BTW:  My memory is that Joy did not like them for some reason,
probably because they were not as sexy as some of the stuff Accent could do
(but that's a guess -- I've forgotten).  So with 4.2, Joy created Unix
domain sockets.

BTW: a slow cache refresh is occurring in my brain ... I remember one of
the things that there was a lot of arguing/moaning about at the time was
the directionality of such a feature.  Bruce's hack from the mid-70s was
unidirectional and you needed two pipes to go both ways.

On Fri, Mar 6, 2020 at 4:06 PM Clem Cole <clemc@ccc.com> wrote:

> The first version was from Rand (called "Rand Pipes").   They
> certainly were available in the mid-70s on Sixth Edition, you have to ask
> someone like Bruce Borden if they were on Fifth.  I think the code is on
> one of the 'USENIX' tapes in Warren's archives.
>
> At this point in time, someone would need to refresh my memory of the
> details of Rand's implementation compared to what came in the USG systems
> in the 1980s.   For instance, I believe the early versions used mknod(2) to
> create the "named entity."   IIRC early USG did that too, and mkfifo(3)
> came as part of the POSIX (I have memories of the discussion at a POSIX
> meeting, but as I say, I've forgotten the details).
>
> IIRC there were differences in buffering behavior, flushing, error path
> between USG's later versions and the original Rand, but I'd have to stare
> at the code again to remember.
>
> On Fri, Mar 6, 2020 at 3:42 PM Paul Ruizendaal <pnr@planet.nl> wrote:
>
>> The Luderer paper on distributed Unix has the following paragraph:
>>
>> "A new special UNIX interprocess communication mechanism is the fifo,
>> which provides communication between unrelated processes by associating a
>> new special file type with a file name. Since remote fifos are legal, they
>> can be used for interprocessor communication between S-UNIX machines or
>> between an S-UNIX machine and an F-UNIX machine.”
>>
>> The paper is from late 1981. Maybe I’m especially mud-eyed today, but I
>> cannot see FIFO’s implemented in V7..V8 or 4.1xBSD. When did FIFO’s become
>> a standard Unix feature?
>>
>> Paul
>>
>>