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From: woody@nntp-server.caltech.edu (William Edward Woody)
Newsgroups: comp.sys.mac.misc,comp.windows.ms
Subject: Re: give me solid facts: why is the mac better than MeSsy DOS/WINDOWS
Message-ID: <1991Mar30.084515.18789@nntp-server.caltech.edu>
Date: 30 Mar 91 08:45:15 GMT
References: <1991Mar26.063111.3133@cs.uoregon.edu> <1991Mar27.195719.15623@maths.tcd.ie> <10212@hub.ucsb.edu>
Organization: California Institute of Technology, Pasadena
Lines: 51

In article <10212@hub.ucsb.edu> doner@henri.UUCP (John Doner) writes:
>In article <1991Mar27.195719.15623@maths.tcd.ie> mike@maths.tcd.ie (MIKE ROGERS) writes:
>>	The Amiga just goes ahead and launches multiple copies. I saw this
>>happen with a user and ProPage2. She'd launched three copies of the program 
>>before I could stop her, each overlaying the other. Nice.
>
>Why would one want this functionality?  I use a Mac with Multifinder
>running, and I can have multiple copies of the same program running if
>I make duplicate copies of the program on the disk, using different
>names, and then starting each of them.  But so what?  

The reason why multiple instances of an application is desirable under
Microsoft Windows is that under Windows it's generally 'one instance --
one file'.  That is, if you have two text files to edit, you open two
copies of your text editor, one for the first edit file, and one for the
second.

On the Macintosh, applications are *supposed* to be able to open and edit
multiple files.  In other words, you need only one copy of your editor
to open several files at the same time.

The Windows model is easier to program.  After all, as each instance behaves
as if it is it's own private model, with it's own globals, you can be lazy
and stick the contents of your text file (or whatever) into a global
data structure and use it there.  But I find the windows model is a bit
awkward to use; after all, if you want to open three text files, you have
to open three instances, then find the text files...  I have not found
a fast and easy way around this, and I would love it if someone could
tell me a quick workaround.

The Macintosh model is harder to write programs for.  Not too much harder,
though, as you basically need to create a structure which stores all of
the 'globals' associated with each 'window', and access those structures
as messages are passed to your windows.  However, when I want to open a second
text file, I can either double click on the text file (as in Windows),
or I can simply select 'open' under the ever-present 'File' menu, and open
a second text file in my application.

With the Macintosh model there is no need, therefore, to be able to run
multiple instances of an application, when a single instance will do.
(And before letting me know about the applications out there on the Mac
which don't allow editing multiple files, please realize that there are
applications out for Windows which won't let you run multiple instances.)

					-- Bill

-- 
	William Edward Woody		   | Disclamer:
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