Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!wuarchive!zaphod.mps.ohio-state.edu!sdd.hp.com!decwrl!apple!apple.com!chewy
From: chewy@apple.com (Paul Snively)
Newsgroups: comp.sys.mac.programmer
Subject: Re: More Help with ScrnBase, Please
Message-ID: <9954@goofy.Apple.COM>
Date: 28 Aug 90 17:22:35 GMT
References: <1990Aug27.170838.199@murdoch.acc.Virginia.EDU>
Sender: usenet@Apple.COM
Distribution: usa
Organization: Apple Computer, Inc.
Lines: 85

In article <1990Aug27.170838.199@murdoch.acc.Virginia.EDU> 
mil@mendel.acc.Virginia.EDU (Maria I. Lasaga) writes:

[Code intended to help in using the alternate screen buffer deleted]

> Any help would be greatly appreciated.  I am very frustrated with this 
> problem.  I don't get why Apple doesn't put out a tech note on how to
> use the alternate video buffer on the "lower" macs.

That's easy.  The Tech Notes are basically concerned with correcting 
errors in Inside Macintosh, with documenting new features as they come out 
(rather than waiting for a new Inside Macintosh), and for addressing 
misunderstandings, especially when they lead to software incompatibilities 
across the various machines/system software combinations.

Since the primary application of the alternate screen buffer is for games, 
it just hasn't gotten that high a priority for us, even though it is 
definitely a source of confusion and compatibility problems (for example, 
you can't just point the screen to the alternate screen buffer; you also 
have to set a bit on the VIA).

However, the alternate screen buffer, along with code to utilize it, is 
presented very well in one of MacTutor Magazine's anthologies of back 
issues.  The article is by Mike Morton, and I highly recommend it.

> Granted, the Mac II's 
> don't have an alternate buffer, but not everyone is into software 
development  
> for use on all machines.

Very true, but our job is basically to support Apple Partners who, for the 
most part, _do_ do development for use on all Macintoshes.  Of course, the 
academic environment (among others) is different, and we're trying to find 
ways to effectively address that.  (There are only about 35 or so of us 
and about 7,000-8,000 partners.)

> Besides, there is a lot of software available
> that doesn't run on the earlier macs.

How much is "a lot?"  And how much of this is just taking advantage of 
(necessary) new features, i.e. natural evolution?  We're essentially 
opposed to the development of software that doesn't work across machines 
for gratuitious reasons (note that this is a statement of personal 
opinion; your milage may vary).

> Why not allow us to develop some
> software that doesn't run on the Mac II?

No one is stopping you; rather, by pointing you to a source of the 
information, I am trying to help you.  However, I must admit that I find 
your railing about _us_ not being the source of the information vexing.

> I myself purchased an SE because it 
> had an alternate slot to which I could attach an external monitor, and 
> because it had an alternate video buffer.  I need to use these two 
options 
> for research purposes.  Yet I can't find documentation anywhere that 
tells 
> me how to take advantage of either of these two options!!

It's true that the sum total of information about Macintosh programming is 
scattered all over.  We're working on ways to consolidate it.  The 
Developer CD is a good example--IM I-V, the Tech Notes, sample code, etc. 
all in one place.  It's worth the price of the CD-ROM drive, in my opinion.

> -------------------------------------------------------------------------
-
> Maria Lasaga
> Dept. of Psychology
> Gilmer Hall
> University of Virginia
> Charlottesville, Virginia 22903                  mil@virginia.bitnet
> -------------------------------------------------------------------------
-

__________________________________________________________________________
                                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.
__________________________________________________________________________