Reanimating a PDP-11/23

On 05/12/2009 11:46, Pontus Pihlgren wrote: They will. The MSV11-D memory and your H9273 backplane will support 18-bit addressing, and so as long as you don't try to run things as a 22-bit system, they'll work fine. A KDJ11-A or KDJ11-B will happily work as an 18-bit system if that's what they're in, just as your KDF11 does (it's also 22-bit, if it has the MMU). There's no practical way to upgrade the MSV11-D to 22-bit, but if you do want to upgrade the backplane, it's not very hard to link together the relevant pins for the additional 4 signal lines by soldering wire-wrap wire down the backplane. If you do that, the system, including the MSV11-D will still work fine as an 18-bit system so long as you don't try to put memory in the area from 256KB to 4MB. If you want to go further than 256KB, remember that your BDV11 is also only 18-bit, unless it's Revision F or later. However, there's an ECO to convert it to 22-bit if necessary. And if you want more memory than 256KB, you'll need to replace the MSV11-D with something else. Early DLV11-J boards are supposedly not compatible with even KDF11 processors, but I can't remember why. Anyway, yours works, apparently, so presumably it's not too early, and will also with with a KDJ11. -- Pete Peter Turnbull Network Manager University of York