Throwback 50+ years
/In my lab, before a Digital Equipment Corporation (DEC) PDP8-i with 8k of 12 bit memory, a Teletype, and an AXO8 interface box with 8 channels of a/d conversion (12 bit), 2 channels d/a conversion (10 bit) and 12 (?) digital i/o lines was purchased for $12,800, there were digital logic elements and a MAC panel with plug-in panel connections. The inputs and outputs of the digital logic elements (AND gates, OR gates, Inverters (NOT element), One Shots, Multivibrators, etc.) were wired to the back of the MAC panel. Wires were used to connect the inputs and outputs of the logical elements to form circuits that performed particular functions such as generating an event code that was recorded on one channel of an 8 channel analog tape recorder. The action potentials recorded from a single neuron were preserved on another channel, and other pertinent physiological data on the remaining channels. The wires were the "program" and a different program could be run by removing the panel with the wires and replacing it with another panel with a different set of wires that connected the inputs and outputs of the logical elements in a different manner.
The digital logic components are in the left relay rack. The MAC panel with wires are to the right, under the oscilloscope, and the 8 channel analog tape recorder is to the right of the MAC panel.