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!feeder.eternal-september.org!aioe.org!.POSTED.fn3LatRFkm9/xzEj7F2/NQ.user.gioia.aioe.org!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: Why couldn't an operating system be written in ada Date: Wed, 27 Feb 2019 16:55:17 +0100 Organization: Aioe.org NNTP Server Message-ID: References: <4s8rud$9j3@tribune> <792fba1b-7a54-4d00-ae85-e6bd0737f001@googlegroups.com> NNTP-Posting-Host: fn3LatRFkm9/xzEj7F2/NQ.user.gioia.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Complaints-To: abuse@aioe.org User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 Content-Language: en-US X-Notice: Filtered by postfilter v. 0.9.2 Xref: reader01.eternal-september.org comp.lang.ada:55699 Date: 2019-02-27T16:55:17+01:00 List-Id: On 2019-02-27 14:54, russ lyttle wrote: > On 2/27/19 3:26 AM, Dmitry A. Kazakov wrote: >> On 2019-02-27 07:20, russ lyttle wrote: >> >>> That is all true. You could make the case that C turns your computer >>> into a PDP-11. I was being generous. >> >> Huh, you could not write >> >>     MOV -(PC),-(PC) >> >> in C, if I correctly remember the famous PDP-11 one-liner. >> > https://developers.slashdot.org/story/13/06/19/1227244/pdp-11-still-working-in-nuclear-plants---for-37-more-years > > >  In case the reader doesn't know the reference. IIRC, there was a way > to inject that code from a C program. As one commented, the code is on a > 9-track tape somewhere. Maybe an anecdote. The only C compiler for PDP-11 (for RSX-11M) I remember was a 5-stage monster which took an half an hour to compile hello-world. We programmed it mostly in MACRO-11 (an incredibly powerful assembler/preprocessor language). BTW, RSX-11M had pretty much powerful memory protection and virtualization. I remember tricks to gain an equivalent of root privileges, but most them were closed in late versions. All this on the machines with 256K RAM. If not the stupidity of management the first PCs could be LSI-11 based. https://en.wikichip.org/wiki/dec/lsi-11 -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de