Search

The article focuses on DigitalDesk, which is a real physical desk where one can stack papers, lay out their favorite pencils and markers, and leave coffee cup, but it is enhanced to provide some characteristics of an electronic workstation. A computer display is projected onto the desk, and video cameras pointed down at the desk feed an image-processing system that can sense what the user is doing. Three important characteristics of DigitalDesk are, it projects electronic images down onto the desk and onto paper documents, it responds to interaction with pens or bare fingers and it can read paper documents placed on the desk. The DigitalDesk provides a computer-augmented environment in which paper gains electronic properties that allow it to overcome some of its physical limitations. The calculator is a simple and familiar application that can benefit from the DigitalDesk. It allows people to place ordinary paper documents on the desk and simply point at a printed number to enter it into the calculator.

Invites several research papers for the forthcoming conferences related to the computing systems.

The effective operation of free enterprise in creating the envisioned information service industry is dependent upon three accomplishments: (1) the restructuring of our information processing industry so that a clear division of costs is mode among computing, communications, and the development of information services; (2) the wide use of multiaccess system concepts so that information services may share in the use of computer installations and so that the cost of their construction is reasonable; and (3) the development of public, message-switched communications services so that adequate provisions are made for Information security. [ABSTRACT FROM AUTHOR]

This article focuses on a conference on "Recent Advances in Computer Simulation Modeling and Statistical Analysis" that was held on April 21-22, 1980 at Columbia University. This conference was organized and chaired by the Guest Editor under the sponsorship of the Special Interest Committee on Simulation of the New York City Chapter of ACM. The first paper develops a unifying approach and a set of definitions to the time and space relationships in simulation modeling. The second and third papers are concerned with the acceptability of simulation models. The first of these two papers presents a framework of concepts and criteria for assessing the acceptability of simulation studies. The other paper presents a methodology for performing a cost-risk analysis in the statistical validation of simulation models of real and observable systems. The fourth paper explores the possibility of using a network of microprocessors for executing simulation models.

The article presents information on the proposed American Standard, "Eleven-Sixteenths Inch Perforated Paper Tape." This standard covers the physical dimensions of the paper tape and its perforations. This standard is for perforated paper tape with fully punched round holes. The punched tape shall have an overall width of 0.686 inch plus or minus 0.003 inch after the tape has been conditioned to within 69.5 degrees F to 76.5 degrees F and 48 percent to 52 percent relative humidity for a period of 24 hours. The tape shall be used for recording up to five levels of information across the tape. The feed holes in the tape shall be fully punched and round with a diameter of 0.046 inch plus 0.002 minus 0.001 inch. All holes punched in the tape shall nominally center on the true intersection of longitudinal and perpendicular transverse center lines spaced 0.100 inch apart. Tolerances on locations of code holes in any one transverse row, relative to the center lines of the feed hole in that row, shall be plus or minus 0.002 inch in the transverse direction and plus or minus 0.003 inch in the longitudinal direction.

The article discusses the factors that affect the sharing of research artifacts relating to computer systems according to the authors. Topics covered include the importance of sharing research artifacts for repeatability and benefaction, the research studies the evaluated the willingness of computer science researchers in sharing code and data, and details relating to the three measures of weak repeatability determined by the authors.

In this paper, we study the problem of estimating the state of a switched linear system (SLS), when the observation of the system is subject to communication constraints. We introduce the concept of worst-case topological entropy of such systems, and we show that this quantity is equal to the minimal data rate (number of bits per second) required for the state estimation of the system under arbitrary switching. Furthermore, we provide a closed-form expression for the worst-case topological entropy of switched linear systems, showing that its evaluation reduces to the computation of the joint spectral radius (JSR) of some lifted switched linear system obtained from the original one by using tools from multilinear algebra, and thus can benefit from well-established algorithms for the stability analysis of switched linear systems. Finally, drawing on this expression, we describe a practical coder-decoder that estimates the state of the system and operates at a data rate arbitrarily close to the worst-case topological entropy. [ABSTRACT FROM AUTHOR]

The article discusses various issues related to academic computer science research. Topics include debates on software-development methodology in relation to independent faults, a debate on the evaluation of file system performance, and the use of software-based attestation (SWATT) as a protocol for checking memory images from remote systems.

