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This paper describes a data base management system under development at Kansas State University, intended for use in a network composed primarily of minicomputers. The report presents a description of the computers forming the network and their intercomputer communication system. The data base management system is a network type as specified by CODASYL. An extension of a CODASYL-type DBMS to multicomputer configurations is presented and several DBMS network topologies are discussed. We then conclude with a discussion of a completely distributed data base network. (Author)

This paper describes a data base management system under development at Kansas State University, intended for use in a network composed primarily of minicomputers. The report presents a description of the computers forming the network and their intercomputer communication system. The data base management system is a network type as specified by CODASYL. An extension of a CODASYL-type DBMS to multicomputer configurations is presented and several DBMS network topologies are discussed. We then conclude with a discussion of a completely distributed data base network. (Author)

The Aircraft Noise Predication Program (ANOPP) is an industry-wide tool used to predict turbofan engine flyover noise in system noise optimization studies. Its goal is to provide the best currently available methods for source noise prediction. As part of a program to improve the Heidmann fan noise model, models for fan inlet and fan exhaust noise suppression estimation that are based on simple engine and acoustic geometry inputs have been developed. The models can be used to predict sound power level suppression and sound pressure level suppression at a position specified relative to the engine inlet.

This is the final report of Contract N00014-76-C-0866, covering a broad descriptive and critical survey of the literature on human factors in computer systems. The basic purpose of this effort was to assess the current state of the art in this area in order to evaluate the feasibility of developing a human factors guide to computer system design. Two technical reports were issued under this contract. The first is a critically annotated and heavily indexed bibliography of 564 reports selected from the surveyed literature. The second is a critical overview of the state of the art, with recommendations for a design guide. The basic conclusion of this study is that a human factors design guide for interactive systems -- which discusses issues, alternatives, and methods in the context of the design process -- is both feasible and needed. The current state of the art was not found adequate to support the development of a quantitative reference handbook in this area. (Author)

xvii, 420 pages

Conducting a survey of manpower training needs of business and industry in Connecticut and identifying elements of a vocational-career information delivery system were the two major focuses of the study described in this report. Content is presented in three chapters. Chapter 1 reviews and analyzes the manpower training needs survey and results. Some of the major findings/conclusions presented are (1) Connecticut's businesses are unable to tell Connecticut's educational agencies what they need in numerical terms from the various training programs administered by the State. Long range needs of private firms are too poorly perceived to be a basis of planning by educational agencies. (2) Although Connecticut's enterprises are critical about the quality of the vocational graduates reaching them, they are unaggressive and probably unled as to the direction to take in addressing the issue. (3) There is no common occupational language employed across the State. Chapter 2 discusses long range manpower forecasting techniques and other approaches and methods for predicting manpower needs. Chapter 3 brings together a number of considerations into a model which incorporates essential elements of a complete career guidance program. The appendixes contain raw data about occupational demand and supply. (SH)

One of the major obstacles to the widespread development and utilization of distributed data base management systems is the lack of an efficient recovery technique. A methodology is presented here for recovery of distributed data bases. The central operation of the recovery technique is rollback of a data base application task on the processor which controls access to the data. The rollback procedure restores the data base to its original state prior to the execution of the application task and determines the set of applications tasks which may have been effected by that task. Tasks that have not operated upon data altered by tasks being rolled back are not affected by the procedure. The rollback procedure attempts to minimize the time and space requirements for recovery. (Author)

52 pages

The purpose of this thesis is to develop a high-level model to create self-adapting software which teaches learning-disabled (LD) children to read. This approach identifies and discusses the fundamental concepts of learning, motivation, learning disabilities, the Theory of Multiple Intelligences, computer games, and intelligent computer-aided learning (ICAL). These concepts are then integrated into the design of a model that manipulates these concepts to teach reading skills. The result of this effort is CAPER (Computer-Assisted Personal Education Resource). It is model of a system that will: (a) identify the individual's dominant learning styles, (b) tailor the instruction and presentation to those styles, and (C) present the lessons in an interactive game-like style will retain the child's interest and enhance the learning process

In this paper we present an overview of data base management systems (DBMS), the motivation for distributed data base systems (DDBMS), a set of possible network topologies served by the distribution, the mechanisms necessary to integrate (and communicate between) the DDBMS system elements when distributed across a nonhomogeneous network of minicomputers, and some implementation details on a prototype system. The current prototype distributes the DBMS and application program function across an IBM 370/158 and a (minicomputer) NOVA 2/10. In the near future, a third machine, the Interdata 85 minicomputer, will be added to the network. The DBMS used is a network system as specified by CODASYL. The emphasis in this paper will be on the problems posed by the heterogeneous machines and the intertask (processor) communication system which is utilized in the distribution of data, programs, and control. (Author)

