> From: Steven Malikoff > I'm wondering if there are any more differences apart from the lack of > the two high address switches?
According to the -11/15-20 processor manual (pg. 2), the differences between the two are i) the -15 has only one hardware interrupt level, not four (the latter is optional), and ii) power-fail restart is an option, not standard. > Presumably the /15 could not run one of those KT-11 paging units I'm not sure how the KT11-B works, but my _suspicion_ (going from the pictures of that one that sold on eBay) is that it's not part of the CPU, but a UNIBUS device, which maps part of the UNIBUS which the CPU _can_ see (i.e. in the 0-56KB range) up to higher addresses, where the 'extra' memory is configured. If that supposition is correct, it would work equally well on any -11 (without built-in memory mapping in the CPU). Noel