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The Last Multics System Decommissioned
Bell Would? writes: "A key feature of the brief news item, 'The end of the Multics era,' in the latest issue of the The Risks Digest is the 'list of goals' Multics had fulfilled which, as the author describes them, are as relevant today as they were 35 years ago." Odd -- I assumed these were all long since junked or put into museums, since my first exposure to the name Multics was in books which spoke mostly in the past tense. That list of goals is one that I hope architecture designers consult frequently.
I had the "opportunity" to work as a systems operator on *6* Multics systems, from 1986 to 1988. (Yes, I'm listed with Multicians.org.) Your interpretations of some of the goals of the Multics project is somewhat colored by modern technology. Let me explain what some of those goals meant to the Multicians, and why they still aren't met by modern operating systems:
This meant that the entire system was hot swappable: disk drives, CPUs, Memory units, IO units. Of course, your odds of the system surviving the addition or subtraction of any one of these were
This is the hot-swappable hardware thang again. You could add a CPU to a system without interrupting the processing on the rest of the system. System software updates were quite a different matter -- that generally required a system restart, and there were still "system" drives whose failure could cause the entire system to crash.
This refers to classifying information, not filesystems. Multics could run with Classified, Secret, and Top-Secret information (and programs) all co-resident, and without a lower-classification program being able to access higher-classification information. No modern operating system works this way; the set of systems that replaced the Multics group that I worked on was *3* separate Unix networks, one for each security classification.
This refers to the traditional hierarchical file structure, with hierarchical user management thrown in for good measure. What CP/M and MS-DOS stole from Unix, Unix in turn stole from Multics.
In general, Multics achieved its goals, though the cost was too high. More recent operating environments have judged the cost of some of those goals (primarily security) to be so unrealistic as to be completely undesirable. While I think that Multics aimed too high on some goals, I think that too many operating systems (including Linux) aim too low.
Are you moderating this down because you disagree with it,
We call it art because we have names for the things we understand.
Most of the large airline systems run on IBM's Transaction Processing Facility (TPF). IBM keeps updating it, even added TCP/IP a few years back, but it's essentially 1960's technology. By the way, go to a web site like Expedia or even the new Orbitz site and you're still hitting mainframe assembler code in the background somewhere... Try these on for size: most applications are written in assembler, manually divided into 4K blocks. No virtual memory, all storage preallocated at sysgen into fixed size blocks (woohoo - no fragmentation!). No filesystem, all you get is a shitload of blocks (381 bytes, 1055 bytes, 4K) and it's up to the programmer to do the rest. I've seen code on these systems that was written in 1970-1972 and is still in use today, taking thousands of transactions per second. Somehow I don't see W2K apps lasting 30 years.
Not anymore. Real Men use BSD.