Hi Noel,
may I draw your attention to
http://www.tuhs.org/Archive/Distributions/Research/Bug_Fixes/V6enb/ ?
There you'll find some modification to Unix V6. They are distributed as what I call
.enb. This suffix stands for “enblocked”. Enblocking means marking blocks on a tape file
suitable for simh. You’ll find more about V6 and the modifications at
http://doc.cat-v.org/unix/v6/operating-systems-lecture-notes/
Greetings,
Wolfgang Helbig
Stauferstr. 22
71334 Waiblingen