A High-Scanning-Rate Storage Device for Computer Applications

ABSTRACT

The results of an investigation of the use of photographic techniques for high-scanning-rate digital storage are presented.The most promising technique, that of utilizing a projection system and a rotating mirror, is described in detail. In this system, the binary-digital information recorded on a photographic medium in the form of spots is projected on a rotating mirror by a device similar to a common slide projector. The image reflected from the rotating mirror sweeps past a row of stationary photoelectric transducers and causes the transducers to “read” the stored information.Experiments conducted with a simple slide projector and a rotating mirror resulted in a reading rate of 250,000 cps, with a mirror speed of 3600 rpm and a memory pattern of 110 lines per inch.A system using a memory pattern that is 4 by 4 inches and that contains 16 × 10 6 bits of information, each bit being 0.0005 by 0.002 inch, is proposed. This information would be written in parallel channels, each approximately 40 bits in width and 4 inches in length. Schemes for reading each of the channels repeatedly and for reading the channels successively are discussed. The reading rate should be greater than 1 million words per second.

REFERENCES

• 1: O'NEAL, 1~. D., Photographic Method for Handling Input and Output Data, Annals of the Computation Laboratory of Harvard University, J6(1948), 260-266.
• 2: TY~Ea, A. W., Optical Photographic Storage Techniques, Annals of the Computation Laboratory of Harvard University, t6(1948), 146-150.
• 3: KING, G. W., BROWN, G. W., AND R~DBNOUR, L. N., Photographic Techniques for Information Storage, Proc. IRE, 41, (Oct. 1953), 1421-1428.
• 4: Editor, What's Ncw, Control Engineering, Aug. 1956, 134.
• 5: RY.~N, R. D., A Permanent High Speed Store for Use with Digital Computers, Trans.. IRE, Prof. Group on Electronic Computers, EC-8, (Sept. 1954), 2-5.
• 6: P. A. Hurney, Jr., Combined analogue and digital computing techniques for the solution of differential equations, Papers presented at the February 7-9, 1956, joint ACM-AIEE-IRE western computer conference, February 07-09, 1956, San Francisco, California [doi>10.1145/1455410.1455433]
• 7: Revolutionary Switch for Memory Circuits, Electronic News, ~, 23, (April 8, 1957), 4.
• 8: MI~ZHZLL, A. L., Photoelectric Analog-to-Digital Converters, Electronic Design, 4, (May, 1956), 20-23.
• 9: BAUMANN, D. M. B., Photographic Devices for Semipermanent Digilal 8toraye Requiring High Scanning Rates, S. M. thesis, Dept. of Mech. Engr., Mass. Inst. of Tech., Cambridge, Mass., 1957.
• 10: PaESTON, T., AND THm:~, W. E., The Theory of Light, Macmillan and Company, Ltd., London, 1912.
• 11: SAWYER, D. E., xsv REDXKF.R, R. H., Fast Response Photodiode, paper presented at second annual meeting of IRE Professional Group on Electronic Devices, Washington, D. C. Also in M.I.T. Lincoln Laboratory Group $$ Progress Report, Feb. l, 1957, pp. 6-9.

INDEX TERMS

Primary Classification:
  D. Software
  D.4 OPERATING SYSTEMS

General Terms:
Design, Experimentation, Measurement, Performance, Theory