Discusses some of the thinking and philosophy behind changes in the communications of the journal of "Association for Computing Machines." Logistical and administrative reasons for the intended changes; Purposes and goals of the periodical; Technical papers relevant to the computer industry that are sought by the periodical.

The article informs about some activities of the Association for Computing Machinery (ACM). The ACM's Washington D.C. Chapter's 1973 Technical Symposium will take place at the National Bureau of Standards, Oaithersburg, Maryland, on June 21. Program Chairman is Helmut E. Thiess. The article also informs that the 4th Annual Symposium of the ACM Special Interest Group on Computer Systems Installation Management is scheduled for October 18-19 in Las Cruces, New Mexico. Papers are invited on the following topics: security; virtual systems evaluation; data entry systems-COM; personnel evaluation, measurement, and development; nonprofessional status of data processing personnel; job estimation; etc. The American Society of Indexers will hold its Second Annual All-Day Meeting on Saturday, April 28, at the Graduate Center of the City University of New York. Editors, indexers, librarians and index users will participate in forums and speeches concerned with "Index Traps and Pitfalls: Human Generated/Computer Generated." Three speakers for the morning session include Jessica L. Harris, a professor.

The article reports on certain upcoming conferences, exhibitions, symposiums, and other events related to computing machinery. The Association for Computing Machinery (ACM) Southwest Region will sponsor a meeting on the "Philosophical, Moral, and Ethical Problems of the Computer Scientist in the Computerized Society." In addition to contributed papers by ACM members in the Southwest Region, the program will include special presentations. Donn B. Parker, ACM secretary, will speak on the New ACM Code of Professional Ethics. The Computing Center of the State University of New York at Stony Brook, New York, and the Long Island Chapter of the Association for Computing Machinery are jointly sponsoring the Third Annual Stony Brook Conference on "Advances in Computing" to be held at Stony Brook on June 9, 1967. The International Business Machines Corp. is providing financial assistance for the conference. "Spectrum of Data Processing" is the title of a one-day technical symposium to be held on May 26, 1967, that will be sponsored by the San Diego, California, chapter of the Association for Computing Machinery.

The article outlines the professional activities of the Association of Computing Machinery (ACM). The ACM SIGUCCS Users Conference XII is planned for November 11-14, 1984 in Reno, Nevada. ACM SIGMETRICS Conference on Measurement and Modeling of Computer Systems will be held in Boston, Massachusetts on August 2-24, 1984. The 13th Annual Conference on Parallel Processing will be held on August 21-24, 1984 in Bellaire, Michigan. The Third International Conference on Systems Documentation will be held on May 16-18, 1984 in Mexico City.

The article offers information on several conferences related to Association for Computing Machinery (ACM) to be held in 2102 including fourth annual Conference on the Management of Data in San Jose, California on May 14-16, International Computing Symposium (ICS) in Antibes, France on June 2-4, and Annual Symposium on Theory of Computing in Albuquerque, New Mexico on May 5-7.

This article offers information on the Computing Practices section of the magazine "Communications of the ACM." The section focuses on articles with a message about general ideas and techniques that can be transferred from one place to another. Instead of technical papers, the section concentrates on discussions of how, what, why and when to use the computing methods and systems. Topics that cover areas of interest to readers of the section include improvement of the systems design process, future of computing, and implication of new theory to application systems.

A calendar of events for the Association for Computing Machinery from August 1973 to November 1974 is presented. The Symposium on Principles of Programming Languages to be held in Boston, Massachusetts on October 1-3, 1973. The 4th Symposium on Programming Languages Principles will be held in New York on October 15-17, 1973. The 6th National American Society of Civil Engineers Conference on Electronic Computation will be held in Atlanta, Georgia on August 7-9, 1974.

The article presents information on various meetings to be held in the field of computing in 1971. The Southeastern Region of the Association for Computing Machinery (ACM) is holding its Tenth Annual Conference in Mobile, Alabama on June 19, 2005 at the Admiral Semmes Hotel. The conference is being chaired by Ted E. Turner. The Washington Chapter of the ACM will hold its Tenth Annual Technical Symposium on June 24, 2005 at the National Bureau of Standards. The one-day symposium will consist of panel discussions and papers reviewing ten years of growth and change in the computing industry and looking into the future. The sixth annual ACM Urban Symposium will be held on October 29, 1971, at the New York Hilton Hotel. Sponsored by the New York Metropolitan Chapters of ACM, this Symposium brings together interested professionals from the computing field and from the urban problem areas, and provides a forum for the exchange of ideas, experiences, and information. The Technical Committee on Computer Architecture and the Midwest Area Committee of the IEEE Computer Society are co-Sponsoring a Workshop on Modular Computer Systems.

