Today's printer is the offspring of typewriters and the typesetting industry. The printer has passed through many primitive and frustrating early life forms. In spite of this, printers have populated the earth and evolved many subspecies. Even now, this rapid evolution has not stopped. Daisywheels begot dot matrixes, which begot inkjet printers, which begot laser printers. Daisywheels have died, and laser printers are crowding out dot-matrix and inkjet printers. In circular evolutionary fashion, printers are starting to encroach on one of their ancestral parents' nich the typesetting industry. Desktop publishing is an up-and-coming reality.
Typewriters turned into printers when they were attached to the first main-frame computer. Users punched holes in cards and fed the cards into windows through the wall of the computer room. Inside the computer room, operators manually fed cards into the computer. As the mainframe printer piled up paper, operators ripped the printouts into bundles with the author's name on top, and then pushed the bundles out other windows in the computer room wall. The mainframe printer was an integral part of the whole system's operation. These printers were very expensive, operated at high speeds, and produced poor-quality printouts.
The next evolutionary step was the development of the TeleTYpe (TTY) terminal. Although mostly mechanical, TTY had a built-in printer, and TTY terminals eliminated the pilgrimage to the computer room. As users typed on the keyboard, the characters were sent to the mainframe. The mainframe then sent a copy of the characters back to the TTY terminal. A typist, there-fore, could check whether the character made the round trip successfully. The most important aspect of this developmental stage was the removal of the printer from the mainframe site to the TTY terminals. This move eliminated the tedium of operators manually feeding computer cards and baby-sitting printers. The TTY displayed everything on paper.
The next big change was the development of CRT (Cathode Ray Tube) terminals. CRT terminals are much quicker than the TTY terminals because they have no moving parts. Furthermore, they do not need a printer because all the characters sent and received can be displayed on-screen. The need for paper, therefore, was greatly reduced. The one drawback of a CRT was that printouts still required a trip to a printer or a window in the computer room wall. Initially, TTY terminals were retained as remote mainframe printers.
At the same time that the quality of remote mainframe printers was being improved, microcomputers started to appear. The first true printers hooked directly up to microcomputers and served as remote mainframe printers. The first popular printer, designed exclusively for microcomputers, was manufactured by Centronics. The printer's simplicity and low cost created the first market for a printer dedicated to microcomputers.
Simple printers have their roots in TTYs, which were simple to operate. TTYs had two modes of operation and were attached to a computer or functioned as a typewriter. The button that controlled the terminal's function still is called the on-line/off-line button.
