Real-time UNIX - what is it & who has it?

[H. L. Rogers]

In article <649 at necis.UUCP> adamm at necis.UUCP (Adam Moskowitz) writes:
>I'm sure this has been asked before, but here goes again anyway . . .
>
>A friend of mine has asked to help him locate a "real-time UN*X or UN*X-like
>operating system".  I told him that VenturCom "claims" to sell such a beast,
>but some discussion of their product ensued that led to the following
>question:
>
>    Assuming that you are doing something like data acquisition or
>    process control, what is required to make an O/S "real-time"?

I suggest you call Bill Corwin at Intel.  He is chairman of the IEEE
1003.4 committee on real-time for Un*x.  That committee was spawned by
/usr/group in 1984-or-so and is doing some very nice work in defining
the attributes of a real-time system.  You were right about
scheduling; it is crucial to have control of process priorities to
guaranteee deterministic performance.  But that's not all you need.
Things like user access to I/O space, fast IPC, process memory
residency to completion, etc. will buy you larger chunks of
performance and *predictability*.
>
>So, given that, who makes what he needs?  We know that Charles River Data
>Systems has something called UNOS that supposedly does that.  Does it?  Does
>anyone else know of anything else that is available?

HP, IBM (allegedly), Masscomp, NCR.  There are probably others...just
can't think of them.

-- 

------------
HL Rogers    (hl.rogers at ncrcae.Columbia.NCR.COM)