Linear video editing is the process of selecting, arranging and modifying the images and sound recorded on videotape whether captured by a video camera, generated from a computer graphics program or recorded in a studio. Until the advent of computer-based non-linear editing in the early 1990s "linear video editing" was simply called “video editing.”
Actual live television is still basically produced in the same manner as it was in the 1950s (although transformed by myriad technical advances). However, the only way of airing the same shows again before videotape was introduced was by filming shows using a kinescope (essentially, a video monitor paired with a movie camera). However, kinescopes (the films of television shows) suffered from various sorts of picture degradation, from image distortion and apparent scan lines to artifacts in contrast and loss of detail. Also, kinescopes had to be processed and printed in a film laboratory, making them unreliable for broadcasts delayed for different time zones.
So, the primary motivation for the development of videotape was as a short or long-term archival medium. Only after a series of technical advances spanning decades did videotape editing finally become a viable production tool, up to par with film editing.
The first widely accepted videotape in the United States was two inches wide and travelled at 15 inches per second. To gain enough head-to-tape speed, four video recording and playback heads were spun on a head wheel across most of the two-inch width of the tape. (Audio and synchronization tracks were recorded along the sides of the tape with stationary heads.) This system was known as Quad, for quadruplex recording. See 2 inch Quadruplex videotape.
The resulting video tracks were slightly less than a ninety-degree angle (considering the vector addition of high-speed spinning heads tracing across the 15 inches per second forward motion of the tape).
Originally videotape was edited by physically...