Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!att!emory!tridom!n4hgf!wht From: wht@n4hgf.Mt-Park.GA.US (Warren Tucker) Newsgroups: comp.unix.misc Subject: Re: Interprocess Communication / Multitasking Message-ID: <320@n4hgf.Mt-Park.GA.US> Date: 16 Feb 91 07:43:12 GMT References: Sender: wht@tridom.uucp (Warren H. Tucker) Reply-To: wht@n4hgf.Mt-Park.GA.US (Warren Tucker) Distribution: usa Organization: Amateur Radio Station N4HGF Lines: 27 In article bradfrd2@ncar.ucar.edu (Mark Bradford) writes: > >Here's the project: a real time data ingestion and archival system, >built from several multitasking and cooperating programs using >They say that UNIX is "notoriously lacking" in the necessary >constructs to do this multitasking UNIX lacks "lightweight processes," threads which execute within a single address space (alas), but System V has all of the necessary mechanisms for classical coprocessing (shared memory, messaging, semaphores), so on the Sun you are in luck. BSD has a (usually unimplemented) mmap call which can support shared memory, but lacks the other formal mechanisms you need (there are hacks, but they are hacks). You probably heard of "lacking" in reference to BSD. System V IPC has a bad name, but only among those have little experience with the concepts involved or who have `enjoyed' exposure to it on broken implementations. The only pseudoproblem I have ever had with it is key selection algorithms. With a 32-bit key `space', key management is problematical, but usually practicable. ----------------------------------------------------------------------- Warren Tucker, TuckerWare gatech!n4hgf!wht or wht@n4hgf.Mt-Park.GA.US Many [Nobel physics] prizes have been given to people for telling us the universe is not as simple as we thought it was. -Stephen Hawking in A Brief History of Time In computing, there are no such prizes. -me -- ---------------------------------------------------------------------------- Warren Tucker, Tridom Corporation, gatech!n4hgf!wht, wht@n4hgf.Mt-Park.GA.US When bad men combine, the good must associate; else they will fall one by one, an unpitied sacrifice in a contemptible struggle. -Edmund Burke