Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!samsung!uunet!ecompin!netxcom!sundc!newstop!sun!snafu!lm
From: lm@snafu.Sun.COM (Larry McVoy)
Newsgroups: comp.unix.wizards
Subject: Re: What new system calls do you want in BSD?
Message-ID: <131446@sun.Eng.Sun.COM>
Date: 8 Feb 90 05:36:09 GMT
References: <12157@stealth.acf.nyu.edu> <7848@pt.cs.cmu.edu> <2212.21:08:11@stealth.acf.nyu.edu>
Sender: news@sun.Eng.Sun.COM
Reply-To: lm@sun.UUCP (Larry McVoy)
Distribution: usa
Organization: Sun Microsystems, Mountain View
Lines: 23

In article <2212.21:08:11@stealth.acf.nyu.edu> brnstnd@stealth.acf.nyu.edu (Dan Bernstein) writes:
>In article <7848@pt.cs.cmu.edu> dstewart@fas.ri.cmu.edu (David B Stewart) writes:
>> How about implementing good ol' semaphores, with a much simpler interface
>> than Sys V.
>
>Actually, I just built a simple threads library on top of my signal
>library. Everything is shared. You get threadfork(), threadexit(),
>threadup() and threaddown() for semaphores, and a few other calls.
>
>It ain't Mach but it works.
>
>---Dan

Yeah, I did the same thing once for kicks.  It's cute, but essentially useless.
You don't have threadkill() or threadsignal(), but you do have 
block_all_threads() in the form of read(), write(), select(), and any other
system call that can block().

Bottom line: threads without kernel support are largely useless.
---
What I say is my opinion.  I am not paid to speak for Sun, I'm paid to hack.
    Besides, I frequently read news when I'm drjhgunghc, err, um, drunk.
Larry McVoy, Sun Microsystems     (415) 336-7627       ...!sun!lm or lm@sun.com