27 Sep
2014
27 Sep
'14
12:49 p.m.
On Sat, Sep 27, 2014 at 1:29 PM, Fred Cisin <cisin at xenosoft.com> wrote:
Job's "dream team" designing the Lisa
showed one example of when a high
level language is NOT an ideal solution. They clearly demonstrated many
examples where Theory and Reality don't match. Use of Pascal for writing
an OS betrays a lack of familiarity with hardware performance needs.
I don't think any of the Lisa's problems were due to use of Pascal.
The Pascal compiler used had extensions (similar to UCSD Pascal) to
handle things that were missing from the standard. If they'd run into any
other shortcomings in the language, they could have added more
extensions.
On the application side, they did exactly that, producing "Clascal", an
object-oriented extension of Pascal that was the precursor of "Object Pascal".
The Object Pascal language has been out of vogue for software development
on Macintosh computers for many years, but Borland added Object Pacal
to their Turbo Pascal compiler, and it's still used in the descendant, Delphi
(now from Embarcadero Technologies).
Significant components of the Lisa OS had to be
rewritten in assembly
language (or in some cases, maybe just C) to get acceptable performance.
The part that needed high performance and was rewritten in assembly was
Quickdraw, originally LisaGraf, and wouldn't have done any better in C or
any other HLL available for the 68000 at that time. This was more a matter
of quality of available compilers than any fundamental deficiency of HLLs.
If there were other parts of the Lisa OS written in assembly, I
haven't heard of it.