"UniBone" is a Linux-to-UNIBUS bridge, implemented with a BeagleBone Black micro Linux system.

The board can be plugged into an older DEC PDP-11 machine, it needs a standard quad "SPC" (small peripheral connector) slot.

UniBone can act as Bus master or Bus slave, and is designed to fulfill many roles:

  • simulate a memory card for a running PDP-11. Memory can be pre-filled or saved, so its like core.
  • simulate devices, especially disk or tape. media images are Linux files then.
  • monitor or trace a running UNIBUS (record the bus traffic)
  • stimulate UNIBUS devices, for test or to dump disk/tape media
  • access UNIBUS devices from SimH

As older PDP-11s tend to break often, UniBone is primarily meant to keep machines running by emulating one or more failed subsystems, until repair.

Current status (2018-06-05):

  • All critical mechanisms are working: proof of concept OK.
  • Implemented a simple bus master, can EXAM/DEPOSIT a PDP-11.
  • Implemented a bus slave: a 128KW memory card.


Road map:

  • operate UniBone in a small PDP-11/05 as memory expansion
  • build 2nd prototype
  • implement RK05 disk
  • document
  • layout & build final hardware
  • support device programmers with an API and cross-compile environment
  • tell the community
  • Do similar projects for QBUS and other busses: QBone, OmniBone, MassBone, S100Bone, ...


unibone detail


Title Author
UniBone - Hardware Written by Administrator
UniBone - Software Written by Administrator
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