IBSYS Fortran II runs on a SIMH-based simulator

An upcoming release of Bob Supnik’s SIMH (Computer History Simulation system) will include IBM 704/709/7090/7094 simulation provided by Rich Cornwell. Rich has been very busy lately: implementing and debugging the simulations of the CPU, channels, controllers, and devices; tracking down and transcribing source code for diagnostics; and figuring out how to rebuild and run various diagnostics, SHARE, IBSYS, and CTSS code. He’s had great luck with the IBSYS distribution from Paul Pierce; in particular, he was able to get the code compiled by the Fortran II compiler to execute. It turns out the Fortran II compiler writes out intermediate files to tape as individual records not followed by the customary tape mark; it was necessary to tweak the simulator to handle this the way the original hardware did. Rich notes that Bob Supnik, who is also working on a 7094 simulator, was the first person to discover this. (Rich says Bob will include both Rich’s and his own 7xxx simulators in SIMH since Bob’s is specifically optimized for running CTSS while Rich’s is aimed more toward IBSYS and older 704/709 software.)

Rich’s enthusiasm inspired me to finally obtain a copy of the Smithsonian’s Fortran II listing — this is a version for the IBM 704, which does not have I/O channel — it is the machine for which the original Fortran I compiler was written. Rich is in the process of recreating the assembly language source code from which this listing was generated. He’s doing this by hand, because the quality of OCR is not high enough.

Rich has many related projects in mind, and welcomes others who would like to join in: transcribing/proofreading diagnostics and the 704 Fortran II listing, working on some remaining IBSYS language processors, getting the Lisp 1.5 interpreter to run, etc. His home page (yes, kites!) has an EMail link for getting in touch with him, or contact me and I’ll put you in touch with him.