Mac pointers and handles. Was: Chips that changed the world

[Ethan Dicks]

On Mon, May 4, 2009 at 7:18 AM, Roger Holmes
<roger.holmes at microspot.co.uk> wrote:
>> From: Ethan Dicks <ethan.dicks at gmail.com>
>> Subject: Re: Chips that changed the world
>
>>> Then of course there were those programmers that thought they were
>>> clever, using the top 8 bits to store flags in pointers, etc. ?Royally
>>> messed up when upgrading to 68020 and up.
>>
>> I remember reading a warning against such practices the original Mac
>> system manuals (the "hernia manuals"), but faced with 128K of RAM,
>> early programmers did not universally heed the warning.
>
> As I remember it, the warning was there because Apple had already used the
> top eight bits of pointers to hold flags for locked, resource, purge-able
> etc and if you wrote over them the OS crashed or made your application crash
> when it overwrote your flags.

Ah.  That could be.  I never did get into Mac development (I went into
embedded 68K programming, then later, Amiga programming for my 68K
experience).

> Incidentally, you refer to the "hernia manuals". Do you mean the ring bounds
> ones?

Yes. The ones in the 3-ring binders.  At one games house (Software
Productions), one of the guys bought his own original Mac and left it
at work when he was on vacation.  The boss was interested enough in
expanding to the Mac market that I think he bought the developer
manuals.  They stayed at work, at least, and I would browse them while
waiting for my C-64 code to compile on 1541 drives or to print on the
Diablo 1620 Daisywheel printer.

I think they were only called "hernia manuals" because they were
larger than, say, the Apple II docs.  By the time all the Amiga system
docs were published, there was at least twice as much paper, but
people didn't raise a whit of a fuss - we were used to phonebook-sized
system manuals.

-ethan