Interprocess Communication / Multitasking

[Warren Tucker]

In article <mark.666469192 at typhoon.ucar.edu> bradfrd2 at ncar.ucar.edu (Mark Bradford) writes:
>
>Here's the project: a real time data ingestion and archival system,
>built from several multitasking and cooperating programs using
>They say that UNIX is "notoriously lacking" in the necessary
>constructs to do this multitasking

UNIX lacks "lightweight processes," threads which execute within
a single address space (alas), but System V has all of the
necessary mechanisms for classical coprocessing (shared memory,
messaging, semaphores), so on the Sun you are in luck.  BSD has a
(usually unimplemented) mmap call which can support shared
memory, but lacks the other formal mechanisms you need (there are
hacks, but they are hacks).

You probably heard of "lacking" in reference to BSD.  System V
IPC has a bad name, but only among those have little experience
with the concepts involved or who have `enjoyed' exposure to it
on broken implementations.  The only pseudoproblem I have ever
had with it is key selection algorithms.  With a 32-bit key
`space', key management is problematical, but usually practicable.
 
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Warren Tucker, TuckerWare   gatech!n4hgf!wht or wht at n4hgf.Mt-Park.GA.US
Many [Nobel physics] prizes  have been given  to people for  telling us
the universe is not as simple as we thought it was. -Stephen Hawking in
A Brief History of Time     In computing, there are no such prizes. -me
-- 
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Warren Tucker, Tridom Corporation, gatech!n4hgf!wht, wht at n4hgf.Mt-Park.GA.US
When bad men combine,  the good must associate;  else they will  fall one by 
one, an unpitied sacrifice in a contemptible struggle. -Edmund Burke