Unix V4 found in Utah University

[AGTDenton]

Quite the find from a mostly analogue era.

The operating system was originally written in PDP-7 assembly language, and ported to PDP-11 assembly language in 1970, but in 1973, Version 4 Unix was rewritten in C. Ken Thompson faced multiple challenges attempting the kernel port due to the evolving state of C, which lacked key features like structures at the time. Version 4 Unix, however, still had much PDP-11 specific code, and was not suitable for porting. The first port to another platform was a port of Version 6, made four years later (1977) at the University of Wollongong for the Interdata 7/32, followed by a Bell Labs port of Version 7 to the Interdata 8/32 during 1977 and 1978.