Path: utzoo!yunexus!unicus!craig
From: craig@unicus.UUCP (Craig D. Hubley)
Newsgroups: comp.sys.amiga
Subject: AppleTalk/LocalTalk and Amigas
Keywords: Device Drivers, Networks, AppleTalk
Message-ID: <2412@unicus.UUCP>
Date: 22 Mar 88 06:16:27 GMT
Article-I.D.: unicus.2412
Posted: Tue Mar 22 01:16:27 1988
Reply-To: craig@unicus.UUCP (Craig D. Hubley)
Organization: Unicus Software Inc., Toronto, Ont.
Lines: 70


Mark Gooderum asked me to post this for him, since his Pnews is misbehaving:
------------------------------------------------------------------------
I have gotten several messages about Apple Talk and it looks like it isn't
as easy as I thought.  Would you please forward this to Comp-Sys-Amiga (I
had to go throught HUGE contortions to post my message)?

Thank you very much for the replies I have received on AppleTalk.  I have
found out that some of my original assumptions were wrong but here is what
I found.

1.) Hardware-AppleTalk uses RS422 **synchronus** hardware protocol.  Inside the
        Mac there is a special chip (by Zilog) that handles things like
        reconstructing the clock rate.  The other problem is AppleTalk
        runs at 254K baud.  The Amiga's serial port is FAST but not that
        fast.  The best I have heard on the Amiga is about 160K baud and
        that required taking over the machine.  In the normal multitasking
        environment 60K baud seems the limit.  So the hardware interface
        looks like it would require a special port on a board that goes
        directly on the bus.

2.) Software-Handleing the packets on AppleTalk is an unsure idea.  I have
        heard everything from easy to hard.  One person told me that
        the UNIX version of AppleTalk was 10000+ lines of code.  Another
        person said that as long as you had a 'real' Rs 422 port to
        handle the hardware part of the protocol the code was easy (like
        the IBM AppleTalk card.)

Also there was some confusion as to terminology as to AppleTalk -vs-
'Local Talk'.  Originally AppleTalk was AppleTalk.  Then as Apple started
to get into connectivity with VAXes and Ethernet, the scope of AppleTalk
expanded significantly.  Also there were many complaints about the original
AppleTalk connectors coming loose because they didn't lock.  So Apple
came out with new locking connectors.  The new connectors are called
the "LocalTalk Cabling System".  "AppleTalk" now refers to the whole
overall system (mainly the protocols) while "LocalTalk" refers to the
physical boxes and cables sold.

Finally, it looks like a bigger deal than I orininally thought.  Several
people suggested I contact Apple and the Apple Developer's Association.  I
will do this.  My orininal motivation was a low cost networking solution
for the Amiga especailly one that would allow easy access to PCs and Macs.
I still think this could be done for LOTS less than Ethernet.  Someone
said if I cold sell AppleTalk for the Amiga for under $150 I could get
rich.  I probably could but the whole of this project is too big for just
me.   So there are a few solutions.

1.)     Give up.  (Too easy.)

2.)     Pair up with some people and attack the problem as a group.  This
        might work if there are interested people out there.  If you are
        interested let me know.  I am okay and getting better on programming.
        (Actually I am a good programmer, just a relatively new serious
        Amiga programmer.)  The group would definitely require a hardware
        hacker and preferablly an expirience Mac person.

3.)     Wait for someone else to do it.

4.)     Persuade Apple to do it.  Yes, this is a possibility.  They put
        it out for the IBM and they are trying hard to get AppleTalk
        accepted as the 'new' office network.

5.)     Try something simpler.  Maybe a SCSI based network.  Small but cheap.
        The main problem is the difference in SCSI drivers.

Well, there is my too many cents worth.

-Mark Gooderum
 University of Kansas
 MARKV@UKANVAX.BITNET