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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: comp.arch,comp.unix.wizards,comp.os.minix
Subject: Re: Free Software Foundation (was: Re: Mach, the new standard?)
Message-ID: <8636@utzoo.UUCP>
Date: Mon, 21-Sep-87 21:00:05 EDT
Article-I.D.: utzoo.8636
Posted: Mon Sep 21 21:00:05 1987
Date-Received: Mon, 21-Sep-87 21:00:05 EDT
References: <1665@ncr-sd.SanDiego.NCR.COM> <8381@utzoo.UUCP>
Organization: U of Toronto Zoology
Lines: 14

> Most uses of fork() are immediately followed by an exec() call.  Why
> else do you think the BSD people came up with vfork()?  A direct "start
> program in a seperate process" call would accomplish the same effect
> and would be easily implementable on machines without hardware support
> for (the right flavor of) virtual memory.  

Be careful.  Most uses of fork() are *not* immediately followed by an
exec() call; the two are usually separated by some manipulation of things
like file descriptors and signals.  A combined fork-exec is definitely
possible, since the OS/9 people did it, but it's not as simple as it
sounds at first.
-- 
"There's a lot more to do in space   |  Henry Spencer @ U of Toronto Zoology
than sending people to Mars." --Bova | {allegra,ihnp4,decvax,utai}!utzoo!henry