[Coco] HDB-DOS Eprom

[Tormod Volden]

On Fri, Mar 18, 2016 at 9:59 PM, Gene Heskett wrote:
> On Friday 18 March 2016 15:59:17 Tormod Volden wrote:
>> Out of curiosity, what is the origin of the $5A000 value?
>
> That is sector offset to the beginning of the HDBDOS/basic disks, and
> allows 94,371,840 megabytes for os9, which is about 3/4 of what can be
> handled with a cluster size of 1.  Above about 132 megs it needs a
> cluster size of 2, then 4 at just above 250 megs, moving up in powers of
> 2, so my 1Gb seagate I have as S1, is running with a cluster size of 16,
> or $10 in hexidecimal.  We run out of cluster size room at about 4Gb
> IIRC.

I know the maximal /sector/ number is 0xFFFFFF, so I can understand
different /sector/ sizes give different maximal capacities. But why
does the cluster size play a role? Is there a limit to the cluster
allocation bit map size?

Tormod