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6.74 "In a paper presented at the International Symposium on Modern Optics, researchers at the IBM Scientific Centre at Houston, Texas, described how they have programmed a computeran IBM System/360 Model 50-to calculate the interference patterns that would be created if light waves were actually reflected from a real object. Neither the real object nor actual light waves are required to produce holograms with the computer technique. While the initial IBM computer hologram experiments have been restricted to two-dimensional objects for research simplicity, the authors said further work is expected to make possible digital holograms which can be reconconstructed into 3-D pictures. An engineer could then get a 3-D view of a bridge or car body design without actually building the physical object or even drawing it by hand.” (The Computer Bull. 11, No. 2, 159 (Sept. 1967)).

“More recently, firms have experimented with computer-generated holograms for unique data display. NASA's Electronics Research Center in Boston, Mass., is said to be investigating making real-time holograms for such applications as airport display to approaching aircraft.

“A team at IBM's Houston Scientific Research Center has programmed a System/360 Model 50 to create hologram by calculating the necessary interference patterns.

“Thus it may soon be possible to use the computer to create a mathematical model of a device and then translate equations into a three-dimensional hologram of the mathematical model." (Serchuk, 1967, p. 34).

6.75 “Holograms of three dimensional images have been constructed with a computer and reconstructed optically. Digital holograms have been generated by simulating, with a computer, the wave fronts emanating from optical elements, taking into account their geometrical relationship. We have studied in particular the effects of various types of diffuse illumination. Economical calculations of high resolution images have been accomplished using the fast finite Fourier transform algorithm to evaluate the integrals in Kirchoff diffraction theory. We have obtained high resolution three dimensional images with all the holographic properties such as parallax, perspective and redundancy.” (Hirsh et al., 1968, abstract, p. H 104).

“Kinoforms serve for all of the applications of computer-generated holograms, e.g., three-dimensional display, wave conversion, read-only storage, etc. However, kinoforms give a more practical, computationally faster display construction that yields more economical use of the reconstructing energy and that yields only the desired image.

“The principal computational advantage of kinoforms as compared with digital holograms is embodied in the fact that all of the spatial frequency content of the device is used in the formation of the real image; none is required for the separation of the real and conjugate images. There is then at

least a factor of four reduction in the computer time needed to calculate the wavefront pattern necessary for equivalent image quality. Correspondingly there is a reduction in plotting time for the kinoform.

“A further economy is achieved in that no calculations involving a reference beam are necessary. Finally, in the cases of one- and two-dimensional objects only real-number additions are required, once the basic transform is calculated, to determine the wavefront phase for plotting. The corresponding quantity to be plotted for digital holograms is the wavefront intensity which requires multiplication of complex numbers." (Lesem et al., 1969, p. 155).

6.76 "A[n] ... important reason for synthesizing holograms is to create optical wavefronts from objects that do not physically exist. A need to form such a wavefront from a numerically described object occurs whenever the results of a threedimensional investigation, for example, the analysis of an x-ray diffractogram must be displayed in three dimensions." (Brown and Lohmann, 1969, p. 160).

"Scientists, stock brokers, architects, statisticians and many others who use computers may soon have a practical, fast, and inexpensive way of converting memory data into three-dimensional pictures and graphs.

“With a process devised at Bell Telephone Laboratories, it takes only a few seconds of computer time to turn equations, formulas, statistical data and other information into a form suitable for the making of holograms. Viewed under ordinary light, the holograms produce three-dimensional pictures that can display a full 360-degree view of the object shown.

“Holography, which has been called 'lensless photography,' records a subject through the interference of two laser beams on a photographic plate. One beam is aimed directly at the plate, and the other reaches the plate after being transmitted through, or reflected by, the subject being 'photographed.'

"In the BTL method, the original subject exists only as a group of numbers or coordinate points in three dimensions, for example, in the computer's memory. The hologram is made in two steps. First, the computer is programmed to construct a series of two-dimensional pictures, or projections, each showing the 3-D data from a precisely defined unique angle. A microfilm plotter, connected to the computer, produces a microfilm frame for each picture.

“In the second step, a holographic transparency is made. The frames of the microfilm are used as subjects to make very small holograms (1 to 3 mm across), which are positioned sequentially on holographic medium.'

“Thus, a composite hologram is made up of a series of small holograms, each of which is formed with a two-dimensional image. But the composite image appears three-dimensional, and shows a

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and memories . . . will provide significant reductions in cost since the implementation of flexible character recognition equipment involves complex logical functions." (Hobbs, 1966, p. 37).

