[Coco] Another Coco Virtual Disk Util

[Theodore (Alex) Evans]

On 10/21/2013 07:10 PM, Gene Heskett wrote:

> Name confusion Alex, os9 has been calling that disk area from LSN1 to
> LSN$100 (max, or however many it takes) the FAT since its first release.
> The address of the / directory in LSN0 is for its FD sector to start in the
> next sector after the FAT, and the directory itself is the next 7 sectors
> in sequence.

I have never seen any actual OS-9 documentation that referes to that
area as a FAT.  The Level 2 documentation calls it a disk allocation
map and I haven't looked at my level 1 documentation, but I believe
that it calls it the same thing.  It doesn't even serve the same
function as a FAT.  It merely indicated what ckusters are and are not
allocated.  A FAT is a singly linked list of allocated regions for
each file.  If you have a FAT the directory entry points to the first
allocated region. Each entry ina FAT indicated one of three things,
the region is unallocated, wht the next region in the file is, or that
the region is the last allocated region in the file.  As it happens
(not surprisingly considering that RS-DOS was developed by MS) this is
exactally the way the track 17 on an RS-DOS disk is layed out.

-- 
Theodore (Alex) Evans