Direct-View Storage Tube

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Tektronix 4014, an early DVST-based graphics-capable terminal

The Direct-View Storage Tube (DVST) or direct addressing tube is a type of display screen that was developed in the late 1960s. Unlike traditional vector screens, DVSTs were able to display a graphic without the need for periodic redrawing.

Technology and meaning

The DVST is based on the cathode ray tube , but complements it with a fine metal grid that has been coated with a dielectric . It serves as a storage device and is located behind the fluorescent screen. The primary electron gun paints the picture by pushing electrons out of the storage device, leaving a pattern of positive charges. A second electron gun (flood gun) emits a continuous stream of low-energy electrons, which are attracted to the storage device and only pass through the positively charged areas to finally hit the fluorescent screen. Once an image has been drawn, it remains visible on the screen for several minutes until it fades or the storage device is erased by applying voltage.

The first terminals with storage tubes were the ARDS terminal from Computer Displays and the 400 series from Computek , both of which were introduced around 1968. They used the 6 × 8 inch Tektronix 611 storage tube and cost $ 12,000 to $ 15,000. Tektronix then brought out its own terminals with the T4002A, which cost around $ 9,000, followed by the $ 4,000 4010. With the introduction of the 4010, Tektronix dominated the storage tube market and thus a large part of the computer graphics market. DVSTs gave tens of thousands of users access to computer graphics because previous graphics terminals had hardware costs of $ 50,000 to $ 200,000.

literature

  • Jack Belzer et al: Encyclopedia of Computer Science and Technology, Vol. 8, p. 466. Dekker, New York 1977, ISBN 0-8247-2258-2
  • Carl Machover: Four Decades of Computer Graphics. IEEE Computer Graphics and Applications 14, 6 (November 1994): 14-19, here p. 14 f., ISSN  0272-1716
  • William Newman, Robert Sproull: Principles of Interactive Computer Graphics, pp. 15-16, 75. McGraw-Hill, New York 1973, ISBN 0-07-046337-9