Re: Apple II Csa2 FAQs 9/9/1998 Zip Drive & Tape

[dempson@actrix.gen.nz (David Empson)]

Supertimer <supertimer@aol.com> wrote:

> stever@gate.net (Steve Reeves) wrote:
> 
> >Supertimer wrote:
> >>Rubywand, I don't know if you have tried this, but if I DON'T
> >>partition a Zip disk but instead simply format it from Finder
> >>using HFS on the GS, the volume seems a bit faster than
> >>if I partition it and use HFS.  I don't know why this is so.
> >
> >Obviously part of the reason must be that the driver can skip the
> >logical-to-physical block address translation.  I doubt that this
> >by itself would create a noticeable difference in performance,
> >though, except maybe on an unaccelerated GS.

I find that hard to believe.  That is a simple lookup and add operation
for each data access (read or write call from the application or FST).
On an unaccelerated IIgs, I would be surprised if it took as much as 50
microseconds, and the computer wouldn't be doing a huge number of these
per second (unless the driver is badly written).  This time is swamped
by the overhead of the SCSI command execution and data transfer.

The only other thought that occurs to me would be double checking of
range limits - making sure the data access doesn't exceed the size of
the partition, then rechecking against the size of the drive.  There
wouldn't be much point doing that, though.

Nothing else occurs to me as a feasible explanation.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand