the pertinent sections.
--Mike
Michael Nadeau
Editor/Publisher
Classic Tech, the Vintage Computing Resource
www.classictechpub.com
----- Original Message -----
From: "Eric Smith" <eric(a)brouhaha.com>
To: <cctalk(a)classiccmp.org>
Sent: Wednesday, December 04, 2002 10:51 PM
Subject: Re: Need information on TRSDOS 1.3 internals
Sellam asks:
Does anyone have any documentation on the data
structures of TRSDOS 1.3?
Specifically, I'd like to know the catalog structure, as well as the
scheme for storing files across multiple sectors.
I think you want _TRS-80 Disk and Other Mysteries_. That was one of
the Mysteries books I didn't have, but ISTR that Al turned up a copy
recently.
Each track had 10 sectors. They were allocated to files in groups of
five, which were called granules or grans. There's a Granule Allocation
Table (GAT) which I think was basically an allocation bitmap.
In other DOSes for the TRS-80, which had support for higher-capacity
disks, the number of sectors per granule was often different.
Eric
6:06 p.m.
On Thu, 5 Dec 2002, Michael Nadeau wrote:
I have the Pennington book, Sellam. If you can't
find a copy locally, I
might be able to scan the pertinent sections.
ABE turned up nothing so yes, I could use a scan. Unless Fred can find
and loan me his copy.
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
* Old computing resources for business and academia at www.VintageTech.com *
11 Dec
11 Dec
6:06 p.m.
On Thu, 5 Dec 2002, Sellam Ismail wrote:
I have located my copy of Pennington.
I also have a copy (from the same publishing series) of Farvour's "TRS-DOS
2.3 Decoded & other Mysteries", which has descriptions of the data
structures and code disassembly of the OS.
Of all of the folk who responded with recollections of what the [minor]
differences are between model 1 and model 3 TRS-DOS, I'd trust Tim Mann's
most. The rest of us are all working from flaky old memories; and if not
refreshed regularly, wetware RAM is not non-volatile.
If you do a dump of some of the directory sectors (256 bytes per sector,
track 17?), it won't be hard to work through them. TRS-DOS attempted to
implement some stuff that was really overkill for a micro OS (like the
H.I.T.), but finding and reading the files isn't hard.
I'm grading exam papers for the next few days, so you could come by my
house (call first), or come up to the college next Monday, Tuesday, or
Wednesday evening.
--
Grumpy Ol' Fred cisin(a)xenosoft.com
I have the
Pennington book, Sellam. If you can't find a copy locally, I
might be able to scan the pertinent sections.
ABE turned up nothing so yes, I
could use a scan. Unless Fred can find
and loan me his copy. 
5 Dec
5 Dec
1:17 p.m.
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6 Dec
6 Dec
1:56 a.m.
All these terms are waking up old memories (and brain cells) from my
youth...I used to do some low level programming as a kid on TRSDOS 1.3
in my parent's basement. Thanks for the pleasant memories.
-Chandra
-----Original Message-----
From: cctalk-admin(a)classiccmp.org [mailto:cctalk-admin@classiccmp.org]
On Behalf Of Tony Duell
Sent: Thursday, December 05, 2002 6:44 PM
To: cctalk(a)classiccmp.org
Subject: Re: Need information on TRSDOS 1.3 internals
Each track had 10 sectors. They were allocated to
files in groups of
five, which were called granules or grans. There's a Granule
Allocation
Table (GAT) which I think was basically an allocation
bitmap.
TRS-DOS 1.3 ran on the model 3 which used double density (MFM)
recording.
IIRC, there are 18 sectors per track, and 6 sectors per granule (I think
it's 6, not 9).
The GAT is much the same on all versions of TRS-DOS, as is the HIT (Hash
Index Table -- which relates a hashed form of a filename to the
directory
entry that contaisn the info for that file).
-tony
4 Dec
4 Dec
6:57 p.m.
On Wed, 4 Dec 2002, Sellam Ismail wrote:
Does anyone have any documentation on the data
structures of TRSDOS 1.3?
Specifically, I'd like to know the catalog structure, as well as the
scheme for storing files across multiple sectors.
I'm trying to pull some old word processor and perhaps spreadsheet files
off some TRSDOS disks using a PC. I already found a utility called
READDISK that reads TRS-80 disks on a PC and it worked great. Now I need
to extract the files from the image.
Is this data published in any of the TRS-80 DOS manuals?
The book that you need is "TRS-80 Disk and other Mysteries" by
H.C. Pennington.
My copy is inaccessible to me until Monday. (in my office at the college)
The program that you need is "Hypercross"? or "PCXZap"? by Mike
Gingel
("Hypersoft")
I'm giving final exams next week, so my schedule is a bit screwed up; If
you need help, I'll try to work it in.
--
Fred Cisin cisin(a)xenosoft.com
XenoSoft http://www.xenosoft.com
PO Box 1236 (510) 558-9366
Berkeley, CA 94701-1236
7895
days inactive
7902
days old
8 comments
6 participants
participants (6)
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ard＠p850ug1.demon.co.uk -
cbajpai＠attbi.com -
cisin＠xenosoft.com -
eric＠brouhaha.com -
foo＠siconic.com -
menadeau＠attbi.com