The problem of deadlock in distributed data base management is analyzed in terms of performance effects of potential deadlock handling schemes. The performance tradeoffs of deadlock detection and deadlock prevention for distributed data base management systems are compared. Since the run-time overhead in deadlock prevention is projected to be less than for deadlock detection, an algorithm for preventing deadlocks in distributed data base systems is developed. The critical information for the deadlock prevention algorithm is maintained in a shared record list. The shared record list contains all shared access records for a set of tasks. Shared records lists are maintained dynamically by the run-time system. A proof that the algorithm prevents deadlocks in a distributed data base management system is provided along with a comprehensive example. (Author)

The results of a simulation study intended to determine the circumstances under which it is beneficial to operate a data base management system with a multi-processor backend are presented. The basic concept of backend data base management systems and multi-processor backend systems are provided as background material. The general structure of the simulation model which has been implemented in GPSS is outlined. The results of the study indicate that the amount of CPU activity required by the data base management system is a determining factor with respect to the need for a multi-processor backend. (Author)

A memory management scheme which incorporates an additional level of memory into the traditional primary-secondary storage hierarchy is proposed for utilization in distributed data base management systems. In this scheme, the memory of the back-end processor is used as an additional memory buffer. An optimal three-level memory management algorithm is presented along with an analysis of its cost in terms of page replacement. The expected performance improvement over the optimal algorithm for a two-level memory system is determined. The performance benefits of the three-level memory management are applicable to most distributed processing systems. (Author)

A system is safety-critical if its failure can endanger human life or cause significant damage to property or the environment. State-of-the-art computer systems on commercial aircraft are highly complex, software-intensive, functionally integrated, and network-centric systems of systems. Ensuring that such systems are safe and comply with existing safety regulations is costly and time-consuming as the level of rigor in the development process, especially the validation and verification activities, is determined by considerations of system complexity and safety criticality. A significant degree of care and deep insight into the operational principles of these systems is required to ensure adequate coverage of all design implications relevant to system safety. Model-based development methodologies, methods, tools, and techniques facilitate collaboration and enable the use of common design artifacts among groups dealing with different aspects of the development of a system. This paper examines the application of model-based development to complex and safety-critical aircraft computer systems. Benefits and detriments are identified and an overall assessment of the approach is given.

A method of representation of a solution as segments of the series in powers of the step of the independent variable is expanded for solving complex systems of ordinary differential equations (ODE): the Lorenz system and other systems. A new procedure of reduction of the representation of the solution to a sum of two parts (regular and random) is performed. A shifting procedure is applied in each level of the independent variable to the random part and it acts as the filter that extracts the values to the regular part. In certain cases it is possible to omit the random part and construct the approximation which does not converge but still provides the qualitative information about the full solution (a linear approximation provides a simple exact solution). Evaluation of the error for this case is performed. Constructing the analytical representation of the solutions for these systems by the developed method is presented.

This paper summarizes major experiences and practices of information development units of state-based career information systems which produce accurate, current, and localized occupational and educational information for career planning. It is intended as a guide for states considering setting up a similar system and for staff members in presently developing state-based systems of career information. Sections of the paper provide explanations and detail related to these areas: (1) characteristics of good information, (2) definition of an implementation strategy to follow and information topics to be covered, (3) staffing the information development unit, (4) use of a data collection strategy that relies on existing data sources, (5) implementation of a systematic information updating design, and (6) use of workplans to organize major tasks. Appendixes include a workplan and job descriptions of information development unit staff. (YLB)

This paper proposes a product development methodology (PDM) for complex systems evolving within the current economic climate of the United States, as well as the unstable state of world affairs envisioned throughout the decade. The PDM facilitates the development of systems that are multipurpose, flexible, highly mobile, and incorporate maximum bang for the buck. Ironically, the unstable nature of the development environment within the defense community parallels the one encountered by the commercial sector over the last 20 years. Successful companies have responded by adopting a product development methodology that adapts to ever changing market demands and the concern for near term returns (profit). The PDM exploits lessons learned from the commercial market analogy to establish a flexible, low risk, cost effective approach for technological progress. The approach suits systems development, especially those involving complex mission critical computer systems. Examination of the commercial product development process reveals a strategy that can achieve the procurement flexibility needed by DoD. This strategy concentrates on leveraging the state-of-the-art in a cost effective manner. The strategy also addresses risk management.

