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=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,a9bbfb8cd49f1a51 X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news3.google.com!news.glorb.com!blackbush.cw.net!cw.net!feed.news.tiscali.de!news.belwue.de!LF.net!news.enyo.de!not-for-mail From: Florian Weimer Newsgroups: comp.lang.ada Subject: Re: Isn't this in favour of Ada?? Date: Thu, 04 Aug 2005 14:59:35 +0200 Message-ID: <87ll3hyi14.fsf@deneb.enyo.de> References: <42d64dde$0$64794$edfadb0f@dread12.news.tele.dk> <8764vcdv2f.fsf@deneb.enyo.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: albireo.enyo.de 1123160387 32152 212.9.189.177 (4 Aug 2005 12:59:47 GMT) X-Complaints-To: Cancel-Lock: sha1:IOy4ovR0Pk8lufM/UPrxcOZZ7ok= Xref: g2news1.google.com comp.lang.ada:3954 Date: 2005-08-04T14:59:35+02:00 List-Id: * Larry Kilgallen: > In article <8764vcdv2f.fsf@deneb.enyo.de>, Florian Weimer writes: > >> I also fail to see Ada's advantages because Ada tasking tends to match >> poorly to concurrency models supported by operating systems. For >> example, how can you add a select alternative which waits for activity >> on a specific file descriptor, without introducing many pointless >> context switches? > > I don't know "file descriptor" as an Ada term, but presuming you mean > activity on a file, I would use the VMS Lock Manager requesting an AST > when there is activity (if I were creating an Ada implementation). But my point was that this has to be done by the implementor. It is something that is hard to resolve at a library level (unless you are willing to take the costs of a few additional context switches, of course).