NLS was designed around a Scientific Data Systems SDS 940 time-sharing computer with an approximately 96 MB storage disk. It could support up to 16 workstations, which were composed of a raster-scan monitor, a three-button mouse, and a device known as a chord keyset. The input of typed text was sent from the keyboard to a specific subsystem that relayed the information along a "bus" to one of two Display Controllers and Display Generators. The inputted text then was sent to a 5-inch cathode ray tube (CRT), which was enclosed by a special cover and a "superimposed" video image was then received by a professional-quality black-and-white TV camera. The TV camera information was then sent to the closed-circuit Camera Control and Patch Panel, and, finally, displayed on each workstation's video monitor.
Development of NLS was more or less finished in late 1968 and was demonstrated to a small crowd of technology specialists in San Francisco on December 8, 1968. It has since been dubbed "The Mother of All Demos" as it demonstrated the important features of NLS in a way never done before. NLS was linked via leased telephone lines to ARC members in Menlo Park, California and the main display of the presentation was on a large 20 foot diagonal projection screen with Douglas Engelbart addressing the audience wearing a headset.
The downfall of NLS, and subsquently, of SRI in general, was its difficult learning curve. NLS was not designed to be easy to learn, it employed the heavy use of program modes, relied on a strict hierarchical structure, did not have a point-and-click interface, and forced the user to have to learn cryptic mnemonic codes to do anything useful with the system. The chord keyset, which complemented the modal nature of NLS, forced the user to learn a 5-bit binary code if they didn't want to use the keyboard. Finally, with the arrival of the ARPA Network at SRI in 1969, the time-sharing technology that seemed practical with a small number of users became impractical over a distributed network; time-sharing was rapidly being replaced by individual minicomputers (and later microcomputers) and workstations. Attempts to port NLS to other hardware, such as the PDP-10 and later on the DEC 20, were successful but did nothing to spread NLS beyond SRI.
Frustrated by the direction of Engelbart's "bootstrapping" crusade, many top SRI researchers left, with many ending up at the famed Xerox PARC, taking the mouse idea with them. SRI sold NLS to Tymshare in 1977 and renamed it Augment, and was, in turn, sold to McDonnell Douglas in the early 1980s. The HyPerform program sold by NDMA Inc. is a descendant of NLS/Augment.
NLS also stands for National Language Support