Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!apple!goldman
From: goldman@Apple.COM (Phil Goldman)
Newsgroups: comp.sys.mac
Subject: Re: multitasking and IPC
Message-ID: <329@internal.Apple.COM>
Date: 18 Dec 88 20:53:52 GMT
References: <1988Dec16.191309.21623@cs.rochester.edu> <326@internal.Apple.COM> <264@berlin.acss.umn.edu>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 80

In article <264@berlin.acss.umn.edu> sec@berlin.acss.umn.edu (Stephen E. Collins) writes:
>In article <326@internal.Apple.COM>, goldman@Apple.COM (Phil Goldman) writes:
>> In article <1988Dec16.191309.21623@cs.rochester.edu> miller@ACORN.CS.ROCHESTER.EDU writes:
>> >    In article <1988Dec14.223739.16280@cs.rochester.edu> @DOUGHNUT.CS.ROCHESTER.EDU:miller@CS.ROCHESTER.EDU writes:
>> The only reason you cannot switch out of the Finder during file copy is
>> that the Finder runs in such a small partition that it swaps out its event
>> handling segment during the copy and thus cannot be switched. 
>
>Is that a bug or a feature?
>

A tradeoff.

>> > o I've also noticed that tasks that put up dialog boxes also inhibit my
>> >switching tasks from multifinder. Lose, lose. This may be a side effect of
>> 
>> No.  This is *strictly* a user interface decision.  Modal dialogs are put
>> up by the application when it demands the users attention.  Therefore,
>> it does not make sense to allow the user to switch, just as he cannot
>> do anything else to the machine except respond to the modal dialog.  If
>> the app's need is not that pressing it should put up a modeless dialog, or
>> use the notification manager.  The point is, that it *is* the application
>> writer's decision, not the OS's.  The OS provides the mechanism only, not
>> the policy.
>
>If this is the case, then any application that might ever be run under
>Multifinder should never make use of a Modal Dialog (so just burn 'em
^^^^^^^^^^^^MultiFinder
>out of the ROMS).  While an application may frequently require the
>user's attention before IT can continue, the system, in a MF environment,
>should ALWAYS be able to continue without requiring the user to
>attend to ANY individual application, no matter what state that
>application may be in.  You are still thinking in terms of single-tasking.
> 

No.  This is a user interface decision.  I understand your argument, but it
does not come down to a single- vs. multitasking decision.  Rather, it is
a decision on how much power to give to the application.

Also, remember that compatibility includes user interface compatibility as well.

>> I think that everything you say has merit in most computing environments.
>> However, the Mac w/ MF is an entirely different beast.  It has two very large
>> differences from other systems:  it must remain compatible with software
>> (including the ROM!) designed for a single-tasking machine, and it is driven
>> by a user interface designed for hiding the innards of the machine
>> completely beneath the desktop metaphor.
>
>I've been working on computers for some 15 years, and I can't think of
>a single system (nor application, for that matter) that didn't have
>the problem of remaining compatible with previous versions; and that
>includes many single-tasking vs multitasking evolutions.
> 

True.  Sorry for the hyperbole.  However, there are *few* systems with such
a large and demanding need for compatibility, caused by the combination of
a huge existing application base along with a very rich and complex application
model.  I'm sure someone more knowledgeable in the field can name a few with
both requirements.  I can't.

>Furthermore, the Mac user interface is not "entirely different".
>(ever hear of a company called Xerox?).  SUN, HP, and Microsoft
>come to mind immediately; I'm sure there are others.
>

Again, it is the combination of the two that makes the Mac w/MF unique, not
merely the user interface.

>The problems faced in the evolution of the Mac are not unique to the
>world of computing.  Those at Apple may like to think they are going
>where no man has gone before, but they would do well to examine and
>learn from the experiences of others.

Like any other computer maker, some of Apple's problems are uniqe, and
some are not.  I at least  would like to think that we do learn from other's
experiences, as well as from our own.  On that last note, much of the MF
interface could be seen many years ago on the Lisa.

-Phil Goldman
Apple Computer