The PDP-11/23-PLUS computer is based on the F11 chipset. The F11 chip is a 40 pin carrier with two chips which contains the data path and the microcode. There is an optional chip that implements the MMU. The MMU allows the F11 to address up to 4 Mbyte. As a bus it uses the QBUS.
This particular machine has an RL02 and an RL01 drive. The RL02 can hod 10,4 Mbyte and the capacity of the RL01 is 5.2 MByte.
This PDP-11/23-PLUS was donated by a computer club in Jönköping. They had gotten it from Linköping, probably the university. According to the donors this computer had been used by Håkan Lans when working with Datacolor and the famous color graphics patent. According to this article Håkan used a PDP-11 when demonstrating the capabilities of the Datacolor unit to people from Digital Equipment. And sure would the Datacolor fit into the empty space below the disk drive!
It would be interesting to investigate if there would be any cables and connectors inside the computer that would fit a Datacolor unit. Does anyone have some valuable information regarding this?