[Coco] OS-9 sector allocation bitmap AKA LSN 1

Willi Kusche CoCo at wilserv.com
Sun Sep 2 18:43:26 EDT 2012


On Sun, Sep 2, 2012 at 6:17 PM, Gene wrote:
> The numbering system, at least in os9, is base 0. AFAIK, free reports the
> correct data, and it gets it from the map sectors.

    What I'm wondering is why, even in a disk that is only half full,
resulting in a string of null bytes in the bitmap, is the rightmost
bit of the last bitmap byte always set?  Normally, that last bit
shouldn't be set until the disk becomes completely full.  Since
posting my original query, I took a quick look at the source for the
"FORMAT" command but that's a huge chunk of source for a 6809 newbie
like me to make sense of.


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