Re: system incompatibility

[reti@cambridge.apple.com (Kalman Reti)]

At  8:23 PM 11/29/94 -0600, montbrj@duke.usask.ca wrote:
>I'm curious about why mcl appears to be incompatible with different
>system versions and releases, hardware platforms across the macintosh
>line, etc..  my question is:  why is this happening?  I'm just curious,
>this isn't really a complaint, I'm just looking for tips about
>what toolbox calls, and strategies are making this happen so
>I can be aware of these issues...
>
>thanx in advance
>
>-john

The main reason for incompatibilities are the assumptions built into MCL
are violated when new hardware/software comes out, i.e. assumption of FPU
in 68040 was violated by 68LC040, the set of MMU types was extended by
the PowerMac, assumptions about the format of internal memory manager
data was violated by the new memory manager, etc.  MCL keeps its fingers
closer to the hardware and system software than most apps in order to
provide good performance for things like EGC, the downside of this is that
things change out from under you...

[One man's opinion]