Hi Graham Attached is what I found over the weekend. It consists of over 90% of the compiler. The structure of the original is 1. the main entry point and overall controller: DLIB.HDR Ocode.hdr **MastXX.hdr (different versions, the one I have may not be the latest) **MastXX.bpl 2. the parameter reading and parsing, file opening &c Setup.bpl 3. Coral to AE tree parser Cosyn.hdr **CosynX.bpl 4. AE tree to Ocode Cotan.hdr **CotanX.bpl The ones annottated ** are what I found. So it's mostly the headers that are missing, and I guess they could be reconstructed. But there is more stuff to search, so stay tuned. 5. And as a bonus, my narrative description of Ocode as extended for Coral-66. Note that the code files should be read with Wordpad or something sensible. *They cannot be properly formatted under Microsoft Word*, because Word sets tab stops in terms of centimeters, not spaces. I threw another Microsoft homicidal rage fit on discovering this! Yours Robert (See attached file: Mast7c.hdr) (See attached file: Mast7c.bpl) (See attached file: Cosyn.bpl) (See attached file: Cotan.bpl) (See attached file: Ocode Machine)