“Of course, the cost of electronics associated with peripherals will be drastically reduced by LSI. But the promise of LSI is greater than that. Functions that are now handled by mechanical parts will be performed by electronics. More logic will be built into terminals, and I/O devices such as graphic displays, in which the major cost is circuits, will come into more general use." (Hudson, 1968, p. 47).

“This speed power performance requires only modest advances from today's arrays. The board module size is convenient for small memory applications and indicates the method whereby LSI memories will establish the production volume and the impetus for main frame memory applications. The LSI memory being produced for the Air Force by Texas Instruments Incorporated falls into this category.” (Dunn, 1967, p. 598).

"The Air Force contract (with Texas Instruments] has as a specific goal the achievement of at least a tenfold increase in reliability through LSI technology as compared with present-day integrated circuits.” (Petritz, 1967, p. 85).

“Impetus for continued development in microelectronics has stemmed from changing motivations. Major emphasis was originally placed on size reduction. Later, reliability was a primary objective. Today, development of new materials and processes point toward effort to reduce cost as well as to further increase reliability and to decrease weight, cube, and power.” (Walter et al., 1968, p. 49).

p. “This (LSI) technology promises major impact in many areas of electronics. A few of these are:

1. Lower cost data processing systems. 2. Higher reliability processing systems. 3. More powerful processing systems. 4. Incorporation of software into hardware,

with subsequent simplification of hardware."

(Petritz, 1966, p. 84). “Computer systems built with integrated circuits have higher reliability than discrete-component machines. This improved reliability is due to two factors: (1) the silicon chip has a higher reliability than the sum of the discrete components it replaces, and (2) the high density packaging

( significantly reduces the number of pluggable contracts in the system.” (Henle and Hill, 1966, p. 1854).

6.85 “One of the most interesting and significant paradoxes of the new technology is the apparent reconciliation of a desire to achieve high speed and low cost. The parameters which yield high speed, i.e., low parasitics, small device geometry, also yield lowest ultimate production cost in silicon integrated circuits.” (Howe, 1965, p. 506).

6.86 “Some examples of functional expansion we would naturally consider are as follows. In the

central processor LSI might be used to carry out more micro-operations per instruction; address more operands per instruction; control more levels of look-ahead; and provide both repetition and more variety in the types of functions to be executed. In system control, LSI might provide greater system availability through error detection, error correction, instruction retry, reconfiguration to bypass faulty units, and fault diagnosis; more sophisticated interrupt facilities; more levels of memory protection; and concurrent access to independent memory units within more complex program constraints. In system memory, LSI might provide additional fast local memory for operands and addresses; improved address transformation capability; content-addressable memory;

and special fast program status tables. In system input-output, LSI might provide more channels; improved interlacing of concurrent input-output operations with automatic memory protection features, and more sophisticated pre- and postprocessing of data and instructions to relieve the central processor of these tasks.” (Smith and Notz, 1967, p. 88).

“LSI has an inherent functional advantage over magnetics in associative applications, namely that fast bit-parallel searches can be achieved. The main drawback of magnetic associative memories, even in those applications which require relatively simple match-logic per word, is that imperfect cancellation of analog sense signals and other noise effects give rise to a low signal-to-noise ratio and thereby limit the technology to essentially bit-serial operation. Thus, the more nearly binary signals available from semiconductor associative devices seem to provide a unique advantage over magnetics which is not strongly evident in comparisons of the two technologies over other categories of memory.” (Conway and Spandorfer, 1968, p. 842).

"Content Addressable Memories: As the semiconductor manufacturer learns to produce more and more components on a single silicon chip, reasonably sized content-addressable memories may become feasible. Memories of this type, available on a large scale, should permit significant changes in the machine language of the computer, and possibly provide simplification in the design of such software as operating systems and compilers." (Graham, 1969, p. 104).

6.87 “Revolutionary advances, if they come, must come by the exploitation of the high degree of parallelism that the use of integrated circuits will make possible.” (Wilkes, 1968, p. 7).

“One area in which I feel that we must pin our hopes on a high degree of parallelism is that of pattern recognition in two dimensions. Present-day computers are woefully inefficient in this area. (Wilkes, 1968, p. 7).

6.88 “The recent advance from discrete transistor circuits to integrated circuits is about to be

overshadowed by an even greater jump to LSI circuitry. This new jump will result in 100-gate and then 1000-gate circuit modules which are little larger in size or higher in cost than the present four-gate integrated circuit modules.” (Savitt et al., 1967, p. 87).

