I got a chance to do some work on the UNIX V1 sources this evening. I took the output of my OCR software and with a couple of hours of editing, it successfully assembles with a MACRO11 assembler modified for "as" syntax, with the only exception being that "fpsym" is undefined. It looks like the floating point emulation code is missing. Since this OCR is independent of the other work that has been done, a diff should provide an opportunity to fix any errors in the comments that would not have been caught by the assembler. Is there a place to upload this without a Google account? The assembler listing is about 416K. I wrote much of the bootstrap code a few weeks ago, so it ought to be straightforward to get this up and running under simulation. James Markevitch