Path: utzoo!attcan!uunet!husc6!uwvax!oddjob!ncar!gatech!mcnc!ece-csc!ncrcae!ofc!rogers From: rogers@ofc.Columbia.NCR.COM (H. L. Rogers) Newsgroups: comp.unix.questions Subject: Re: Real-time UNIX - what is it & who has it? Keywords: real-time, process control Message-ID: <203@ofc.Columbia.NCR.COM> Date: 23 Jun 88 12:38:25 GMT References: <649@necis.UUCP> Reply-To: hl.rogers@ncrcae.Columbia.NCR.COM (H. L. Rogers) Distribution: na Organization: NCR Corp, E&M-Columbia, W Columbia, SC Lines: 32 In article <649@necis.UUCP> adamm@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@ncrcae.Columbia.NCR.COM)