LINC-8

Once this is accomplished, 4K memory "wings" can be added in a daisy-chained buss arrangement, which in theory could be expanded out as many as seven times to implement the entire 32K.

As a practical matter, it is always difficult to implement on the "regular" PDP-8, and, in the case of the LINC-8, it becomes necessary to slow down the CPU slightly just to add on the first additional 4K.

It is possible to write a program for a "partial" LINC CPU, meaning using only the hardware that actually exists.

Many operating systems were written for this machine; some were essentially slightly modified versions designed for the original LINC CPU it is partially based on.

If needed, the PDP-8 system can load PROGOFOP as well as a user program primarily LINC-oriented to get at the laboratory peripherals.

This corresponds to a small reserved area at the end of LINC segment 3 in exchange for much greater overall flexibility.

These devices include analog inputs in the forms of knobs and jacks, relays for control of external equipment, LINCtape drives (the predecessor of the DECtape), an oscilloscope-like cathode ray tube under program control, as well as a Teletype Model 33 ASR.

Most of the modifications involve custom highly stripped down plug in modules, which also house the actual knobs hooked to the lowest A-D channels.

The hardware, when enabled, continuously monitors instruction execution until specific conditions are met.

It is small enough to fit in a laboratory environment, provided modest computing power at a low price, and included hardware capabilities necessary to monitor and control experiments.

Few LINC-8 computers were ever built, numbering only in the low hundreds, and so the model is a rare sight today.

As of 2008, a project to emulate the LINC-8 on modern hardware is underway within the Update computer society at Uppsala University.