Hello all! Let's try to summarize the problem. RTPAD.EXE is the executable image behind SET HOST and SET HOST/APP=R on VMS, and it can use both CTERM and RTERM protocols to connect to remote systems. Some older OSes, notably TOPS-10 and RSTS (and others, I suppose), do either behave badly when accessed with the newer CTERM protocol, mainly because it's too VMS-centric, or do not work at all because they do not suppport it. To connect to them, the solution is to always use the older RTERM protocol. RTPAD.EXE on OpenVMS V8.3 for both Alpha and Itanium (IIRC) has some serious bug that prevents it from connecting to such older OSes using the old RTERM protocol: actually it ACCVIOs before doing any useful work. The RTERM protocol can be used to connect to VMS too, and when connecting to another VMS node using RTERM, the V8.3 RTPAD.EXE works as expected. So, either some older OSes are sending out-of-standard packets (and the older RTPAD.EXE were more forgiving), or the new RTPAD.EXE cannot understand all the protocol variants and intricacies (as the older versions did). I tried exchanging V8.3 RTPAD.EXE (ident X-10) with a couple of older versions (idents X-8, X-9) and even with the V8.4 one (ident X-10 too, so should be the same as V8.3), to no avail: every one of them ACCVIOs as well. The oldest I tried (X-8) comes from plain vanilla V7.2 (and does not work), but I'm almost sure (I cannot swear on it, though) that RTERM worked fine in V7.2, so I'm stuck: the same image (X-8) was working on V7.2 but it's not in V8.3. I know that testing by exchanging images among different VMS versions is not bulletproof, but considering that I didn't get any error like SHRIDMISMAT and such, I feel confident about thinking that they are compatible. So maybe the problem is somewhere else, probably in some shared library. What else can I do? Is there anyone with the right knowledge (I'm thinking to e.g. Brian Schenkenberger) that can try to track down the bug and at least identify in which part of VMS lies the problem? Or give me some suggestions... This is what happens: | $ set host/app=r xxxxxx | %REM-I-CONNECTION, connection made using RTERM protocol | %SYSTEM-F-ACCVIO, access violation, reason mask=00, virtual address=000052D800008AA4, PC=000052D800008AA4, PS=0000001B | | Improperly handled condition, image exit forced. | Signal arguments: Number = 0000000000000005 | Name = 000000000000000C | 0000000000010000 | 000052D800008AA4 | 000052D800008AA4 | 000000000000001B | | Register dump: | R0 = 0000000000000003 R1 = 0000000000008F50 R2 = 000000000000813A | R3 = 0000000000034804 R4 = 000000007FFCF814 R5 = 0000000000009AEF | R6 = 0000000000000000 R7 = 0000000000000001 R8 = 000000000003481C | R9 = 000000007FF9DDF0 R10 = 000000007FFA4F28 R11 = 000000007FFCDC18 | R12 = 000000007FFCDA98 R13 = 0000000000005170 R14 = 0000000000008E28 | R15 = 0000000000008E28 R16 = 0000000002A83089 R17 = 0000000000200000 | R18 = FFFFFFFF80903360 R19 = 0000000000009ACC R20 = 0000000000000000 | R21 = 00000000000388CB R22 = 000000007AD69A54 R23 = FFFFFFFF801877D0 | R24 = 0000000000000001 R25 = 0000000000000003 R26 = FFFFFFFF8018780C | R27 = 000000007AD69A54 R28 = 0000000000000006 R29 = 000000007AD69A60 | SP = 000000007AD69A30 PC = 000052D800008AA4 PS = 300000000000001B (I can obviously provide other data, such as SDA output from process dump, if needed, or the dump itself in private mail.) Now that there is a TOPS-10 host on HECnet, can some people try at least to trace on which versions it works and on which it does not? Thanks to everyone! :) G.