It's too bad it's not 'between V2 and V3', since the UNIX kernels V2 and V3 are missing. (V4 is the earlist one that we have, after the V2 and onward gap.) So, depending on how far from V1 (which we have) it is, it _might_ be worth dis-assenbling. It would be particularly worth having it if it suppports the KS11, since almost no documentation of that has survived; code that uses it would allow re-creation of a programming manual for it. I don't think it can be the /45; as of V2, the /45 was apparently expected in the near future, and this was before the V2. Noel