IBM 740
| Industry | Computer hardware |
|---|---|
| Founded | 1954 |
| Products | Vector graphics recorder for microfilm |
The IBM 740 CRT Recorder, launched in 1954, was engineered to operate alongside the IBM 701, IBM 704, and IBM 709 computer models, enabling the creation of vector graphics on 35 mm photographic film (microfilm). It incorporated digital-to-analog conversion technology and utilized a highly accurate 7-inch electrostatic CRT featuring a raster resolution of 1,024 by 1,024 pixels, with a maximum of 256 distinguishable spots per line. The device was capable of rendering points in two brightness levels, while lines could be drawn either vertically or horizontally from these points to construct axes.
Each point shown on the display was represented by a 36-bit data word: 10 bits designated for the X coordinate, another 10 for the Y coordinate, and 3 control bits managing intensity and axis line drawing. Activating both axis control bits simultaneously resulted in a line drawn at a 45-degree angle.
The CRT employed short-persistence P11 phosphor material. Film used was ASA 200-speed 35 mm stock, housed in magazines with lengths up to 100 feet; the advancement of this film was regulated by the connected computer system.
Complementing the recorder, the IBM 780 CRT Display functioned as a monitor linked to the IBM 740, allowing operators to observe real-time images during production. This display incorporated a larger 21-inch CRT equipped with longer-persistence P7 phosphor, which had an approximate persistence duration of two seconds.
See also
References
- IBM 709 Data Processing System, Form A22-6501-0, 1958, p. 106ff.