specifies form length and the form line where printing on a new page is to begin so that paper of various sizes can be used. The overstrike capability of the printer can be used to generate a wide range of grey-scale equivalents. Many images have been scanned, converted to text and therefore can be reproduced on the 1403, most notably the Mona Lisa. These are noisy machines, especially when the cover is raised. It is possible to create text that uses the timing of the print hammers to generate desired frequencies and thus play recognizable music when that text is printed. History Prior to the introduction of the model 1403, IBM printers utilized technology originally developed for their line of accounting machines. Models 402 and 405 use type bars. These are vertical bars, one for each print position. Each bar is one character wide with either the entire alphabet, including numerals and symbols, or just numerals & symbols only, molded into the front surface, in a single column. In printing, each bar is raised up until the correct character for that print position is opposite the paper, whereupon the bar is pushed toward the paper, so that the correct numeral or letter pressed against the ribbon, striking the paper much the way type slugs leave an impression on paper in a standard typewriter. This action is relatively slow, as it took time for each bar to be brought up into the correct position and then drop back down in preparation to print the next line. In the model 407, each type bar is replaced with a type wheel, with the characters along the outside edge. To print, each wheel is rotated to the correct character position, then the entire wheel is pushed forward to strike the paper. This action is somewhat faster because the wheels are less massive than the bars and can be positioned more rapidly, allowing printing at up to 150 lines per minute. Although this is slow by later printing standards, the speed at which electromechanical accounting machines can read punched cards and perform their basic arithmetic functions means that no faster printing speeds are needed. The IBM 1132 was the last printer manufactured by IBM to use this technology. When faster computers were developed, however, the speed of card reading, magnetic tape, and early disk drives, along with newer high speed transistorized circuits, means that processing