Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!wuarchive!uunet!crdgw1!crdos1!davidsen
From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr)
Newsgroups: comp.arch
Subject: Re: Async system interface
Message-ID: <3181@crdos1.crd.ge.COM>
Date: 6 Feb 91 16:30:44 GMT
References: <3177@crdos1.crd.ge.COM> <13772@lanl.gov>
Reply-To: davidsen@crdos1.crd.ge.com (bill davidsen)
Organization: GE Corp R&D Center, Schenectady NY
Lines: 16

In article <13772@lanl.gov> jlg@lanl.gov (Jim Giles) writes:

| The fact that UNIX is badly designed, doesn't rule out the possibility
| of other bad systems.  You should never be forced to do a wait system
| call if what you want is synchronous I/O.  

The solutions are either a WAIT call, a separate SIO call for blocking
i/o, or a flag to be supplied on each and every i/o system call. The
systems I used all had the first, some had the second. Using a flag adds
size to the calling program, CPU overhead to set and test the flag, and
appears on first glance to have no advantages over the others. The
separate blocking i/o system call is probably lowest overhead.
-- 
bill davidsen	(davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
  "I'll come home in one of two ways, the big parade or in a body bag.
   I prefer the former but I'll take the latter" -Sgt Marco Rodrigez