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 2002:a05:6638:198:: with SMTP id a24mr3848481jaq.10.1554611521481; Sat, 06 Apr 2019 21:32:01 -0700 (PDT) X-Received: by 2002:a05:6830:12d2:: with SMTP id a18mr14897051otq.156.1554611521308; Sat, 06 Apr 2019 21:32:01 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!feeder.eternal-september.org!weretis.net!feeder6.news.weretis.net!feeder.usenetexpress.com!feeder-in1.iad1.usenetexpress.com!border1.nntp.dca1.giganews.com!nntp.giganews.com!b2no86899itd.0!news-out.google.com!r82ni407ita.0!nntp.google.com!136no285730itk.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Sat, 6 Apr 2019 21:32:00 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=96.255.209.31; posting-account=zwxLlwoAAAChLBU7oraRzNDnqQYkYbpo NNTP-Posting-Host: 96.255.209.31 References: <4s8rud$9j3@tribune> <1ae2b744-f80b-4450-b8d3-7b49fca01f15@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: Subject: Re: Why couldn't an operating system be written in ada From: Optikos Injection-Date: Sun, 07 Apr 2019 04:32:01 +0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Xref: reader01.eternal-september.org comp.lang.ada:56093 Date: 2019-04-06T21:32:00-07:00 List-Id: On Saturday, April 6, 2019 at 9:55:21 PM UTC-4, Nick Roberts wrote: > On 10/01/2019 23:38, cenci.br@gmail.com wrote: > > Em s=C3=A1bado, 13 de julho de 1996 04:00:00 UTC-3, Mark McKinney esc= reveu: > >> It has been claimed that the capability to interface with other langua= ges > >> is a great asset to ada. Sometimes interfacing can be a tremendous > >> liability. Besides the OS could perform most of work that the language > >> runtime does. So why not build an OS in ADA? > >=20 > > Is this discussion still active ? >=20 > I have a little bit of a plan for this, but I must admit it is very=20 > ambitious. The biggest problem I face is getting help, as well as my own= =20 > lack of skill in running these projects. >=20 > My current plan goes along these lines: >=20 > I am building a new Ada compiler that will use a new technology for=20 > targeting machine architectures. The following is a simplification, but= =20 > it gives the gist of it. >=20 > 1. The compiler builds Ada source text into an intermediary code, called= =20 > 'PXC' (a kind of abbreviation for 'extended pseudo-code'). These PXC=20 > files are distributed to the target machines. Each PXC file is a module,= =20 > and a complete program comprises many such modules (perhaps hundreds of= =20 > them, or even thousands). >=20 > 2. Each target machine itself has a program called the Realizor, which=20 > generates a real executable file, comprising actual machine code for the= =20 > architecture of its own processor(s), from the complete set of PXC=20 > modules that go to make up the program. >=20 > One of the big advantages of doing it this way is that global=20 > optimisations, including inlining of cross-module calls, can be=20 > performed by the Realizor. In addition, the Realizor can implement a=20 > strategy of capturing profiling data (execution statistics) for the=20 > program, and periodically re-realising it to yield still better=20 > optimisations. >=20 > 3. Because of the way the Realizor works, all privilege level-changing=20 > calls (e.g. into the kernel) can be removed. Security is, nevertheless,= =20 > fully maintained. >=20 > (I also intend the technology to remove all use of hardware paging; this= =20 > will be replaced by a more intelligent software-based segment-swapping=20 > mechanism.) >=20 > 4. Because of 3 above, it is possible for the kernel and all the device= =20 > drivers and other low-level software to be PXC modules, mixed in by the= =20 > Realizor along with all the other PXC modules. This means that many=20 > kernel calls can be inlined, effectively eliminating all call overhead=20 > on them. >=20 > I believe these technologies would enable a dedicated piece of software,= =20 > running 24/7, to run significantly faster. >=20 > When you consider how important performance is on today's vast farms of= =20 > servers, that could be a pretty compelling reason for people to switch=20 > from traditional operating systems. >=20 > All I have to do is to do it :-) >=20 >=20 >=20 > I'm hoping it could be a way of getting Ada back into the mainstream. We= =20 > all know in this forum that building future software in Ada, especially= =20 > server software, would be a big step towards making it more secure and=20 > reliable. >=20 > PS: There's a lot more about this scheme that I would like to say, but I= =20 > don't want to turn this post into a dissertation, and I do want to get=20 > to bed soon. If you have any burning questions, please ask. Why can't LLVM be your PXC? LLVM already is your PXC and already built out= your Realizors for a plethora of ISAs.