Re: Will Apple Disk ][ wo

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

In article <25MAR199509501959@vax2.concordia.ca>,
Mitchell Spector <spector@vax2.concordia.ca> wrote:
>
> 	Doesn't the Apple 5.25 (platinum) have a slightly higher transfer
> rate or access time than the original Disk ][?

Transfer rate: all Apple II 5.25" drives are exactly the same.  The
controller cards are the same, and the timing is all controlled by the
IWM (or logic state sequencer).  The bit time is fixed at 4
microseconds (roughly).

Access time: doubtful.  The seek time is controlled by software.  If
they changed the settling time, copy protection schemes such as
quarter-tracking would fail.

> I recall seeing a side-by-side speed comparison in Nibble magazine.

Are you sure it wasn't comparing 3.5" and 5.25" drives?  The 3.5"
drive transfers data twice as fast as the 5.25", and seek times are
definitely faster.

> And perhaps it's my imagination, but the Apple 5.25 (or
> DuoDisk/UniDisk 5.25) seems a bit faster when reading or writing to
> floppies than my Disk ][ units.

With the same operating system in each case?  ProDOS is faster than
standard DOS 3.3.

> 	Just wondering if the Apple 5.25 has any advantage over the
> Disk ][ besides better looks and a more standard interface. :)

The spring-loaded eject mechanism and the lower height.  It also has
an optical write-protect sensor instead of a microswitch.
--
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand