Re: Using Mac 20 meg HD on A2 drive port???

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

Dave Althoff <dalloff@freenet.columbus.oh.us> wrote:

> How about this for an idea...
> 
> How about an IDE drive controller that can talk to the SmartPort?  My
> thought is to put an itty bitty hard drive (such as a Focus-type drive)
> into a //c. Sure, it would be slower than a 'proper' HD interface, but it
> would still be faster than the 5.25" floppy.

Not by much.  The bit time of the SmartPort protocol is 4 microseconds,
which is the same as a 5.25" drive.  The only benefit gained is that you
have a full 7-bit data path instead of a 6-bit encoded format, so you
save some CPU decoding overhead, and get an extra 17% throughput.

There are also the benefits of increased capacity and significantly
reduced seek times, of course.


By comparison, the Apple 3.5 Drive uses a 2 microsecond bit cell, which
means that it twice as fast as the UniDisk 3.5 or Disk ][ under ideal
circumstances.

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