[Info-vax] Whither VMS?

[VAXman- at SendSpamHere.ORG]

In article <7irif8F31nq9iU12 at mid.individual.net>, Bob Eager <rde42 at spamcop.net> writes:
>On Sun, 04 Oct 2009 11:17:17 +0000, Bill Gunshannon wrote:
>
>>> Macro is an assembly language on steroids.  Bliss is an assembly
>>> language on steroids.  C needs Altoids, not steroids, because it
>>> stinks.  It doesn't even have a decent macro capability.
>> 
>> Because C came from the Unix environment and putting the Macro
>> Pre-preocessor in the compiler would have violated the paradigm Unix was
>> based on.  Thus, "cpp" and, of course, M4 as separate programs.
>
>It was also necessary for space reasons. The amount of address space 
>available on a PDP-11 with non-separate I/D space was only 64K. Of that, 
>8K (one page register) was set aside (AFAIR) for system communication, 
>leaving 56K for programs.
>
>c0 (the preprocessor) handled macros and includes. c1 was the compiler, 
>which generated dreadful code as there was no space for the code 
>generator to do optimisation. c2 was the optimiser, which did a lot of 
>clever stuff. I think c1 was the limiting factor, needing pretty well all 
>the available address space for program, and data structures.
>
>Just took a look - c1 was 15K, c1 was 21K, and c2 was 8K (approx). That's 
>just code and static data. c1 would need a lot of dynamically allocated 
>storage for symbol tables, parse trees, etc.

If you haven't taken notice, C isn't being used these days for PDP-11
programming.


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