A comprehensive system for transformational grammar has been designed and implemented on the IBM 360/67 computer. The system deals with the transformational model of syntax, along the lines of Chomsky's Aspects of the Theory of Syntax. The major innovations include a full, formal description of the syntax of a transformational grammar, a directed random phrase structure generator, a lexical insertion algorithm, an extended definition of analysis, and simple problem-oriented programming language in which the algorithm for application of transformations can be expressed. In this paper we present the system as a whole, first discussing the general attitudes underlying the development of the system, then outlining the system and discussing its more important special features. References are given to papers which consider some particular aspect of the system in detail. [ABSTRACT FROM AUTHOR]

Errors in dynamic random access memory (DRAM) are a common form of hardware failure in modern compute clusters. Failures are costly both in terms of hardware replacement costs and service disruption. While a large body of work exists on DRAM in laboratory conditions, little has been reported on real DRAM failures in large production clusters. In this paper, we analyze measurements of memory errors in a large fleet of commodity servers over a period of 2.5 years. The collected data covers multiple vendors, DRAM capacities and technologies, and comprises many millions of dual in-line memory module (DIMM) days. The goal of this paper is to answer questions such as the following: How common are memory errors in practice? What are their statistical properties? How are they affected by external factors, such as temperature and utilization, and by chipspecific factors, such as chip density, memory technology, and DIMM age? We find that DRAM error behavior in the field differs in many key aspects from commonly held assumptions. For example, we observe DRAM error rates that are orders of magnitude higher than previously reported, with 25,000- 70,000 errors per billion device hours per Mb and more than 8% of DIMMs affected by errors per year. We provide strong evidence that memory errors are dominated by hard errors, rather than soft errors, which previous work suspects to be the dominant error mode. We find that temperature, known to strongly impact DIMM error rates in lab conditions, has a surprisingly small effect on error behavior in the field, when taking all other factors into account. Finally, unlike commonly feared, we do not observe any indication that newer generations of DIMMs have worse error behavior. [ABSTRACT FROM AUTHOR]

Monitoring and troubleshooting distributed systems are notoriously difficult; potential problems are complex, varied, and unpredictable. The monitoring and diagnosis tools commonly used today—logs, counters, and metrics—have two important limitations: what gets recorded is defined a priori, and the information is recorded in a component- or machine-centric way, making it extremely hard to correlate events that cross these boundaries. This paper presents Pivot Tracing, a monitoring framework for distributed systems that addresses both limitations by combining dynamic instrumentation with a novel relational operator: the happened-before join. Pivot Tracing gives users, at runtime, the ability to define arbitrary metrics at one point of the system, while being able to select, filter, and group by events meaningful at other parts of the system, even when crossing component or machine boundaries. Pivot Tracing does not correlate cross-component events using expensive global aggregations, nor does it perform offline analysis. Instead, Pivot Tracing directly correlates events as they happen by piggybacking metadata alongside requests as they execute. This gives Pivot Tracing low runtime overhead—less than 1% for many cross-component monitoring queries. [ABSTRACT FROM AUTHOR]

This article focuses on conferences related to computer systems. The 1981 Winter Simulation Conference to be held on December 9-11 in Atlanta, Georgia, is to feature papers, panel discussions, and tutorials on discrete and combined (Discrete/Continuous) simulation modeling; The 15th Annual Simulation Symposium is planned for March 17-19, 1982 in Tampa, Florida; The Fifteenth Hawaii International Conference on System Sciences, Honolulu, January 6-8. 1982, is to cover developments in theory or practice in the areas of computer software and hardware and advanced systems applications; The National Educational Computing Conference 81 is set for June 17-19 at North Texas State University in Denton, Texas; An International Conference on Systems Methodology, organized by the Society for General Systems Research and sponsored by the International Federation for Systems Research, is planned for January 5-9, 1982, in Washington D.C.

