Abstract: Frequently designers of computer systems have few (if any) convenient means of investigating system per- formance during actual operation. This kind of analy- sis must, of course, take into account user demands and characteristics of the host system's hardware/software complement. Moreover such studies are complicated because they typically involve a large number of variables which, because of their random nature, do not exhibit unique values. The problem is not only to identify criteria which characterize the manner in which the system is used but also to select parameters which are readily measurable. This presentation describes the approaches employed in characterizing and instrumenting the usage and servicing capacity of two operating systems designed for use on Xerox Sigma computer systems. These operating systems are the Batch Time-sharing Monitor (BTM) and the Universal Time-sharing System (UTS). The performance monitors are designed with emphasis on sampling, sorting and ordering of statistical data. Examples of performance monitoring data are presented which were obtained from actual measurements.

Abstract: THE RESULTS OF INSTRUMENTATION DO NOT IN THEMSELVES MAKE FOR IMPROVED UNDERSTANDING OR BETTER PRACTICE. THE EMPHASIS SHOULD BE ON OBSERVATION (WHICH IN ITS BROADER SENSE INCLUDES INSTRUMENTATION) RATHER THAN ON INSTRUMENTATION. THE FACT THAT THE DEGREE OF INSTRUMENT SOPHISTICATION IN MEASURING CERTAIN FACTORS CANNOT REMEDY SOME DEFECTS, IS ILLUSTRATED BY CONSIDERATION OF UNDERGROUND CONSTRUCTION, WHERE THE ENGINEER DEALS WITH MATERIALS HAVING PROPERTIES THAT VARY NOT ONLY IN SPACE BUT ALSO IN TIME. THE MORE COMPLEX THE EQUIPMENT, THE GREATER THE POSSIBILITY OF MALFUNCTION. IT IS SUGGESTED THAT IF IT IS POSSIBLE TO MAKE DIRECT VISUAL OBSERVATION WITH A GRADUATED SCALE, A MICROMETER SHOULD NOT BE USED. SOMETIMES A CHOICE DOES NOT EXIST AND ONLY A SOPHISTICATED SYSTEM WILL SERVE. SOME SUCH SYSTEMS NOW ON THE MARKET HAVE NOT STOOD THE TEST OF EXPERIENCE. IN THE USAGE OF SUCH EQUIPMENT, THE EXPERIMENTAL NATURE OF THE DEVICE MUST BE RECOGNIZED. FIELD OBSERVATIONS PROVIDE A POWERFUL AND SOMETIMES INDISPENSABLE TOOL IN SOIL MECHANICS. IT IS A MATTER OF CONCERN THAT TOO MANY PROGRAMS ARE DETERMINED BY THE INSTRUMENTS TO BE USED RATHER THAN BY THE PROBLEMS TO BE SOLVED AND THAT SOPHISTICATION AND AUTOMATION ARE OFTEN SUBSTITUTED FOR PATIENT PROOF TESTING OF EQUIPMENT UNDER FIELD CONDITIONS.

Abstract: An electronic instrumentation for the measurement of bioelectrical signals in plants is presented. The problems of common mode signal rejection and amplifier bias current are considered. With the instrumentation presented recordings have been made of bioelectrical signals generated in the India rubber tree (Ficus elastica).

Abstract: Operating over a frequency range from audio to ultraviolet, the modern laser may be the most widely applicable active device at the disposal of today's engineer, enabling him to generate, amplify, modulate, transmit, and detect signals at frequencies more than 10000 times higher than was previously possible. Yet despite the almost unlimited potential for new and exotic applications offered by these shorter wavelengths, innovations have not lived up to their rave notices. Reasons for this relative inertia vary according to the application intended but, in general, it can be predicted that progress in the laser art will accelerate with the improvement of laser efficiency, development of auxiliary systems, and an updating of engineering thinking in terms of finding the ``problems'' that lasers can solve. This first article in a series deals with the laser devices themselves?their advantages and their deficiencies?and will summarize what is happening in the laser art today. Other parts, scheduled to appear in future issues of IEEE SPECTRUM, will cover applications in materials processing, instrumentation and measurement, optical communication, medicine, holography, data processing and storage, displays, and safety.

Abstract: Instrumentation developed for studies of path behavior of the green sea turtle and migration movement of polar bear is described. Preliminary results bearing on navigation ability in these species are presented. Both species operate in difficult environments, and the problems faced in the design of electronic instrumentation for these studies are not completely specified at this time. However, the critical factors yet to be understood are primarily related to the behavior of instrumented animals. The data obtained with these experimental techniques are included, first to illustrate the technique and, second to provide initial preliminary results bearing on animal navigation.

Abstract: An analytical investigation is presented of the effect of unmodeled measurement system errors on the accuracy of aircraft stability and control derivatives identified from flight test data. Such error sources include biases, scale factor errors, instrument position errors, misalignments, and instrument dynamics. Two techniques (ensemble analysis and simulated data analysis) are formulated to determine the quantitative variations to the identified parameters resulting from the unmodeled instrumentation errors. The parameter accuracy that would result from flight tests of the F-4C aircraft with typical quality instrumentation is determined using these techniques. It is shown that unmodeled instrument errors can greatly increase the uncertainty in the value of the identified parameters. General recommendations are made of procedures to be followed to insure that the measurement system associated with identifying stability and control derivatives from flight test provides sufficient accuracy.

Abstract: The design and construction of fast logic modules for nuclear instrumentation has always been a costly and time consuming effort. The demands for and on modules have increased considerably; greater quantities with improved performance capabilities are needed. Improved performance and reduced module cost are obtained by using commercially available emitter-coupled logic and a minimal amount of interface circuitry to form compatible functional circuits which can then be combined to create the various modules necessary for nuclear instrumentation. This paper describes the operation of several functional circuits that have been designed at the Lawrence Berkeley Laboratory to effectively utilize the Motorola MECL III line of integrated logic circuits in NIM Standard fast logic modules. The modules process pulses with rise and fall times of approximately 1 ns and can operate at pulse repetition rates in excess of 300 MHz, yet their cost is less than half that of commercially available 200 MHz units.