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" Newsgroups: comp.lang.ada Subject: Re: Point a beginner in the right direction? Cheap bare-board to run with a RTOS for running ADA Date: Sun, 7 Jul 2013 17:00:34 +0200 Organization: cbb software GmbH Message-ID: References: <8a3093bb-90b3-4081-9b0b-dfde5aa6b851@googlegroups.com> <993despcuk1d.1ifczvyo501px.dlg@40tude.net> Reply-To: mailbox@dmitry-kazakov.de NNTP-Posting-Host: xkOZ88C3T5fLavXpgyt3vA.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:16140 Date: 2013-07-07T17:00:34+02:00 List-Id: On Sun, 7 Jul 2013 10:58:24 +0000 (UTC), Simon Clubley wrote: > On 2013-07-07, Dmitry A. Kazakov wrote: >> On Sun, 7 Jul 2013 02:16:29 -0700 (PDT), Lucretia wrote: >> >>> Why not just buy a small SBC and just target Ada directly on the hardware. >>> You don't have to have an OS at all. >> >> There exist heaters better than a computer performing pointless >> calculations without any I/O. > > Sorry, Dmitry, but that's so out of touch I don't really know how to > respond so I will just say you don't need a OS to provide I/O services. > > You create some routines around the hardware which the rest of your code > can use to talk to the hardware and you structure your I/O support > library so that only the modules needed by the application are actually > linked in. And this is what basically an OS is - a set of routines around the hardware. Either the application does nothing beyond integer arithmetic or else you need an OS. Even most simple things like FPU or system timers would require functionality attributed to an OS. Any I/O on a modern machine would involve quite complicated hardware protocols like SPI, I2C, DMA, and extremely complicated software protocols like TCP and stuff upon it. The question is only who is going to write and maintain all this stuff. Just which is the ratio of he application code to "some routines around the hardware"? 1:0? 1:1? 1:1000? How about complexity of both? Small SBC + 1:1 suggests creation of a heater. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de