Need information on TRSDOS 1.3 internals

From: Fred Cisin <cisin_at_xenosoft.com>
Date: Thu Dec 5 00:00:01 2002

On Wed, 4 Dec 2002, Eric Smith wrote:
> 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.

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")

> 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.
Received on Thu Dec 05 2002 - 00:00:01 GMT