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.O921NxcpIxb8xZTHClyllQ.user.gioia.aioe.org!not-for-mail From: russ lyttle Newsgroups: comp.lang.ada Subject: Re: Why couldn't an operating system be written in ada Date: Wed, 27 Feb 2019 11:46:35 -0500 Organization: Aioe.org NNTP Server Message-ID: References: <4s8rud$9j3@tribune> <792fba1b-7a54-4d00-ae85-e6bd0737f001@googlegroups.com> NNTP-Posting-Host: O921NxcpIxb8xZTHClyllQ.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 (X11; Linux x86_64; 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:55701 Date: 2019-02-27T11:46:35-05:00 List-Id: On 2/27/19 10:55 AM, Dmitry A. Kazakov wrote: > 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 > I agree. The structure of C with its header files, #includes, etc., was just to fit the compiler and chunks of program into the machine. The process was start the compilation, go play Dungeon or Castle Wolfenstein or Star Trek in ascii art on a teletype for a while.