Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!usc!apple!apple.com!chewy
From: chewy@apple.com (Paul Snively)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Inter-Process Communication
Message-ID: <9596@goofy.Apple.COM>
Date: 6 Aug 90 20:47:13 GMT
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
Lines: 53
References:<1990Aug4.063810.14788@cs.uoregon.edu> <2286@polari.UUCP> <JMLN7T@cs.swarthmore.edu>

In article <JMLN7T@cs.swarthmore.edu> jackiw@cs.swarthmore.edu (Nick 
Jackiw) writes:
> .> There were several articles in MacTutor written by Frank Alviani and
> .> Paul Snively on implementing an IAC driver on the Mac. 
...
> The MacTutor stuff, which is excellent...

Thank you--I wish I could look back at that work and say the same thing! 
;-)

>... is probably more general than you
> need, if your suite of programs require only a rigidly specified 
communication
> protocol.

Huh?  The IPC driver in MacTutor doesn't deal with "protocol" at all; it 
just lets you poll to see if the data (which can be in any format you 
like; it's just a block of bytes) has changed since the last time you 
checked.  It's more like the Edition Manager than any of Apple's IAC 
protocols.

> Its worth reading anyway, if you're thinking of a driver-based IPC.

This I'll agree with, and I'll even go so far as to ask what other kind of 
IPC makes sense on the Macintosh?

> You may also want to consider doing it with Appletalk.  An oft-overlooked
> an oft-overlooked feature of Appletalk is that it works fine even if you
> aren't connected to a net: each program can request a socket on the same
> machine, and then communicate with others (also on that machine) through
> that socket.

Frank and I originally intended to rewrite the SAWS (Snively, Alviani, 
Welsh, Sheets) IPC driver in terms of AppleTalk precisely so that we would 
have a network-capable IPC system.  Your point is well taken.

> Neither of these schemes has System 7-IPC's advantage of having a nicely
> developed protocol for IPC between applications of which only one is
> currently running.

Unfortunately, neither does System 7.0's IAC suite; "store and forward" 
messages didn't make it in.  [sigh]

__________________________________________________________________________
                                Paul Snively
                      Macintosh Developer Technical Support
                             Apple Computer, Inc.

chewy@apple.com

Just because I work for Apple Computer, Inc. doesn't mean that I believe 
what they believe, or vice-versa.
__________________________________________________________________________