Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!samsung!umich!sharkey!cfctech!ttardis!rlw
From: rlw@ttardis.UUCP (Ron Wilson)
Newsgroups: comp.sys.apple2
Subject: Re: AE 1.6 MB 3.5" drive
Message-ID: <2657@ttardis.UUCP>
Date: 29 Nov 90 20:48:11 GMT
Organization: Gallifrey
Lines: 43

In article <1990Nov18.060307.7413@eng.umd.edu>, russotto@eng.umd.edu (Matthew T. Russotto) writes:
>In article <13938@crdgw1.crd.ge.com> rankins@argentina.crd.ge.com (raymond r rankins) writes:
>>Does anyone have an info on the new 1.6MB 3.5 in disk drive from
>>Applied Engineering?  Mostly I'm interested in how they did it.  I
>>thought it wasn't possible to hook a high density drive to the GS
>>port, something to do with the SmartPort interface chip (or we would
>>have been able to put Mac 1.44 MB drives on it)?  Did they do it with
>>hardware hacking or a new 3.5 driver?  How compatible is it?
>
>Maybe they made the SmartPort think it was a REALLY SMALL Profile.
>Clearly, the drive must be 'smarter' than an Apple FDHD, which expects to
>see low level info (motor on/off, phase 0,1,2,3,4,??? on/off, read, write)
>from the disk controller.

Apple sells 2 3.5 inch floppy dirves that work on the IIgs SmartPort:

      The Apple 3.5, which is a "dumb" disk drive just like Disk ][

      The Apple Unidisk 3.5, which has an onboard CPU and talks to the
      IIgs (or Mac or other II with a SmartPort card) using the SmartPort
      protocol.

There are also a few 3rd party hard disk drives that also use the SmartPort
protocol.

Because the Smartport protocol is a serial protocol, data transfers are slow.
Interestingly enough, the dumb Apple 3.5 drive is actually faster than any
of the disk drives using the Smartport protocol (data transfer-wise, obviously
HDs have faster seek times).

Therefore it's entirely possible for a "smart" disk drive to support any
size and/or density disk on the "stock" IIgs Smartport.


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