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=unavailable autolearn_force=no version=3.4.4 Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!mx02.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: Advice, tasking and hardware Date: Tue, 7 Jun 2016 22:21:04 +0200 Organization: Aioe.org NNTP Server Message-ID: References: <25c43463-47ca-4021-82ee-299e6a075faa@googlegroups.com> <2c0dfaf8-9344-4b9c-87b4-12de687687ce@googlegroups.com> <0dc88dae-098b-4282-b1da-4798cc14131d@googlegroups.com> <8ada2408-b58b-4a32-bc95-f90689d5a8e4@googlegroups.com> NNTP-Posting-Host: w/2xSGckQeJEFvqsQFNodA.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; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 X-Notice: Filtered by postfilter v. 0.8.2 Xref: news.eternal-september.org comp.lang.ada:30649 Date: 2016-06-07T22:21:04+02:00 List-Id: On 2016-06-07 18:53, rieachus@comcast.net wrote: > On Monday, June 6, 2016 at 3:19:20 AM UTC-4, Dmitry A. Kazakov wrote: > >> As questionable aborting task is, if do, that is unrelated to any >> protected objects. They block nothing unless erroneous, e.g. when you >> run an infinite loop within a protected action. If you do you would not >> be able to abort the task stuck in the action, it is abort-deferred. > > Sigh! This is the one instance where aborting a task is not just > appropriate, but sometimes necessary. I have no control over, for > example, bit flipping by cosmic rays. Why do you think aborting task would heal that? Why not zeroing a random section of memory, sending an SMS, or assigning 666 to the process counter? > If the deadman timer runs out, > there is a serious problem and the airplane (or launch vehicle) is > falling out of the sky. Yes, but that is not to address by some random actions. You have to bring the system to the nearest known safe state. Restarting a task might be one, unless the cosmic ray hit the task body's code, external objects the task uses, other tasks and hardware it communicates to etc. Regarding protected objects, an equivalent of aborting task is deleting the protected object and creating another instance of. If you believe in voodoo magic protected objects are as good as tasks. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de