4 Dec
2002
4 Dec
'02
9:54 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