The ability to converse effectively with technicians has been recognized as a critical skill for managers of data processing activities. This need has been addressed by the Association for Computing Machinery in their recommended curricula for the education of Information Systems specialists. Members of the Association have also described the functions of a graduate of those curricula to be that of a boundary spanner and a change agent. Other authors have identified that these skills need to be gained in practical environments, and that the manager needs to know at least a minimum of the technical language in order to select good technicians for his staff, and to communicate with that staff effectively. At the Naval Post-graduate School a course of instruction in technical aspects of the computer was designed into a newly constructed microcomputer laboratory. This thesis is the report of the evolution of that laboratory and course of instruction. (Author)

The results of a simulation study intended to determine the circumstances under which it is beneficial to operate a data base management system with a multi-processor backend are presented. The basic concept of backend data base management systems and multi-processor backend systems are provided as background material. The general structure of the simulation model which has been implemented in GPSS is outlined. The results of the study indicate that the amount of CPU activity required by the data base management system is a determining factor with respect to the need for a multi-processor backend. (Author)

This paper describes a data base management system under development at Kansas State University, intended for use in a network composed primarily of minicomputers. The report presents a description of the computers forming the network and their intercomputer communication system. The data base management system is a network type as specified by CODASYL. An extension of a CODASYL-type DBMS to multicomputer configurations is presented and several DBMS network topologies are discussed. We then conclude with a discussion of a completely distributed data base network. (Author)

This paper describes a data base management system under development at Kansas State University, intended for use in a network composed primarily of minicomputers. The report presents a description of the computers forming the network and their intercomputer communication system. The data base management system is a network type as specified by CODASYL. An extension of a CODASYL-type DBMS to multicomputer configurations is presented and several DBMS network topologies are discussed. We then conclude with a discussion of a completely distributed data base network. (Author)

In this paper we present an overview of data base management systems (DBMS), the motivation for distributed data base systems (DDBMS), a set of possible network topologies served by the distribution, the mechanisms necessary to integrate (and communicate between) the DDBMS system elements when distributed across a nonhomogeneous network of minicomputers, and some implementation details on a prototype system. The current prototype distributes the DBMS and application program function across an IBM 370/158 and a (minicomputer) NOVA 2/10. In the near future, a third machine, the Interdata 85 minicomputer, will be added to the network. The DBMS used is a network system as specified by CODASYL. The emphasis in this paper will be on the problems posed by the heterogeneous machines and the intertask (processor) communication system which is utilized in the distribution of data, programs, and control. (Author)

One of the major obstacles to the widespread development and utilization of distributed data base management systems is the lack of an efficient recovery technique. A methodology is presented here for recovery of distributed data bases. The central operation of the recovery technique is rollback of a data base application task on the processor which controls access to the data. The rollback procedure restores the data base to its original state prior to the execution of the application task and determines the set of applications tasks which may have been effected by that task. Tasks that have not operated upon data altered by tasks being rolled back are not affected by the procedure. The rollback procedure attempts to minimize the time and space requirements for recovery. (Author)

