MIT Releases the Source of MULTICS, Father of UNIX

mlauzon writes "Extraordinary news for computer scientists and the Open Source community was announced over the weekend, as the source code of the MULTICS operating system (Multiplexed Information and Computing Service), the father of UNIX and all modern OSes, has finally been opened. Multics was an extremely influential early time-sharing operating system and introduced a large number of new concepts, including dynamic linking and a hierarchical file system. It was extremely powerful, and UNIX can in fact be considered to be a 'simplified' successor to MULTICS. The last running Multics installation was shut down on October 31, 2000. From now on, MULTICS can be downloaded from an official MIT site (it's the complete MR12.5 source dumped at CGI in Calgary in 2000, including the PL/1 compiler). Unfortunately you can't install this on any PC, as MULTICS requires dedicated hardware, and there's no operational computer system today that could run this OS. Nevertheless the software should be considered to be an outstanding source for computer research and scientists. It is not yet known if it will be possible to emulate the required hardware to run the OS."

Comments

Hey Microsoft! Read the source and weep...

[toby]

Btw, it's "Multics" not "MULTICS".

Probably the best source for Multics-related information is this site.

The special hardware exists on 386s and later

[davecb]

There are two hard parts

1. Rings and ring-crossings, which are supported in intel hardware since the 286/386 era, and
2. Long words, longer than 32 bits.

Adresses and ints were 36 bits, longs were 72, and people used the 8th and 9th bits in in bytes for control and meta bits when manipulating raw terminal input.

Expect most of your problems will be with porting things like bit_offset_ entry (ptr) returns(fixed bin(24)) reducible

--dave (DRBrown.TSDC@HI-Multics.ARPA) c-b

Re:emulators?

[orangesquid]

Nope. The I/O hardware that the Level/68 system used was an extremely complex independent beast. (Think of SCSI (small computer systems interconnect) on steroids... since, uhh, Multics wasn't a "small computer system," but quite the opposite.) The documentation that survives is widely scattered; the few (insufficient) pieces that have been scanned and can be found on the web are at bitsavers. Much will likely have to be reverse-engineered.

I've been working on an emulator for a number of years. This article very good news, because it will make it easier for other people to get involved. (Note: don't bother trying to play with the emulator, because it is very... non-functional thus far. If you're interested in helping out, please do read everything at multicians.org, start following alt.os.multics, skim through everything on bitsavers, and then drop me a line *grin*).