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: Thu, 1 Oct 2020 11:28:10 +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 Content-Language: en-US X-Notice: Filtered by postfilter v. 0.9.2 Xref: reader02.eternal-september.org comp.lang.ada:60351 List-Id: On 01/10/2020 00:42, Randy Brukardt wrote: > "Dmitry A. Kazakov" wrote in message >> P.S. Surely MS-DOS coordinated auxiliary processors, there exited lots of >> expansion cards with processors on them in MS-DOS times. > > I suppose, that was done with device drivers and the like, below anything > visible. I don't remember every worrying about what was happening on cards, > anymore than one does nowdays on Windows or Linux. It was so simpler then. Usually a dual-ported RAM was used for communication. Today's hardware interfaces are faster but incredibly complicated. >> P.P.S. In MS-DOS processes were coordinated using glorious INT 21h. (:-)) > > Since there wasn't any extra processing (no cores back then), anything > working like a process was a hack. Janus/Ada used (and still uses) > cooperative multitasking to give the appearance of multiple processes, but > no such thing was actually happening. Given that MS-DOS itself wasn't > re-enterant, it was too risky to use any sort of conventional > interrupt-driven tasking. (Some people did it anyway, by trusting various > undocumented hacks; there even was a famous book about those - which came > out way too late to influnce the Janus/Ada design.) Yes, Ada tasking intermixed with I/O was a nightmare. It is so much better now, that the only place left where you do need to care about that stuff is during a protected action. BTW, I still do not know to design an Ada-conform tracing/logging facility such that you could trace/log from anywhere, protected action included, and without knowing statically which protected object is involved. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de