Another early output device was the impact printer, where ink was applied by force onto the paper, much like a typewriter.
Much of the early work focused on geometric forms and on structure, as opposed to content.
The artist, Ben Laposky, used an oscilloscope to manipulate electronic waves that appeared on the small fluorescent screen.
An oscilloscope is a device for displaying the wave shape of an electric signal, commonly used for electrical testing purposes.
In the early 1960s computers were still in their infancy, and access to them was very limited.
Computing technology was heavy and cumbersome, as well as extremely expensive.
This was, in part, due to the restrictive nature of the available output devices, for example, pen plotter drawings tended to be linear, with shading only possible through cross hatching.
The computer would guide the pen or brush across the drawing surface, or, alternatively, could move the paper underneath the pen, according to instructions given by the computer program.
They considered the computer an autonomous machine that would enable them to carry out visual experiments in an objective manner.
Both plotter drawings and early print-outs were mostly black and white, although some artists, such as computer pioneer Frieder Nake, did produce plotter drawings in colour.
Early versions of unix measured system time in 1/60 s intervals.
This meant that a 32-bit unsigned integer could only represent a span of time less than 829 days.