Re: Low-level vs. High-level programming (was My First Computer)

[mjmahon@aol.com (Michael J. Mahon)]

Michael Pender wrote:

>John B. Matthews <nospam@nospam.com> wrote in message
>nospam-967967.21253716072003@clmboh1-nws3.columbus.rr.com">news:nospam-967967.21253716072003@clmboh1-nws3.columbus.rr.com...
>>
>> Logo was a delightful environment, but not the only "serious" recursive
>> stack machine in wide use on Apple II.
>>
>> Apple's UCSD Pascal implemented a very efficient stack machine. Each
>> stack frame had a static and dynamic link to allow recursion from an
>> arbitrary nesting level.
>
>Apple Pascal was a half-baked implementation of the language that offered
>very limited system access.  It was a compiled Fortran program that
>inherited all of the limitations of the Fortran language, as well as those
>of Pascal.

No.

UCSD Pascal was a microcomputer adaptation of Wirth's ETH Zurich
portable Pascal implementation (based on P-code).  In the process
of adapting it to microcomputers, the biggest problem was memory
space, so it is painfully optimized toward saving space at the clear
expense of a regular P-code.

Later, a FORTRAN implementation was done (in Pascal) which
used the same P-code interpreter as Pascal.

>For example, a program could not have more than 3 files open at once,
>system-wide.

Pascal certainly has many limitations as a system programming
language (many of which were conscious tradeoffs made to enhance
its educational value, in the eyes of its creator).  Limitations like the
number of simultaneously open files are not language limitations,
but implementation limitations--another consequence of optimizing
for very small memory (64KB) systems.

-michael

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