LOCUS (operating system)
| Developer | UCLA |
|---|---|
| OS family | Unix |
| Working state | Historic |
| Source model | Closed source |
| Kernel type | Monolithic kernel |
| License | Proprietary |
LOCUS was a distributed operating system developed at UCLA during the 1980s. It was notable for providing an early implementation of the single-system image idea, where a cluster of machines appeared to be one larger machine.
A desire to commercialize the technologies developed for LOCUS inspired the creation of the Locus Computing Corporation which went on to include ideas from LOCUS in various products, including OSF/1 AD and, finally, the SCO–Tandem UnixWare NonStop Clusters product.
The LOCUS system was created at UCLA between 1980 and 1983, initial implementation was on a cluster of PDP-11/45s using 1 and 10 megabit ring networks, by 1983 the system was running on 17 VAX-11/750s using a 10 megabit Ethernet. The system was Unix compatible and provided both a single root view of the file system and a unified process space across all nodes.
The development of LOCUS was supported by an ARPA research contract, DSS-MDA-903-82-C-0189.
In order to allow reliable and rapid access to the cluster wide filesystem LOCUS used replication, the data of files could be stored on more than one node and LOCUS would keep the various copies up to date. This provided particularly good access times for files that were read more often than they were written, the normal case for directories for example.
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