# Papers on Simulation and Historic Systems

These papers were written to present the rationale for SIMH, to document SIMH, or to document relatively obscure architectural or implementation details in historic systems.

- "Preserving Computing's Past: Restoration and Simulation", by Max Burnet and Bob Supnik, from the Digital Technical Journal, Volume 8, Number 3, 1996 (PDF)
- "SIMH: Forward Into The Past", a presentation to the Vintage Computer Festival East, 16-Jul-2004 (PDF)
- "Writing a Simulator for the SIMH System", by Bob Supnik (PDF)
- "Adding an I/O Device to a SIMH Virtual Machine", by Bob Supnik (PDF)
- "A Revised I/O Simulation for the HP 21xx/1000", by J. David Bryan (PDF)
- "The SIMH Breakpoint System", by Bob Supnik (PDF)
- "SIMH Magtape Representation and Handling", by Bob Supnik (PDF)
- "Architectural Evolution in DEC's 18b Computers", by Bob Supnik (PDF)
- "Decoding the H316/H516 'Generic A' Instructions", by Bob Supnik (PDF)
- "Unearthing the PDP-15 Operating Systems", by Bob Supnik (PDF)
- "PDP-11 Interrupts: Variations on a Theme", by Bob Supnik (PDF)
- "Bug, Feature, or Code Rot? Adventures in O/S Debugging", by Bob Supnik (PDF)
- "A Massbus Mystery, or, Why Primary Sources Matter, Even In Computer History", by Bob Supnik - documenting the oldest extant bug in VAX/VMS (PDF)
- "The Case Of The Missing PLA Term, or, Microcode Bugs I Have Known", by Bob Supnik (PDF)
- New! "How the VAX Lost Its POLY" (PDF)
- "HP's IOP Implementations: 2100 vs 21MX", by Bob Supnik (PDF)
- "CTSS Hardware", by Bob Supnik (PDF)
- "Technical Notes on DECsys", by Bob Supnik (PDF)
- "What was the PDP-X?", by Bob Supnik (PDF)
- "Card Readers for DEC's 18b Systems", by Bob Supnik (PDF)
- "VAX Processor Chart", by Bob Supnik (text)
- Three late 1980's presentations on the design of VLSI VAXen, by Bob Supnik:
  1. "VLSI VAX Micro-Architecture" (PDF)
  2. "Microcoding Considered as a Fine Art" (PDF)
  3. "CVAX and Rigel: The Development Process" (PDF)

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Updated 24-Sep-2011 by Bob Supnik (simh AT trailing-edge DOT com - anti-spam encoded)