3 MAR 1969 SUBJECT OER/OSR Cooperation in Computer Analysis Systems Development 1. I appreciate receiving copies of your correspondence with the DDI concerning the estab- lishment of an OER Systems Development Staff. I will see that the branches and divisions in OSR are informed of this development and cooperate fully in analytical areas where OSR and OER share common interests. 2. Your note reminds me that it is now nearly a year since we last discussed the subject of research and modelling in the area of Soviet input-output analysis. During this time work has progressed on the OSR Military-Economic Planning Model (MILPLAN). We are now satisfied with its theoretical construct and the computer program can now be run on the Agency's systems. 3. We are proceeding on research to bring MILPLAN to a fully operational status for analyti- cal application. This involves bringing up to date our production function inputs and formulat- ing alternative plan scenarios. The data handling and research required make a systematic approach imperative. 4. To implement such an approach we have pre- pared a sample Soviet Input-Output Data Handbook, de- signed a) to catalog all completed, planned and contemplated research, b) to show complete methodo- logy and sourcing for all estimates including any computer programs used in deriving these estimates and c) to reference all pertinent ADP files. An example of what we have in mind is attached. Approved For Release 1999109108: CIA-RDP79B00972A000100600002-3 EAf~ !` ' - `C11iIN0. u r;d a Cr' !i .q. `q I Approved For Releaser1999/09/08: CIA-RDP79B00972A00010 M0002-3 5. Most of the data inputs that are re- quired for MILPLAN are general to input-output analysis and are relevant to the interests of both Offices. This would recommend a close co- ordination of OER and OSR research efforts to assure efficient use of analytical and computer resources. I think a formal exchange between OER and OSR is now in order. Because of the need for a common data base -- some of which is devel- oped from OER research and some from OSR -- I suggest consideration of an inter-office system such as the attached Soviet Input-Output Data Handbook. 6. After your staff has had an opportunity to study this approach, I suggest we get together + nv ra?O?e views. In the meantime, ploring with your stall e details of developing an inter-office data base and documentation sys- tem, with a view toward sharing the research burden of cffnrt_ Director Strategic Research Distribution: Original & 1 - Addressee (w/attach.) 2 - OD/OSR 2 - SR/PA 1 - PA/C 1 - SR/PL 25X1A9a OSR/PA: ecb/x6233 (22 Feb. 69) - 2 - Approved For Release 1999109108: CIA-RDP79B00972A000100600002-3 ,~ ?_ , ??, MISSING PAGE

3 MAR 1969 SUBJECT OER/OSR Cooperation in Computer Analysis Systems Development 1. I appreciate receiving copies of your correspondence with the DDI concerning the estab- lishment of an OER Systems Development Staff. I will see that the branches and divisions in OSR are informed of this development and cooperate fully in analytical areas where OSR and OER share common interests. 2. Your note reminds me that it is now nearly a year since we last discussed the subject of research and modelling in the area of Soviet input-output analysis. During this time work has progressed on the OSR Military-Economic Planning Model (MILPLAN). We are now satisfied with its theoretical construct and the computer program can now be run on the Agency's systems. 3. We are proceeding on research to bring MILPLAN to a fully operational status for analyti- cal application. This involves bringing up to date our production function inputs and formulat- ing alternative plan scenarios. The data handling and research required make a systematic approach imperative. 4. To implement such an approach we have pre- pared a sample Soviet Input-Output Data Handbook, de- signed a) to catalog all completed, planned and contemplated research, b) to show complete methodo- logy and sourcing for all estimates including any computer programs used in deriving these estimates and c) to reference all pertinent ADP files. An example of what we have in mind is attached. Approved For Release 1999109108: CIA-RDP79B00972A000100600002-3 EAf~ !` ' - `C11iIN0. u r;d a Cr' !i .q. `q I Approved For Releaser1999/09/08: CIA-RDP79B00972A00010 M0002-3 5. Most of the data inputs that are re- quired for MILPLAN are general to input-output analysis and are relevant to the interests of both Offices. This would recommend a close co- ordination of OER and OSR research efforts to assure efficient use of analytical and computer resources. I think a formal exchange between OER and OSR is now in order. Because of the need for a common data base -- some of which is devel- oped from OER research and some from OSR -- I suggest consideration of an inter-office system such as the attached Soviet Input-Output Data Handbook. 6. After your staff has had an opportunity to study this approach, I suggest we get together + nv ra?O?e views. In the meantime, ploring with your stall e details of developing an inter-office data base and documentation sys- tem, with a view toward sharing the research burden of cffnrt_ Director Strategic Research Distribution: Original & 1 - Addressee (w/attach.) 2 - OD/OSR 2 - SR/PA 1 - PA/C 1 - SR/PL 25X1A9a OSR/PA: ecb/x6233 (22 Feb. 69) - 2 - Approved For Release 1999109108: CIA-RDP79B00972A000100600002-3 ,~ ?_ , ??, MISSING PAGE

This paper describes the use of computer graphic simulation techniques to resolve critical design and operational issues for robotic systems. Use of this technology will result in greatly improved systems and reduced development costs. The major design issues in developing effective robotic systems are discussed and the use of ROBOSIM, a NASA developed simulation tool, to address these issues is presented. Three representative simulation case studies are reviewed: off-line programming of the robotic welding development cell for the Space Shuttle Main Engine (SSME); the integration of a sensor to control the robot used for removing the Thermal Protection System (TPS) from the Solid Rocket Booster (SRB); and the development of a teleoperator/robot mechanism for the Orbital Maneuvering Vehicle (OMV).

