From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-0.3 required=5.0 tests=BAYES_00,
	REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4
Path: 
 eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Oberon and Wirthian languages
Date: Sat, 26 Apr 2014 10:09:05 +0200
Organization: cbb software GmbH
Message-ID: <15rd32v5ue5uf$.1hb4opfcuypec$.dlg@40tude.net>
References: <1ljwj8f.1wqbhvuabsdw1N%csampson@inetworld.net>
 <lj3540$m81$1@dont-email.me> <lj3nao$u22$2@dont-email.me>
 <lj4de1$jql$1@dont-email.me> <ly7g6hamsw.fsf@pushface.org>
 <lj5n4g$jse$1@dont-email.me> <brntbeFnfgcU1@mid.individual.net>
 <lj6kfg$jhs$1@dont-email.me> <lj6uhp$7dd$1@loke.gir.dk>
 <lj8aug$43b$1@dont-email.me> <ly61lzrciv.fsf@pushface.org>
 <lj9lbm$cig$1@dont-email.me> <brsggrFmd3gU1@mid.individual.net>
 <ljbmfm$j7u$1@dont-email.me> <brt9ftFrnkaU1@mid.individual.net>
 <ljce8q$qpb$1@loke.gir.dk> <ljekbl$bbt$1@dont-email.me>
 <ljeljn$sb3$1@loke.gir.dk> <bs121aFksntU1@mid.individual.net>
 <1zhiqb89npa6$.1z9j4otjchcb.dlg@40tude.net>
 <535b65cd$0$6716$9b4e6d93@newsspool2.arcor-online.net>
Reply-To: mailbox@dmitry-kazakov.de
NNTP-Posting-Host: AuYlnUSfTZrfhAkRjyySpQ.user.speranza.aioe.org
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
X-Complaints-To: abuse@aioe.org
User-Agent: 40tude_Dialog/2.0.15.1
X-Notice: Filtered by postfilter v. 0.8.2
Xref: news.eternal-september.org comp.lang.ada:19604
Date: 2014-04-26T10:09:05+02:00
List-Id: <comp.lang.ada>

On Sat, 26 Apr 2014 09:52:45 +0200, Georg Bauhaus wrote:

> On 26/04/14 09:36, Dmitry A. Kazakov wrote:
>> Many lock-free operations require more than merely pragma Atomic, e.g.
>> compare and swap etc.
> 
> Would it help if a Suspension_Object were implemented
> on top of CAS?

Wouldn't it be a locking primitive, regardless the means you used to
implement it?

> I understand that everything concurrent can be expressed
> with the help of consensus protocols, which in turn can
> be expressed in terms of CAS  only.

As a side point. My understanding is that though much can be theoretically
done, most of it will break at the point of software decomposition.
Concurrency primitives are especially non-composable.

>From the SW developing POV whatever primitives we put into the language
they must be local - have locally bounded effect, be textually local etc.

Anything done with the program as a whole (e.g. global optimization) may
take place, but only optionally. You cannot make the program dependent on
it.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de