Due to license restrictions on later Unix versions, the book was mainly distributed by samizdat photo-copying.

The source code for the original V6 Unix was later made available as free software under a BSD License from the SCO Group.

Wollongong Unix was the first ever port to a platform other than the PDP series of computers, proving that portable operating systems were indeed feasible, and that C was the language in which to write them.

[6] The resulting Portable C Compiler (PCC) was distributed with V7 and many later versions of Unix, and was used to produce the UNIX/32V port to the VAX.

(see Amdahl UTS) Bell Labs developed several variants of V6, including the stripped-down MINI-UNIX for low-end PDP-11 models, LSI-UNIX or LSX for the LSI-11, and the real-time operating system UNIX/RT, which merged V6 Unix and the earlier MERT hypervisor.