This volume reproduces a sample of Southwest Regional Laboratory for Educational Research and Development (SWRL) Technical Notes and Technical Memoranda produced in 1972 dealing with natural language analysis and student-instruction interaction facets of the organization's computer-based research effort. Part I contains three papers describing aspects of the SWRL Language Analysis Package. Part II contains four papers dealing with the Instructional Development Control and Monitoring System. Part III presents abstracts of SWRL Technical Notes and Technical Memoranda produced in 1971 and 1972 bearing on natural language analysis, student-instruction interaction, and related matters. (HAB)

Thesis advisor(s): Yuh-jeng Lee ; John A. Daley

This paper describes a data base management system under development at Kansas State University, intended for use in a network composed primarily of minicomputers. The report presents a description of the computers forming the network and their intercomputer communication system. The data base management system is a network type as specified by CODASYL. An extension of a CODASYL-type DBMS to multicomputer configurations is presented and several DBMS network topologies are discussed. We then conclude with a discussion of a completely distributed data base network. (Author)

The combination of general purpose data base management systems and computer networks to produce distributed data base management systems should be the next significant step in commercial systems development. A completely generalized distributed data base management system would reside on a heterogeneous computer network with different data base systems available at various processors. Communication and data transfer would be possible between any nodes in the network. This report described the principal problem areas in distributed data base management system development. Distributed data base systems share many design problems with both single machine data base systems and computing networks, as well as introducing several new dilemmas. Recent research in these problem areas is presented to provide a picture of the state of the art of distributed data base development. In addition, the current status of the data base industry with respect to distributed processing is evaluated by reporting the current projects and future plans of selected (anonymous) data base vendors.

The combination of general purpose data base management systems and computer networks to produce distributed data base management systems should be the next significant step in commercial systems development. A completely generalized distributed data base management system would reside on a heterogeneous computer network with different data base systems available at various processors. Communication and data transfer would be possible between any nodes in the network. This report described the principal problem areas in distributed data base management system development. Distributed data base systems share many design problems with both single machine data base systems and computing networks, as well as introducing several new dilemmas. Recent research in these problem areas is presented to provide a picture of the state of the art of distributed data base development. In addition, the current status of the data base industry with respect to distributed processing is evaluated by reporting the current projects and future plans of selected (anonymous) data base vendors.

A software organization is presented to provide for data definition and manipulation in a distributed data base management system. With the mechanism for distributing the data base proposed here, the physical location of the data is transparent to the user program. A Device Media Control Language is specified for the assignment of control of and access to a data base area to a set of processors. Procedures for reassignment of the control and access functions as well as the transfer of data between processors are provided. The basic hardware and software requirements for a computer network capable of supporting a distributed data base management system are discussed along with a specification of the software required for a processor in a distributed data base network. (Author)

The elements of a simulation program written in Ada were developed. The program will eventually serve as a data generator of typical readings from various space station equipment involved with Communications and Tracking, and will simulate various scenarios that may arise due to equipment malfunction or failure, power failure, etc. In addition, an evaluation of the Ada language was made from the viewpoint of a FORTRAN programmer learning Ada for the first time. Various strengths and difficulties associated with the learning and use of Ada are considered.

Development of an expert system is difficult because of two challenges involve in it. The first one is the expert system itself is high level system and deals with knowledge, which make is difficult to handle. Second, the systems development is more art and less science; hence there are little guidelines available about the development. This paper describes computer aided development of intelligent systems using modem artificial intelligence technology. The paper illustrates a design of a reusable generic framework to support friendly development of fuzzy, neural network and hybrid systems such as neuro-fuzzy system. The reusable component libraries for fuzzy logic based systems, neural network based system and hybrid system such as neuro-fuzzy system are developed and accommodated in this framework. The paper demonstrates code snippets, interface screens and class libraries overview with necessary technical details.

Department of Defense information processing and command and control require research, experimentation, evaluation, synthesis, documentation, demonstration, production and transfer. The Demonstration and Development Facility (DDF) was the first stage in the fulfillment of this requirement and a low-bandwidth video teleconferencing network is the most recent development designed to meet these myriad requirements. Both the first and most recent stages were designed to meet the needs of the commander for understanding information and communicating decisions.

