Unix History

[a.reed]

> This raises the burning question:  whatever happened to
> Systems I and II, and, especially, IV?  I never hear them
> discussed.  Were they ever released commercially, and if
> not, why not?
> 					Scott Anderson
> 					ihnp4!oddjob!kaos!sra

System numbers correspond to releases standardized by the
Bell Labs' UNIX Support Group (USG) and its successor
organization in AT&T IS Computer Systems Division. Roman
numbers are used for external releases and arabic numbers
for the corresponding internal releases. There were no
external releases corresponding to USG internal systems
1, 2, and 4. USG System 4 did not have enough functionality
beyond that available in USG System 3/III to justify a
separate external release.
					Adam Reed
					ihnp4!npois!adam