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Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!hao!husc6!ut-sally!ut-emx!chcu275
From: chcu275@ut-emx.UUCP (Noel Bell)
Newsgroups: comp.unix.xenix,comp.unix.wizards
Subject: correction to request for shared memory synchronization info.
Message-ID: <969@ut-emx.UUCP>
Date: 25 Feb 88 05:59:53 GMT
Organization: The University of Texas at Austin, Austin, Texas
Lines: 30
Keywords: shared memory, process control, GPIB, synchronization


 The following is a re-posting of a previous article with the correct
 name for the SCO XENIX shared memory routine (sdwaitv) :

  I am using SCO XENIX 2.1 to read and write data on an IEEE-488 GPIB
  interface.  The XENIX op. sys. runs on an AT which serves as a 
  supervisor to a XT slave.  The reads are set up to occur at a specific
  time interval.  The writes occur at a specific time interval but also
  can occur at arbitrary times.  

 * begin corrected paragraph*

  What is the best way to synchronize this GPIB activity?  Should I use
  "sdwaitv" with shared memory to delay action until the current read or 
  write leaves the shared memory? ( I think this would be similar to 
  using semaphores on Sys 3 which are not supported on  Sys V. according 
  to my manuals. )

 *end of corrections*

  I would appreciate any advice on this matter.  Also, are there any good
  references for process control on UNIX/XENIX systems that provide more
  info. than the SCO or UNIX Sys.V manuals.

  Thanks in advance for any suggestions provided.

 I apologize for the necessity of repeating this posting.

  Noel Bell
  Department of Chemical Engineering
  Univ. of Texas at Austin