Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!usc!apple!apple.com!chewy
From: chewy@apple.com (Paul Snively)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Tail patches
Message-ID: <5293@internal.Apple.COM>
Date: 20 Nov 89 17:47:00 GMT
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
Lines: 92
References:<5249@internal.Apple.COM> <17090@dartvax.Dartmouth.EDU> <17105@dartvax.Dartmouth.EDU>

In article <17105@dartvax.Dartmouth.EDU> earleh@eleazar.dartmouth.edu 
(Earle R. Horton) writes:
> "Assembly-language note:  Changing the value of the block's master
> pointer lock bit with a BSET instruction is faster than HLock.
> However, HLock may eventually perform additional tasks."

The last sentence says it all.  We've ALWAYS recommended AGAINST direct 
manipulation of data structures.

In article <17105@dartvax.Dartmouth.EDU> earleh@eleazar.dartmouth.edu 
(Earle R. Horton) writes:
> immed           EQU $200         ; execute immediately, bypass I/O queue

It's redundant; all I/O calls execute synchronously unless they are 
specified async.

In article <17105@dartvax.Dartmouth.EDU> earleh@eleazar.dartmouth.edu 
(Earle R. Horton) writes:
> ;The following twelve OS traps have been redundantly defined as
> ;Tool traps as well. They should be
> ;accessed as OS traps, but their slots in the Tool trap table
> ;will be reserved forever.
> ;       $1A GetZone
> ;       ...

What broke here?

In article <17105@dartvax.Dartmouth.EDU> earleh@eleazar.dartmouth.edu 
(Earle R. Horton) writes:
> "Assembly-language note:  To get a pointer to the end of RAM from
> assembly language, use the global variable MemTop."

For virtually all purposes, this is still true, although it really 
shouldn't be necessary to ask where the end of physical RAM is in the 
first place, and there'd better be a better way than a low-RAM global to 
get what you want (for example, we now are facing virtual memory, etc.  We 
are providing ways to get various kinds of memory information in a cleaner 
way).

In article <17105@dartvax.Dartmouth.EDU> earleh@eleazar.dartmouth.edu 
(Earle R. Horton) writes:
> Network Events.

Ah, a good one.  There WAS a fair amount of code that died due to this.  I 
think this one falls into the category in your last two sentences: it was 
a bad idea in the first place, but it was OUR idea.

In article <17105@dartvax.Dartmouth.EDU> earleh@eleazar.dartmouth.edu 
(Earle R. Horton) writes:
> Calling PopupMenuSelect under System 6.0 with Color QuickDraw caused
> the menuWidth and menuHeight both to be set to -1!  I was told that
> this was done deliberately to allow for the possibility of a loaded
> menu being used on different monitors.  Result: CalcMenuSize is broken
> under System 6.0 because its effect is not what IM says it is.

This sounds pretty brain-dead to me too; I'm completely unaware of this.  
I'll ask other DTSers about the whys and wherefores.

In article <17105@dartvax.Dartmouth.EDU> earleh@eleazar.dartmouth.edu 
(Earle R. Horton) writes:
> Tags.

This may have affected some disk utility types, but it actually made life 
easier for hard disk folks, since we no longer had such screwy sector 
sizes.

In article <17105@dartvax.Dartmouth.EDU> earleh@eleazar.dartmouth.edu 
(Earle R. Horton) writes:
> Mac Plus keyboard shifted arrow keys return identical codes to numeric
> keypad keys.  This hardware was shipped in a broken state, and no fix
> was ever supplied.  Weak-ass excuse supplied by Apple was that this
> was done for compatibility with original separate numeric keypad.

Just because YOU THINK it's a weak-ass excuse doesn't mean that it IS one; 
being incompatible with our (very popular) separate numeric keypad would 
have been unacceptable to our users and our developers.

In article <17105@dartvax.Dartmouth.EDU> earleh@eleazar.dartmouth.edu 
(Earle R. Horton) writes:
>   "We broke it because it was a bad idea in the first place, anyway."
> 
>   "Fine, but remember, it was YOUR idea."

This is probably the most common case, and in many of THOSE cases, I'd say 
it's the documentation that is broken and not the software or hardware.

__________________________________________________________________________
Just because I work for Apple Computer, Inc. doesn't mean that they 
believe what I believe or vice-versa.
__________________________________________________________________________
C++ -- The language in which only friends can access your private members.
__________________________________________________________________________