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!rutgers!husc6!bloom-beacon!martillo From: martillo@bloom-beacon.UUCP Newsgroups: comp.lang.ada Subject: Re: Microsoft OS/2 -- Ideal for Ada Message-ID: <954@bloom-beacon.MIT.EDU> Date: Fri, 19-Jun-87 07:33:33 EDT Article-I.D.: bloom-be.954 Posted: Fri Jun 19 07:33:33 1987 Date-Received: Sat, 20-Jun-87 07:34:31 EDT References: <8706182337.AA09886@ucbvax.Berkeley.EDU> Sender: daemon@bloom-beacon.MIT.EDU Reply-To: martillo@athena.mit.edu (Yakim Martillo) Distribution: world Organization: MIT Project Athena Summary: Fundamental Operating System Entities List-Id: In classic unix, like I first used in 1975 the fundamental operating system entities were files and processes. If you understood everything there was to understand about files and processes you understood everything. The tty was a file, the directory was a file, and the pipe was an unnamed file. The process was just about the only entity that was not a file. (Actually this is not quite true, there were a few other objects like interrupt handlers which fit in neither category) but in general there was nothing more which you really needed to understand. Multics was in some sense even simpler. There is one fundamental entity, the memory segment (though one could argue that the user's tty was also a fundamental entity, but the importance of the user's tty is perhaps more properly viewed as a result of the way Multics does I/O). Unfortunately this seems to be a bad choice of fundamental entities especially for me since I consider segmenting memory a stupid thing to do and based on a fundamental misconception that one wants to protect regions of memory rather than operating system objects. As for VMS and the various IBM operating systems, I am not sure what the fundamental entities are and have the feeling that everything is special cased which makes comprehension harder.