The article offers information on several conferences and call for papers including the 1977 Association for Computing Machinery (ACM) Computer Science Conference on January 31-February 2, fifth annual Symposium on the Simulation of Computer System in Gaithersbug, Maryland on August 9-11, 1977, and the annual Simulation Symposium in Tampa, Florida on March 16-18, 1977.

The article presents a calendar of events about the computer industry. The "1967 Spring Joint Committee Conference," which will be held on April 18-20, 1967 in Atlantic City, New Jersey invites papers to be presented during the conference. The American Documentation Institute will hold a convention on October 3-7, 1967 in Santa Monica, California. The International Federation of Information Processing Societies will hold its "1968 Congress" on August 5-10, 1968 in Edinburgh, Scotland.

The article presents a calendar of events related to computers. The 1985 National Computer Conference will be held on July 15 to 18 in Chicago, Illinois. The Artificial Intelligence in Economics and Management workshop will be held on March 12 to 14, 1985, in Zurich, Switzerland. The World Conference on Computers in Education (WCCE) will be held on July 29 to August 2, 1985, in Norwolk, Virginia.

The article offers information on various conferences for professionals. The Working Conference on Prototyping will be held on October 25-28, 1983 at Hotel Sofitel in Namur, Belgium. The International Workshop on Models and Languages for Software Specification and Design will be held on March 30, 1984 in Orlando, Florida. The 1984 National Education Computing Conference will be held on June 13-15 in Dayton, Ohio.

The article presents a calendar of professional activities and special events concerning the Association of Computing Machinery. Activities feature meetings and symposiums in programming languages, computer architecture, softair program, information technology, and other important meetings about computers.

In this paper an axiomatic, fundamental metamodel of data flow is constructed. The components of the metamodel are the states along the flow of data: physical events, language (data), stored data, human data processing, and decision making. Transfers front one state to another are performed by functions: coding, keying, processing, perception, and human acting. The entire flow is evaluated by a value function. Each of the states and functions is rigorously described by means of definitions, axioms, and theorems. The main purpose of the meta model is to provide a common framework for various models in MIS and consequently to remedy the "Tower of Babel" syndrome prevailing in this area. The way the metamodel can he used to develop other models in MIS is explained in the last part of the paper. [ABSTRACT FROM AUTHOR]

The article offers news briefs related to information technology. The Association for Systems Management (ASM) has announced a program to certify systems personnel and to recertify every three years those who continue their educations and comply with a code of conduct. The organization Information Age Institute has been formed to study the impact of information technology in Washington, D.C.

This paper discusses a family of algorithms for computing the volume, moments of inertia, and other integral properties of geometrically complex solids, e.g. typical mechanical parts. The algorithms produce approximate decompositions of solids into cuboid cells whose integral properties are easy to compute. The paper focuses on versions of the algorithms which operate on solids represented by Constructive Solid Geometry (CSG), i.e., as set-theoretical combinations of primitive solid "building blocks." Two known algorithms are summarized and a new algorithm is presented. The efficiencies and accuracies of the three algorithms are analyzed theoretically and compared experimentally. The new algorithm uses recursive subdivision to convert CSG representations of complex solids into approximate cellular decompositions based on variably sized blocks. Experimental data show that the new algorithm is efficient and has predictable accuracy. It also has other potential applications, e.g., in producing approximate octree representations of complex solids and in robot navigation. [ABSTRACT FROM AUTHOR]

This paper presents a model of an I/O subsystem in which devices can be accessed from multiple CPUs and/or via alternative channel and control unit paths. The model estimates access response times, given access rates for all CPU-device combinations. Central to the model's algorithm is the estimation of the rotational position sensing (RPS) miss probabilities by means of the maximum entropy principle. [ABSTRACT FROM AUTHOR]

The article presents news briefs concerning the Association of Computing Machinery (ACM). Mostek Corp. has become Corporate Member of ACM. ACM modified its own copyright procedures with respect to papers published in ACM journals. John Tartar has been appointed ACM Chairman of the External Activities Board.

