rbox —
HP98720 “Renaissance” graphics device
  interface
rbox* at intio?
rbox* at dio? scode ?
wsdisplay* at rbox?
This driver is for the HP98720 and 98721 graphics device, also known as the
  Renaissance. This driver has not been tested with all possible combinations of
  frame buffer boards and scan boards installed in the device. The driver merely
  checks for the existence of the device and does minimal setup.
The Renaissance can be configured at either the
    “internal” address (frame buffer address 0x200000, control
    register space address 0x560000) or at an external select code less than 32.
    At the internal address it will be the “preferred” console
    device. The hardware installation manual describes the procedure for setting
    these values.