[Coco] Re: Re: Re: Disk Basic and 512 byte block floppies.

Theodore Evans (Alex) alxevans at concentric.net
Thu Jan 22 22:04:00 EST 2004


On Jan 22, 2004, at 3:37 PM, Brett K. Heath wrote:

> I'm still going from memory here but I don't think so Mike. There may 
> have
> been a variant that used a linked list somewhere but in general the CPM
> directory was preallocated at a fixed size and location. Entries also 
> were
> of fixed and uniform size and consisted of a 32 byte field containing 
> name
> and file info followed by a 32 byte field of allocation block numbers. 
> If
> a file grew beyond what could be allocated within one entry then an
> additional entry for that file would be created wherever there was 
> space
> in the directory. Entries were not linked, the OS had to read the 
> entire
> directory, pick out those pertaining to the file of interest, and then
> order them according to the sequence numbers stored in the entries (not
> unlike the way TCP reconstructs files).


The file name and attributes field was only 16 bytes long, 11 of which 
are the file name.




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