The LINC-8 was a computer produced by DEC for use in laboratory settings; it included both a PDP-8 (the original model's CPU) and a LINC computer, which shared access to the PDP-8's main memory (the LINC acted as a DMA peripheral to the PDP-8, using the PDP-8 data break mechanism). A combined front panel allowed control of both CPUs.
Like the LINC, it included a video display (512x512 pixels resolution, but not a bit-mapped display), analog inputs, and LINC tape drives (all attached to the LINC); it could also include any of the standard PDP-8 peripherals (attached to the PDP-8).
Special interrupt-driven code ('PROGOFOP' - 'program of operation') in the PDP-8 allowed code running in the LINC access to PDP-8 resources; the PDP-8 likewise had access to the resources of the LINC (e.g. the display). When the PDP-8 was in control, the LINC was halted until the PDP-8 wanted something done, whereupon an interrupt started the LINC running, to perform the desired action.
It was later replaced as a product for DEC by the PDP-12, which had the same functionality in a more integrated form.