By D. M. Ritchie and K. Thompson
Unix is a general-purpose, multi-user, interactive operating system for the larger Digital Equipment Corporation PDP-11 and the Interdata 8/32 computers. It offers a number of features seldom found even in larger operating systems, including
- A hierarchical file system incorporating demountable volumes,
- Compatible file, device, and inter-process I/O,
- The ability to initiate asynchronous processes,
- System command language selectable on a per-user basis,
- Over 100 subsystems including a dozen languages,
- High degree of portability.
This paper discusses the nature and implementation of the file system and of the user command interface.