Re: firmware for the PseudoDisk

["Alex Freed" <alexf@mirrow.com>]

<bieling@terra.es> wrote in message
1163357482.358273.285660@b28g2000cwb.googlegroups.com">news:1163357482.358273.285660@b28g2000cwb.googlegroups.com...
> > Alex Freed wrote:
> >
-cut-
> Is that, more or less, the way it is ?

I didn't check the details, but generaly sounds right.

>
> If that was correct, then:
>
> You could use the "borrowed" memory for caching the clusters' relevant
> data as it is found by the above process. I mean, start with an empty
> (filled with zeroes) table, and go filling it up as the need for a
> search (by the above, long process) arises. I mean, always check the
> table first, then if you find a 0 in the table you need to do the
> search, but starting from the last position filled in the table.
>
> There's no need to build a (big) complete translation table: it will
> also speed things up quite a lot if you just keep the relevant data of
> certain offsets within the file : for example, at offsets 0, 1/4, 2/4,
> 3/4 of the file size, so that you can start the search from the closer
> known offset, instead of from the begginning of the file. This way more
> than one table may easily fit in just one "borrowed" SDBlock.

I guess this is possible, but requires much more software than I want to
write myself. Maybe you want to do it?

Also keep in mind that when a ProDOS image is put on a blank SD card,
it will NOT be fragmented at all. And no matter how often you re-write
the files inside the ProDOS image, the image itself stays fixed on the card.


>
> Regards,
> Jorge Chamorro.
>