A software organization is presented to provide for data definition and manipulation in a distributed data base management system. With the mechanism for distributing the data base proposed here, the physical location of the data is transparent to the user program. A Device Media Control Language is specified for the assignment of control of and access to a data base area to a set of processors. Procedures for reassignment of the control and access functions as well as the transfer of data between processors are provided. The basic hardware and software requirements for a computer network capable of supporting a distributed data base management system are discussed along with a specification of the software required for a processor in a distributed data base network. (Author)

The combination of general purpose data base management systems and computer networks to produce distributed data base management systems should be the next significant step in commercial systems development. A completely generalized distributed data base management system would reside on a heterogeneous computer network with different data base systems available at various processors. Communication and data transfer would be possible between any nodes in the network. This report described the principal problem areas in distributed data base management system development. Distributed data base systems share many design problems with both single machine data base systems and computing networks, as well as introducing several new dilemmas. Recent research in these problem areas is presented to provide a picture of the state of the art of distributed data base development. In addition, the current status of the data base industry with respect to distributed processing is evaluated by reporting the current projects and future plans of selected (anonymous) data base vendors.

This paper presents a methodology for and an evaluation of the feasibility of converting a typical data processing system to a data base management system. This methodology is applied to a particular system. The data base management system under evaluation uses a back-end minicomputer to perform the data management functions. The evaluation is made in terms of changes in system resources, program requirements, and human factors. The results of this study provide considerable insight into the problem of conversion to a data base management system and suggest guidelines for the evaluation of any proposed data base conversions. (Author)

An interactive graphical interface helps intelligent computer- assisted instruction systems, because many applications can be well represented by graphic objects. One approach is a facility whereby a teacher constructing a tutor can associate specific graphics with specific predicate-calculus expressions describing a state in a tutoring simulation. This further requires a specification of the arrangement of graphic objects on the screen, how graphic objects can change position with simulation states. It also requires a language for teachers to specify graphic objects. This thesis addresses both. We introduce a broader applications of cartoon animation modelling ideas to tutoring, that have been limited so far by the complexity of their implementation. The special tools provided help computer-inexperienced instructors to develop their own cartoon animation modelling tutor without the need of mathematical description of shapes or activities to be represented. The tutor generator used employes means-ends analysis, and the language for the teachers is built using Prowindows, a Prolog extension for object-oriented design.

With the advent of Data Base Management Systems (DBMS) and associated facilities (data dictionaries, query languages, report writers, etc.), the task of data organization, management, and storage has been given to a select group of specialists. These specialists (the Data Base Administrators (DBA) provide the necessary control, logging, and access information and software to the program. Such activity relieves the programmers of this overhead function allowing them to concentrate on the necessary manipulations. This paper focuses on some alternatives with respect to a DBMS in terms of a centralized versus decentralized environment. The first section deals with the concepts and tradeoffs involved in considering the two environments. The second section then deals with problems which are encountered in a distributed data base management system. These problems include deadlock, rollback and recovery, data conversion, redundancy, and communication and operating system requirements for effective distribution.

This paper presents a methodology for and an evaluation of the feasibility of converting a typical data processing system to a data base management system. This methodology is applied to a particular system. The data base management system under evaluation uses a back-end minicomputer to perform the data management functions. The evaluation is made in terms of changes in system resources, program requirements, and human factors. The results of this study provide considerable insight into the problem of conversion to a data base management system and suggest guidelines for the evaluation of any proposed data base conversions. (Author)

The problem of deadlock in distributed data base management is analyzed in terms of performance effects of potential deadlock handling schemes. The performance tradeoffs of deadlock detection and deadlock prevention for distributed data base management systems are compared. Since the run-time overhead in deadlock prevention is projected to be less than for deadlock detection, an algorithm for preventing deadlocks in distributed data base systems is developed. The critical information for the deadlock prevention algorithm is maintained in a shared record list. The shared record list contains all shared access records for a set of tasks. Shared records lists are maintained dynamically by the run-time system. A proof that the algorithm prevents deadlocks in a distributed data base management system is provided along with a comprehensive example. (Author)

In this paper we present an overview of data base management systems (DBMS), the motivation for distributed data base systems (DDBMS), a set of possible network topologies served by the distribution, the mechanisms necessary to integrate (and communicate between) the DDBMS system elements when distributed across a nonhomogeneous network of minicomputers, and some implementation details on a prototype system. The current prototype distributes the DBMS and application program function across an IBM 370/158 and a (minicomputer) NOVA 2/10. In the near future, a third machine, the Interdata 85 minicomputer, will be added to the network. The DBMS used is a network system as specified by CODASYL. The emphasis in this paper will be on the problems posed by the heterogeneous machines and the intertask (processor) communication system which is utilized in the distribution of data, programs, and control. (Author)

