Re: howto make system calls (newbie question)

[charleshixson@earthling.net (Charles Hixson)]

Kilgallen@eisner.decus.org.nospam (Larry Kilgallen) wrote in
<2ecbjJt$+0y8@eisner.encompasserve.org>: 

>In article <9dauu7$8m913@news.kvaerner.com>, "Tarjei T.
>Jensen" <tarjei.jensen@kvaerner.com> writes: 
>...
>I certainly agree, but I was responding to a thread with
>entries espousing codification of all "standard datatypes"
>that might be used in system calls.  I consider that
>unworkable, because what constitutes a "standard datatype"
>varies so much between various operating systems.  
>Basically, I do not feel there is progress to be made in that
>direction. 
>
Perhaps the problem is the correct level of abstraction.  
Clearly machine/OS specific variations don't belong in the 
standard, but I also feel that SOME way of accomplishing the 
needed tasks does belong in the standard.  It may be that on 
some machines this would be inappropriately inefficient, but at 
least it would be possible.  This is somewhat similar to using a 
numeric 1 to indicate true.  If your machine has a 60 bit word 
length, then this may be quite inefficient.  But it will make 
the transmission of logical information possible.  (I believe 
that this was, indeed, the way that it was done on the CDC7600, 
at least in the Fortran that I used.)

As with the representation of Booleans, so with other things, it 
is frequently true that a less efficient method will be "good 
enough", and that portability will pay back for numerous 
inefficiencies.  And a good compiler could come with specialized 
libraries that would handle the process in a way more 
appropriate to the particular machine/OS.  (On the 7600, it was 
a speed trade off.  The individual bits couldn't be addressed, 
so for speed the >0 comparison was used [I believe that other 
compilers just checked the sign bit]).

-- 
Charles Hixson

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