Hi Mitch, you'll find the program enblock.c at http://www.ba-stuttgart.de/~helbig/os/v6/ that I wrote to prepare the v6 distribution tape for SIMH. With v7, you need to apply different block sizes like (f0, f1, ... f6 from Keith Bostic): enblock <f0 >dist.tap enblock <f1 >>dist.tap ... enblock <f4 >>dist.tap enblock 10240 <f5 >>dist.tap enblock 10240 <f6 >>dist.tap enblock </dev/null >>dist.tap Enblock puts an EOF tapemark at the end. The last invocation puts an EOT mark. Have fun, Wolfgang