IBM 740

The IBM 740 CRT Recorder was announced in 1954 and used with the IBM 701, IBM 704, and IBM 709 computers to draw vector graphics images, point by point, on 35 mm photographic film (i.e. microfilm). The 740 film recorder contained digital to analog converters and a 7 inch, high precision, electrostatic CRT. The raster size was 1024 by 1024, but only 256 resolved spots could be displayed on a vertical or horizontal line. Points could be displayed in one of two intensities, and a line could be drawn from a point, vertically or horizontally, to the edge of the display to form an axis.

The 740's CRT used a short persistence P11 phosphor. Film was stored in a magazine that could hold up to 100 feet and could be advanced under computer control. ASA 200 speed film was recommended.

The IBM 780 CRT Display was a monitor that could be attached to the 740 and mirror to an operator what was being drawn on 740's CRT. The 780 had a 21 inch CRT with a long persistence (2 second, nominal) P7 phosphor.

See also

• IBM 2250

References

• IBM 709 Data Processing System, Form A22-6501-0, 1958, p.106ff.

External links

• IBM Archive article about the 740
• CRT Phosphor Characteristics