I have probably asked this question before, but without the additional information. I am enhancing the code in a program that runs under RSTS/E (or at least the RT-11 RTS under RSTS/E), RT-11, TSX-Plus and RTEM-11 (or at least some sort of RT-11 emulation under RSX-11 which Johnny has described to me before, but which I am not quite sure how to characterize). Quite recently (just yesterday in fact), I attempted to use ODT* again under RT-11. Ever since SD(X).SYS arrived in RT-11 with V05.04, ODT* has no longer been very useful. However, I was rather surprised to find that it not only works quite well, but in addition, does not freeze system jobs. Being in an experimental mood, I also managed to copy ODT.SAV* over to RSTS/E and found to my astonishment that it also works there very well, I presume under the RT-11 RTS under RSTS/E. My question is: How does a user debug a program under the RT-11 RTS under RSTS/E? Is ODT* generally considered the only way? Up until now, I did not even have an answer. And no one else seemed to know either. There is one rather minor difficulty with using ODT* in that I do not have the source for the program that is being enhanced and I must work with just the SAV file. If anyone is interested, I can let them know how I solve that problem as well. In addition, I still do not have any documentation for how RTEM-11 supports RT-11 EMT requests? Can anyone help? Does anyone have access to a running RTEM-11 that I can at least use to perform some tests? Jerome Fine * For those of you who know better, I am actually using the variation of ODT called VDT which does everything that ODT does, but also runs in a multi-terminal environment as well as under the normal single terminal monitors such as the distributed RT11XM.SYS monitors that DEC produces for the binary RT-11 distributions. To my surprise, VDT also runs under VBGEXE, although I actually tried that after running VDT.SAV under the RT-11 RTS under RSTS/E. About the only advantage to using VDT is that SDX.SYS freezes system jobs during a breakpoint while VDT does NOT affect the operation of a system job, i.e. the system job keeps right on running even when VDT is holding the background job at a breakpoint. In my testing situation, this is a big advantage. Of course, the advantage of VDT under RSTS/E is that this seems to be the ONLY way to have debug capability.