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 X-Received: by 10.50.117.10 with SMTP id ka10mr2007329igb.1.1409317566631; Fri, 29 Aug 2014 06:06:06 -0700 (PDT) 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!news.glorb.com!r2no9906085igi.0!news-out.google.com!aw9ni1123igc.0!nntp.google.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!nntp.earthlink.com!news.earthlink.com.POSTED!not-for-mail NNTP-Posting-Date: Fri, 29 Aug 2014 08:06:05 -0500 From: Dennis Lee Bieber Newsgroups: comp.lang.ada Subject: Re: STM32F4 Discovery, communication and libraries Date: Fri, 29 Aug 2014 09:06:38 -0400 Organization: IISS Elusive Unicorn Message-ID: References: <60a42dc6-d8d0-4432-ae5a-86de18b82840@googlegroups.com> <5kkrv9hejn2qhdckkeo8lidkbh3bkme1gn@4ax.com> <5b91313c-acf9-4a6e-b157-6ba7c8021567@googlegroups.com> <0513ad07-6fbe-463a-be6f-097cd5113f52@googlegroups.com> <4f1ec65a-d66a-40bf-a0d6-278fde206e70@googlegroups.com> <1cd027f2-a0e0-4206-b989-4aed2090cde8@googlegroups.com> X-Newsreader: Forte Agent 6.00/32.1186 X-No-Archive: YES MIME-Version: 1.0 X-Usenet-Provider: http://www.giganews.com NNTP-Posting-Host: 76.249.17.11 X-Trace: sv3-vshW7PnglkypqrqDoTaB5ctnN2IYB2wUP7EBpxkViu5BEDhOUnqYW2kXnFzMfiyVmXm0xc1ygMv4bpX!9pjJvMoVlhmBL8NYJBJMdZatuLqa76aiHhKDaTODP0N/9nG18msSbJNSrfHhweanEX/Q/kbZNttY!RSS76jem/dzsIbfdtXwCQ+Uz0g== X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 X-Original-Bytes: 3005 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Xref: news.eternal-september.org comp.lang.ada:21981 Date: 2014-08-29T09:06:38-04:00 List-Id: On Thu, 28 Aug 2014 13:34:58 -0700 (PDT), embeddedrelatedmike@scriptoriumdesigns.com declaimed the following: >On Thursday, August 28, 2014 1:09:05 PM UTC-7, Dmitry A. Kazakov wrote: >> Not really. OS is more than tasking, it is also a queueing mechanism, which >> allows waiting for I/O completion in one task without blocking all other >> tasks. >> ...... >> You could not implement an equivalent of I/O queueing under the Ravenscar >> constraints. > >Are you saying that a full Ada implementation on bare metal could not implement an equivalent of I/O queueing? > >Or are you saying that Ravenscar tasking on bare metal could not implement such queueing? Have you looked at the list of restrictions that profile requires? Max_Task_Entries = 0 (which goes along with) No_Select_Statements Max_Protected_Entries = 1 (effectively no queuing up for access to protected objects by multiple tasks) Simple_Barriers (plain T/F Boolean variable controlling entries) No_Relative_Delays (no "delay n" only "delay until m") Oh, and No_Abort_Statements (and a number of other restrictions) It works if the entire system including the "user application" level is built "as one". It is NOT a very dynamic arrangement wherein you may plug in a new sensor and have it magically install itself to some list of sensors to be reported. -- Wulfraed Dennis Lee Bieber AF6VN wlfraed@ix.netcom.com HTTP://wlfraed.home.netcom.com/