Analytical results, related to the availability of a computer system constructed of unreliable processors, are presented in this paper. These results are obtained by using various computer-aided algebraic manipulation techniques. A major purpose of this paper is to demonstrate that the difficulties of obtaining analytical solutions to Markov processes can be considerably reduced by the application of symbol manipulation programs. Since many physical systems can be modeled by Markov and semi-Markov processes, the potential range of application of these techniques is much wider than the problem of availability analyzed here. [ABSTRACT FROM AUTHOR]

Foreword. At every standards meeting, in clear view on the table there should be a small plaque engraved: "Do it once, do it right, do it internationally." The many contributions of Douglas Ross exemplify this directive. If, for example, you look at the ASCII standard, ANSI-X3.4-1968, you will find that D.T. Ross represented ACM on the ANSI X3 Committee at that time. This paper is part of an argument that well-founded standards go hand in hand with an effective systems methodology. When first submitted for refereeing, "Homilies for Humble Standards" was oriented toward Computer Aided Manufacturing (CAM) applications. As it is now published, the context is elevated to consider all applications. In a similar manner, we can broaden the scope to show that it is the concern of all ACM members. Manufacturing is the application of tools and processes on materials to create a product. Languages are our tools, algorithms and procedures are our processes, data is our material. The product is an enhancement of the power and span of control of the customer. I commend this paper for your reading as one of the relatively few in ACM publications which tell why ACM and its members should be "involved", it discusses an unsolved problem, rather than a solution looking for a problem. [ABSTRACT FROM AUTHOR]

Clenshaw-Curtis quadrature is a particularly important automatic quadrature scheme for a variety of reasons, especially the high accuracy obtained from relatively few integrand values. However, it has received little use because it requires the computation of a cosine transformation, and the arithmetic cost of this has been prohibitive. This paper is in two parts; a companion paper, "II Computing the Cosine Transformation," shows that this objection can be overcome by computing the cosine transformation by a modification of the fast Fourier transform algorithm. This first part discusses the strategy and various error estimates, and summarizes experience with a particular implementation of the scheme. [ABSTRACT FROM AUTHOR]

In a companion paper to this, "I Methodology and Experiences," the automatic Clenshaw-Curtis quadrature scheme was described and how each quadrature formula used in the scheme requires a cosine transformation of the integrand values was shown. The high cost of these cosine transformations has been a serious drawback in using Clenshaw-Curtis quadrature. Two other problems related to the cosine transformation have also been troublesome. First, ... conventional computation of the cosine transformation by recurrence relation is numerically unstable, particularly at the low frequencies which have the largest effect upon the integral. Second, in case the automatic scheme should require refinement of the sampling, storage is required to save the integrand values after the cosine transformation is computed. This second part of the paper shows how the cosine transformation can be computed by a modification of the fast Fourier transform and all three problems overcome. The modification is also applicable in other circumstances requiring cosine or sine transformations, such as polynomial interpolation through the Chebyshev points. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to present a comparison of some computer simulation languages and of some of the packages by which each is implemented. Some considerations involved in comparing software packages for digital computers are discussed In Part I. The issue is obvious: users of digital computers must choose from available languages or write their own. Substantial costs can occur, particularly in training, implementation and computer time if an inappropriate language is chosen. More and more computer simulation languages are being developed: comparisons and evaluations of existing languages are useful for designers and implementers as well as users. The second part is devoted to computer simulation and simulation languages. The computational characteristics of simulation are discussed with special attention being paid to a distinction between continuous and discrete change models. Part III presents a detailed comparison of six simulation languages and packages: SIMSCRIPT, CLP, CSL, GASP, GPSS and SOL. The characteristics of each are summarized in a series of tables. The implications of this analysis for designers of languages, for users, and for implementers are developed. The conclusion of the paper is that the packages now available for computer simulation offer features which none of the more general-purpose packages do and that analysis of strengths and weaknesses of each suggests ways in which both current and future simulation languages and packages can be improved. [ABSTRACT FROM AUTHOR]

The article provides information on the origins of computer science and technology, in light of the 100th anniversary of the birth of computer scientist Alan Turing in 2012. The author emphasizes that Turing did not invent the computer. In 1936, Turing launched the concept called the Turing Machine, which has become the main abstract model of computation used by computer scientists. After the Second World War, he designed an electronic computer called the automatic computing engine (ACE) for the National Physical Laboratory in London, England. It discusses the role of Turing in the founding of theoretical computer science.