Re: Need Disk Format Info

[voss@i40s16.ira.uka.de (Stefan Voss)]

In article <cfiySe200WB71dRUVT@andrew.cmu.edu>, Christopher James Larson <cl2i+@andrew.cmu.edu> writes:
|> 
|> I need to find out some information about the format of a 5.25" disk on the
|> Apple IIe.
|> [stuff deleted]  
|> Track 11hex is the track that contains the catalog info, I think.  
|> I need to know how it assigns the program names to where they are located 
|> on the disk.  

Yes, you are right. Track $11 contains the catalog information, beginning at
sector $F and continuing towards sector $0. Each catalog entry contains:
- the file name
- the file type (BAS, BIN, TXT, ...)
- a pointer to the track-sector-list (TSL) (I believe, it's in SS TT order.
  i.e. SS is the sector number and TT is the track number.)
- ... (can't remember other things. Please also note that I'm unsure about
  the order of file name, file type and TSL.)

The TSL itself just consists of up to 128 SS-TT-pairs (pointers to the data
sectors). Because the TSL is just 1 sector, a DOS3.3 file is limited to
128*256 = 32768 bytes (= 32k).

For further information I recommend the book "Beneath Apple DOS" by Don Worth
and Pieter Lechner. If I find the time I'll take a look at it myself and email
you a more detailed description of the DOS3.3 catalog track.

That's it for now.

Stefan Voss
(voss@ira.uka.de)