[TUHS] non-blocking IO

Paul Winalski paul.winalski at gmail.com
Wed Jun 3 03:45:55 AEST 2020

The operating systems that I cut my teeth on (OS/360, DOS/360,
VAX/VMS) all had basic I/O system calls that were non-blocking.
Blocking I/O calls were all built on top of that framework.  I thus
found it curious that Unix took the opposite tack, and non-blocking
I/O was an afterthought.

So I'm curious as to what the rationale was for Unix to have been
designed with basic I/O being blocking rather than asynchronous.
Especially that non-blocking I/O primitives were the norm for OSes in
those days.

-Paul W.

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