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From: AWCTTYPA@UIAMVS.BITNET (DAVE LYONS)
Newsgroups: comp.sys.apple
Subject: Mail from Participate at the University of Iowa
Message-ID: <8710201305.aa15914@SMOKE.BRL.ARPA>
Date: Tue, 20-Oct-87 20:39:24 EDT
Article-I.D.: SMOKE.8710201305.aa15914
Posted: Tue Oct 20 20:39:24 1987
Date-Received: Thu, 22-Oct-87 03:59:52 EDT
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Bill Dixon (& others)--

Some Finder details Keith Rollin didn't mention.  The Finder reads Icon files
from the ICONS directories on all disks that have them.  All files in these
directories (with the right filetype--$C9 or $CA, I don't remember which) are
read in when you enter the Finder.  The files contain Icons, rules for deciding
when to use the icons, and pathnames for applications that should be launched
when each icon is double-clicked on.

The Finder can match icons with files by three things:  Filename, Filetype, and
Auxiliary type.  A convention as useful as the Mac's has yet to be
established--if one or more "generic" ProDOS 16 filetype(s) was/were assigned,
then the Auxtype could specify 1 of 65536 different applications.  Someone
would need to assign id's to avoid conflicts.

There will be, in the future, at least one product for editing icons (and
specifying the matching rules and application pathnames).  New applications
will include icon files which can simply be copied into the ICONS directory of
the disk the application is on.

Existing applications will need to be revised before they will "care" that the
Finder is asking them to open/print files.
The procedure is to check the MessageCenter for a msg of type 0, giving a list
of pathnames and an Open/Print flag.   (See the release notes for System Disk
3.1.)