One of the major obstacles to the widespread development and utilization of distributed data base management systems is the lack of an efficient recovery technique. A methodology is presented here for recovery of distributed data bases. The central operation of the recovery technique is rollback of a data base application task on the processor which controls access to the data. The rollback procedure restores the data base to its original state prior to the execution of the application task and determines the set of applications tasks which may have been effected by that task. Tasks that have not operated upon data altered by tasks being rolled back are not affected by the procedure. The rollback procedure attempts to minimize the time and space requirements for recovery. (Author)

One of the major obstacles to the widespread development and utilization of distributed data base management systems is the lack of an efficient recovery technique. A methodology is presented here for recovery of distributed data bases. The central operation of the recovery technique is rollback of a data base application task on the processor which controls access to the data. The rollback procedure restores the data base to its original state prior to the execution of the application task and determines the set of applications tasks which may have been effected by that task. Tasks that have not operated upon data altered by tasks being rolled back are not affected by the procedure. The rollback procedure attempts to minimize the time and space requirements for recovery. (Author)

One of the major obstacles to the widespread development and utilization of distributed data base management systems is the lack of an efficient recovery technique. A methodology is presented here for recovery of distributed data bases. The central operation of the recovery technique is rollback of a data base application task on the processor which controls access to the data. The rollback procedure restores the data base to its original state prior to the execution of the application task and determines the set of applications tasks which may have been effected by that task. Tasks that have not operated upon data altered by tasks being rolled back are not affected by the procedure. The rollback procedure attempts to minimize the time and space requirements for recovery. (Author)

The combination of general purpose data base management systems and computer networks to produce distributed data base management systems should be the next significant step in commercial systems development. A completely generalized distributed data base management system would reside on a heterogeneous computer network with different data base systems available at various processors. Communication and data transfer would be possible between any nodes in the network. This report described the principal problem areas in distributed data base management system development. Distributed data base systems share many design problems with both single machine data base systems and computing networks, as well as introducing several new dilemmas. Recent research in these problem areas is presented to provide a picture of the state of the art of distributed data base development. In addition, the current status of the data base industry with respect to distributed processing is evaluated by reporting the current projects and future plans of selected (anonymous) data base vendors.

The volume contains six supportin studies. Described are a number of models for determining the cost and effectiveness of decontaminating municipal areas. One study examines the system components of a command and control system for municipal decontamination. These studies cover the following subjects: (1) A Feasibility Study of the Application of Analog Computers to the Analysis of Decontamination; (2) A circular Model for Approximating Gamma Ray Intensity at a Single Detector Location; (3) A Square-Grid Model for Approximating Gamma Ray Intensity at a Single Detector Location; (4) A Point Source Model for Approximating Gamma Ray Intensity at a Single Detector Location (The Equivalent Planes Method); (5) A FORTRAN Program for Decontamination Analysis; and (6) The Nature and Scope of Command and Control System Elements Required for Conducting Effective Decontamination in Municipalities.

The problem of deadlock in distributed data base management is analyzed in terms of performance effects of potential deadlock handling schemes. The performance tradeoffs of deadlock detection and deadlock prevention for distributed data base management systems are compared. Since the run-time overhead in deadlock prevention is projected to be less than for deadlock detection, an algorithm for preventing deadlocks in distributed data base systems is developed. The critical information for the deadlock prevention algorithm is maintained in a shared record list. The shared record list contains all shared access records for a set of tasks. Shared records lists are maintained dynamically by the run-time system. A proof that the algorithm prevents deadlocks in a distributed data base management system is provided along with a comprehensive example. (Author)

The problem of deadlock in distributed data base management is analyzed in terms of performance effects of potential deadlock handling schemes. The performance tradeoffs of deadlock detection and deadlock prevention for distributed data base management systems are compared. Since the run-time overhead in deadlock prevention is projected to be less than for deadlock detection, an algorithm for preventing deadlocks in distributed data base systems is developed. The critical information for the deadlock prevention algorithm is maintained in a shared record list. The shared record list contains all shared access records for a set of tasks. Shared records lists are maintained dynamically by the run-time system. A proof that the algorithm prevents deadlocks in a distributed data base management system is provided along with a comprehensive example. (Author)