From: Jim Brain (brain_at_jbrain.com)
Date: 2008-04-14 19:14:25
Craig Taylor wrote:
> Just a random thought - use the 1571 u0>h1, u0>h0 commands to indicate which
> portion of the 512 block (eg : 0 = 0-255, 1 = 256-511) ... the organization
> won't strictly be from a "head" perspective but since we're dealing with
> hard-drives I don't think it should matter as much - just as long as the
> capability is there.
>
> As a further extension, u0>m1 could add an additional bam track for the
> second "side" that conditionally gets considered ....
>
I stil think 256 byte sectors are the most compatible (How do you
reference loading from the 257th byte of a sector using B-R or U*
commands?). Yes, you can ignore such things, but I think it's trivial
to handle 256 byte logical sectors in a 512 byte physical sector
environment. uIEC and sd2iec do it and it does not take lots of extra
RAM. 1581 did it as well.
But, I like Craig's idea in another context. Use u0>h* to move to
different virtual "heads" in the partition.
Say, for instance, that you decided to limit partitions to 16MB, as
that's 255T*256S*256bytes... You also have 254 partitions, so that
16MB*256 or 4GB. You could use u0>h1 to access a completely new set of
256 partitions as a different drive, using the same drive number.
I think there is a way to reference 255*256*256*256 bytes in a "disk",
so a partition could be 4GB. 254 partitions would be a very large disk,
but H1 could double it.
Jim
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