On 2012-12-18 15:45, Paul_Koning at Dell.com wrote: On Dec 17, 2012, at 6:01 PM, Johnny Billquist wrote: On 2012-12-17 23:50, Boyanich, Alastair wrote: ... 2) Was 2.11BSD ever ported to other platforms? Given the age/era, I'm curious about 8088/8086/NECv20/80286 given the banked memory models used and looking at the 8088/8086 XENIX disassembly. Nope. That would not have been 2BSD then. And since the PDP-11 don't even have banked memory, it would probably cause some headaches to port 2BSD to something like 80286 or other similar machines. To make it clear - the PDP-11 have a very normal MMU with pages. Semi-normal. It's rather unusual in that it has a paged MMU with page address granularity different from the page size (64 bytes vs. 8k bytes). Most architectures have those two match, that avoids an adder -- consider VAX or MIPS or Alpha. Details. :-) Just consider it an extra feature. However, I think it is actually pretty common in a way today, when you have different page sizes on the MMUs. (But I have not looked exactly how you can use them.) Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol