From: zmonster@athena.mit.edu (Eric M Hermanson)
Subject: Re: Mac multitasking?
Organization: Massachusetts Institute of Technology
Distribution: na
Date: Sat, 12 Dec 1992 08:27:58 GMT

In article <Bz4Fqx.Isy@javelin.sim.es.com> mmunson@animal.es.com (Mark Munson) writes:

>MM> OK, let's say that you upgraded your OS to handle 8-channel sound sequences
>MM> and MIDI data.  Would your current spreadsheet, wordprocessor, and database
>MM> applications be able to take full advantage of the upgrade?  Or would each
>MM> need to be modified to deal with improvements outside of their intended scope?
>MM>
>MM> Just wondering what you think?
>MM>
>MM> [MGM]
>
>
>EH> Well, I am not sure why you want your word processor to handle MIDI data, but
>EH> in any event, with NeXT, MIDI is fully supported by the operating system, 
>    ^^^^^^^^^^^^
>Side stepping the question again ;)
>
>Your original argument was that Mac applications had to be rewritten to take
>advantage of new system features, and that NeXT computers didn't suffer from
>this due to it's object oriented structure.  But what you just told me was that
>you would have to upgrade or get new software to take advantage of new
>modules, although replacing or upgrading a currently used module would
>not require this.
>
>This is exactly how the Mac works.  If I want new or upgraded features I can
>just drop them (extensions) into the system.

I did not mean to side step the question.  Here is the answer:

YES, hypothetically, if the NeXT OS was upgraded to handle MIDI (it already
does handle this) then ALL programs would benefit form the upgrade, even
word processors that have nothing to do with MIDI.  Here is how it works:

ALL NeXT applications have a menu item called "Services".  Inside of the
services menu is a listing of applications that the existing application
can "talk to" or send messages to.  When you RUN an application, objects
are read in AT RUN TIME to the services menu, and your word processor would
be able to take input from the MIDI program, even though the word processor
was never written to do so.  Think of the Services menu as a blank menu
that is filled in with updated objects when the particular application is 
run.

This may be confusing, so let me give you a really concrete example.  I have
Word Perfect for NeXT.  When I run Word Perfect, the services menu gets
created at run time.  The menu gets filled in with objects from different
applications that Word Perfect may communicate with.  The other applications
have no relation to Word Perfect, nonetheless, Word Perfect can communicate
with them.  So, getting back to the example.  If I have some numerical data
in my Word Perfect file that I want to graph, I simply highlight that data,
go to the services menu, and choose "plot".  A message gets sent to the 
plotting package to plot the data that is highlighted.  As in the previous
paragraph, I could have sent the data to a MIDI program just as easily, even
though the MIDI program was written by an entirely differnet company with
no relation to Word Perfect.

To answer your question again,in brief form, YES, All applications benefit
 from upgrades,
even though the upgrades may be "beyond the program's intended scope", as
you put it.  If the OS was upgraded to handle MIDI, then all applications
benefit from this upgrade via the "Services" object menu item.

Eric 

Newsgroups: comp.sys.mac.advocacy