[TUHS] non-blocking IO

[Paul Winalski]

On 6/2/20, arnold at skeeve.com <arnold at skeeve.com> wrote:
> Paul Winalski <paul.winalski at gmail.com> wrote:
>
>> 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.
>
> Also, the early Unixs were on smaller -11s, not the /45 or /70 with
> split I&D space and the ability to address lost more RAM.

I first encountered DOS/360 on a System/360 model 25 with 48K of
memory.  This was a one-job-at-a-time batch system, but the I/O
primitive (EXCP--execute channel program) was asynchronous.  So I
don't think the small memory rationale really applies.

-Paul W.