Ok, I have managed to assemble and link a program! .R MACRO *DEMOFG.OBJ,DEMOFG.LST=DEMOFG.MAC results in the expected listing and object file (I'm glad Gary Kildall modelled CP/M after RT-11!) Then I linked it with .R LINK *DEMOFG.SAV=DEMOFG.OBJ,ODT.OBJ Then I ran it with .R DEMOFG and it ran, popped into ODT which I continued out of and exited 'cuz the background program wasn't running. OK. So we're almost cooking, but it raises some interesting questions: 1) I can compile on the other disk by preceding the names with DX1: in the assmbler line. 2) How can I run a program on DX1: ? If I type .R DX1:PROG it says ?ILL-CMD? 3) Which side of the disk is the directory on? (inner or outer tracks?) The last question relates to the disk problem I'm seeing. My guess is that write precompensation is screwed up on that disk which would explain why it works until it writes the directory. --Chuck