6.89 "Discrete components have given way to integrated circuits based on conventional etched circuit boards. This fabrication technique is in turn giving way to large scale integration (LSI), in which sheets of logic elements are produced as a unit." (Pyke, 1967, p. 161).

“The initial results suggest the possibility of fabricating, in one step, a complete integrated circuit with all the passive elements. Such a process would start with a metallized substrate and would use a programmable laser and work stage. Complete laser fabrication of hybrid circuits will require a process in which a metal film is removed selectively, exposing a different film. For example such a process may be necessary in order to remove the conductor and expose the resistor film.

“In the present tantalum-chrome-gold technology such a selective removal of the gold presents substantial difficulties because the reflectivity of the gold is much greater than that of the tantalum nitride. It is quite probable, however, that some combination of films will be found for which the upper film can be removed from the resistor without damaging it." (Cohen et al., 1968, p. 402).

6.90 "Integrated circuits (more importantly, large scale integration (LSI) which involves numerous integrated circuits tied together on the same chip) offer the best promise from the standpoint of size, reliability and cost [for scratch-pad memories).” (Gross, 1967, p. 5).

6.91 "Of all the potential applications of largescale integration, new memory techniques are the most startling. Ferrite core memories have just about reached their limit in terms of access speeds required for internal scratchpads. Magneticthin films, while fast enough, are too costly. Studies show that because of LSI, semiconductor memories are less costly than any other approach for speeds from 25 to 200 nanoseconds and for capacities up to 20,000 bits - just the range required by scratchpads." (Hudson, 1968, p. 41).

6.92 “In addition to being used for circuitry, LSI techniques apply to the construction of memories, since some of the new memory elements mentioned above can be fabricated using the micro-construction techniques. The possibility also comes to mind of fabricating both the comparison circuitry and the memory cells of a contentaddressable memory into a single unit. Thus the development of large-scale integration holds considerable promise for improving computer hardware." (Van Dam and Michener, 1967, p. 210).

6.93 “In view of the economy that should accompany widespread use of LSI, it may become less expensive to use LSI logic elements as main

memory elements, at least for some portion of primary storage. Even today some systems have scratchpad memories constructed of machine logic elements, so that the fast processor logic is not held back by the slower memory capability.” (Pyke, 1967, p. 161).

6.94 “LSI memories show considerable potential in the range of several hundred nanoseconds down to several tens of nanoseconds. In contrast with logic, LSI memory is ideally suited to exploit the advantages and liabilities of large chips: partitioning is straightforward and flexible, a high circuit density can be obtained with a manageable number of input-output pads, and the major economic barriers of part numbers and volume which confront LSI logic are considerably lower. Small-scale memory cell chips have already

superseded film memories in the fast scratchpad arena; the depth of penetration into the mainframe is the major unresolved question." (Conway and Spandorfer, 1968, p. 837).

6.95 "As technological advances are made, the planar technology permits us to pack more and more bits on a single substrate thus reducing the interconnection problem and simplifying the total memory packaging job. This integration will reflect in the long run on product cost and product reliability." (Simkins, 1967, p. 594).

6.96 “The new technology has a number of problems whose solution can be facilitated by arranging the circuitry on these arrays in a 'cellular form that is, in a two-dimensional iterative pattern with mainly local intercell connections that offers such advantages as extra-high packing density, ease of fabrication, simplified testing and diagnosis, ease of circuit and logical design, the possibility of bypassing faulty cells, and particularly an unusually high flexibility in function and performance." (Kautz et al., 1968, p. 443).

6.97 "LSI offers improvements in cost and reliability over discrete circuits and older integrated circuits. Improvement in reliability is due to the reduction of both the size and the number of necessary connections. Reductions in cost due largely to lower-cost batch-fabrication techniques. One problem in fabrication is the increased repercussion of a single production defect, necessitating the discarding of an entire integrated component if defective instead of merely a single transistor or diode. This problem is attacked by a technique called discretionary wiring; a computer tests for defective cells in a redundantly constructed integrated array and selects, for the good cells, an interconnection pattern that yields the proper function.” (Van Dam and Michener, 1967, p. 210).

"Since packaging and interconnections major factors in the cost of an integrated circuit, the cost potentials . . . can be achieved only by batch fabricating large arrays of interconnected circuits in a single package. This raises many difficult and conflicting questions, such as packag.

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