Path: utzoo!attcan!uunet!husc6!ukma!rutgers!apple!mattd
From: mattd@Apple.COM (Matt Deatherage)
Newsgroups: comp.sys.apple
Subject: Re: UniDisk or SmartPort on a card?
Message-ID: <28208@apple.Apple.COM>
Date: 1 Apr 89 08:43:31 GMT
References: <1190@microsoft.UUCP>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 52

In article <1190@microsoft.UUCP> brianw@microsoft.UUCP (Brian Willoughby) writes:
>Why should I buy a UniDisk 3.5 for my II+, when all the new II's use the
>Apple 3.5 Drive? My local Apple dealer stated that he thought the UniDisk
>was only 400K like the original Mac.

Your local dealer is wrong; the UniDisk 3.5 is an 800K device.  We have code
in UniDisk 3.5 Tech Note #4 that lets you deal with 400K disks, though.

The reason the UniDisk doesn't work on IIe and II+ computers is really simple:
There's no interface card for it (from Apple).  The "UniDisk 3.5 Accessory Kit"
or something like that is the interface card for IIe and II+ computers, and
that card simply doesn't have the firmware (and maybe not the hardware)
to run the Apple 3.5 Drive, mainly since the card was released two years before
the drive was.

>What is the major difference between the UniDisk interface and the SmartPort? I

"SmartPort" usually refers to a firmware protocol developed by Apple to allow
Apple II peripherals and CPUs to get along better.  The term can also refer
to the actual, physical port on IIc and IIgs computers.  When talking about the
electrical signals generated by this port, we try to use the term "SmartPort
Bus" to avoid confusing people.  To use the firmware interface, you need to
know nothing about the hardware.

And as stated above, the difference between the UniDisk interface and the
SmartPort code in the IIgs and IIc Plus is that the UniDisk interface doesn't
know how to talk to Apple 3.5 Drives.

>If what I want (the Apple 3.5 Drive on a II+) is already possible, then please
>correct my misunderstanding. Otherwise, does anyone know which Apple
>documentation I could purchase that would allow the experienced (namely, me) to
>put together a SmartPort on a card that would function with the Apple 3.5 Drive
>and ProDOS 8 on a II+? Where can I learn about how the SmartPort interface
>works?

The best place to learn about this stuff is from the _Apple IIgs Firmware
Reference_ and the _Apple IIgs Hardware Reference_.  You'll also find quite
relevant information in the UniDisk 3.5 and SmartPort Technical Notes.

>Brian Willoughby                        microsoft!brianw@uunet.UU.NET
>                or                      uw-beaver!microsoft!brianw
>                or just                 microsoft!brianw

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