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=0.7 required=5.0 tests=BAYES_00,INVALID_DATE, MSGID_SHORT,REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ihnp4!ptsfa!ames!husc6!bloom-beacon!martillo From: martillo@bloom-beacon.UUCP Newsgroups: comp.lang.ada Subject: Re: Microsoft OS/2 -- Ideal for Ada Message-ID: <928@bloom-beacon.MIT.EDU> Date: Mon, 15-Jun-87 07:40:47 EDT Article-I.D.: bloom-be.928 Posted: Mon Jun 15 07:40:47 1987 Date-Received: Wed, 17-Jun-87 00:42:55 EDT References: <8706130340.AA00283@rand-unix.arpa> Sender: daemon@bloom-beacon.MIT.EDU Reply-To: martillo@athena.mit.edu (Yakim Martillo) Distribution: world Organization: MIT Project Athena List-Id: In article <8706130340.AA00283@rand-unix.arpa> hermix!fischer@rand-unix.ARPA writes: >Microsoft OS/2 (the replacement for MS-DOS for 286 machines) seems to have >everything which Ada's tasking management needs, and Unix doesn't provide. >Unlike the balky fork concept of UNIX, OS/2 treats parallel executions >within a process as threads, which look at first glance as if they were >designed with Ada rendezvous in mind; the threads can share the same >local data group, which is the opposite of UNIX fork semantics. The correct question is whether the language implementer should be mapping an Ada task into a Unix fork. The Unix process is an operating system entity which corresponds to a particular model of computation where user programs access a virtual machine in isolation from all other programs and request services and request services from the virtual machine via a generalized set of system calls to the operating system. Such a model makes logical i/o and piping really trivial. The Unix model is much more powerful than the multics or vms model of computation. Now the Ada task is a programming entity which may have some use in operating system develop and I would expect Ada tasking to compile to processor specific tasking instructions such as are present on the 80386 or 80286 if such are present. If such instructions are not present, the compiler would have to simulate tasking instructions just as a C compiler would simulate stack instructions on a machine which had no specialized stack instructions. Providing language level tasking by simulating non-existent tasking instructions should be no more than a couple of days work for the compiler writer. The implied criticism of Unix in this article is gratuitous and implies a lack of understanding. >Given the apparent compatibility of Ada with OS/2, I'd like to see a discussion >of compiler vendor plans for supporting OS/2... >(The only published public reference on OS/2 multiprocessing which I have >seen at newstands is in the May 1987 Microsoft Systems Journal, pg 29 ff.) > Herm Fischer I thought applications written in ADA were supposed to be portable.