Standards Update, IEEE 1003.4: Real-time Extensions

Doug Gwyn gwyn at
Sat Sep 29 02:06:42 AEST 1990

Submitted-by: gwyn at (Doug Gwyn)

In article <541 at usenix.ORG> brnstnd at (Dan Bernstein) writes:
>In the filesystem abstraction, you open a filename in one stage. You
>can't do anything between initiating the open and finding out whether or
>not it succeeds. This just doesn't match reality, and it places a huge
>restriction on programs that want to do something else while they

UNIX was designed explicitly on the model of communicating sequential
processes.  Each process acts as though it executes in a single thread,
blocking when it accesses a resource that is not immediately ready.
While it would be easy to argue that there is a need for improved IPC,
I haven't heard any convincing arguments for making asynchronity
explcitly visible to a process.  In fact, it was considered quite a
step forward in computing back in the old days ("THE" operating system,
for example) when viable means of hiding asynchronity were developed.

Volume-Number: Volume 21, Number 144

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