On May 7, 21:33, Christian Fandt wrote: with my and see detailed or They won't help much with individual diagnostics, but they do tell you how to do things in general. Some time ago (about 11 years) I created a document about how to use XXDP; it's called "Notes for XXDP+ and XXDP V2 Operating Systems" and it's at http://www.dunnington.u-net.com/public/PDP-11/ In fact, IIRC, I put that doc on the web in response to a request from you (Christian) several years ago :-) There are PostScript and (thanks to the kind services of another listmember, Bill King) PDF versions. It's also mirrored on at least one other site which also has some XXDP info. XXDP is an enhanced version of the original XXDP (there's also one we used to refer to as XXDP++, but I'm not sure either name was offical), and V2 is what came out with the later microPDP-11s. V2 is a bit friendlier. The document consists of notes I made in the mid-80s when I was on a DEC maintenance course, plus reformtted stuff from the V2 files. So long as you remember that much of it uses the V2 commands, and replace them with the V1 equivalent, it will be useful. The one thing I never got round to doing -- because I have it on paper,in various forms -- is a list of *exactly* what each diagnostic is. There's a partial (very incomplete) list at http://www.chd.dyndns.org/pdp11/xxdp25.notes.txt See also http://starfish.osfn.org/rcs/pdp-11/xxdp/ Will Kranz also had some stuff -- he was working on how to completely decode an XXDP disk, but his site at earthlink has disapeared. those of three of .) I've never seen that, though I'm sure it will exist somewhere. If nowhere else, it should be at the front of any complete set of XXDP microfiche. a 11/53 Actually I think they are XXDP V2, now that I think about it (I don't have a system with an RX50 on it at the moment, to check). They'll test most of the basic hardware in the machine. Read the document and the list I referred to; it'll let you work out what hardware the tests are for. But to actually use certain of them effectively, you really ought to have the listings of the individual diagnostics. They don't all print nice messages; sometimes you need to know what the "switch settings" are to make them do certain things, sometimes they just halt on error and you can't tell what happened unless you can look up the error address in the listing. For example, for the ZKMA memory test: bit 15 set = halt on error bit 14 set = loop in selected subtest (see bits 0-3) bit 13 set = don't print errors bit 12 set = enable memory management bit 11 set = enable parity testing (default is ignore parity bits) bit 10 set = halt after each sub-test bit 9 set = don't do program relocation (so it can't test all of memory) bit 8 set = test in blocks of 4K, and print the first failing bit in each block bit 7 set = enable "long galloping test" (takes a while :-)) bit 6 set = don't size the memory (normally the diagnostic tries to work out how much memory there is to test) bit 5 set = don't print "END PASS xx" (normally does this every time round the loop) bit 4 set = don't print anything bits 0 to 3 are used to select a single subtest. See bit 14. Machines used to come with paper listings (though I think that practice stopped around the time of microPDP-11s) and some sites had the set on microfiche (one and a half boxes about 15" deep, so it's a LOT of microfiche for the whole set). We've discussed this on the list several times before. Maybe I should dig out the rest of my XXDP paper notes and scan them :-) -- Pete Peter Turnbull Network Manager University of York