From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.5-pre1 (2020-06-20) on ip-172-31-74-118.ec2.internal X-Spam-Level: X-Spam-Status: No, score=-1.9 required=3.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.5-pre1 Path: eternal-september.org!reader02.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED.2uCIJahv+a4XEBqttj5Vkw.user.gioia.aioe.org!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: is there a version of unix written in Ada Date: Fri, 2 Oct 2020 08:56:38 +0200 Organization: Aioe.org NNTP Server Message-ID: References: <00cd3aaa-d518-43a2-b321-58d6fae70aebo@googlegroups.com> <57eb7a65-51ea-4624-b9dc-9c4dda0fee59n@googlegroups.com> <5f70fd3b$0$13541$426a74cc@news.free.fr> <87wo0d3iac.fsf@nightsong.com> <87sgb02l7b.fsf@nightsong.com> <875z7vyy1u.fsf@nightsong.com> <87wo0bkns3.fsf@nightsong.com> NNTP-Posting-Host: 2uCIJahv+a4XEBqttj5Vkw.user.gioia.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: abuse@aioe.org User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.3.1 X-Notice: Filtered by postfilter v. 0.9.2 Content-Language: en-US Xref: reader02.eternal-september.org comp.lang.ada:60381 List-Id: On 02/10/2020 07:36, J-P. Rosen wrote: > To continue on Randy's response: mutual exclusion is not blocking. > "Blocking" (as in "potentially blocking operation") means "being put on > a queue", i.e. when the waiting time is potentially unbounded. It would be a poor definition, because deadlock in not bounded as well. If jumping from one protected object to another is legal, we can construct a deadlock out of mutual exclusion. We also have a situation when multiple tasks executing protected procedures are awaiting their turn to enter a procedure of some object. They will continue (if not deadlocked) in some order, which is obviously a queue. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de