Showing papers in "Ibm Systems Journal in 1979"

A distributed information system study

Abstract: This paper is a discussion of a methodology, a distributable information system model, and an experiment used to identify potential problems for supporting such a system. The experimental model was designed and implemented in an evolutionary manner for the purpose of studying the feasibility of a system with the postulated attributes. Incentives for distribution and design of the study introduce the two main topics--the study model itself and the implementation of the study model. Results of the study provide insights into such factors in distributed information system structural design as intercomponent communication, system control, and recovery philosophy.

A research perspective on computer-assisted office work

Abstract: The integrated office system of the future that relies upon computerized applications for most routine work will have to be a friendly system that can be used by individuals with a minimum of training and no previous computing experience A discussion of the computer-assisted aids to office work that have evolved at the IBM Thomas J Watson Research Center provides a preview of the possibilities for future office systems based on computers We describe tasks that have been computerized, the environment in which automated office applications are used, and the reactions of people who use the computer for routine office work

VM/370: a study of multiplicity and usefulness

Abstract: This paper is an overview of IBM'S Virtual Machine Facility/370. It describes the virtual machine concept and its capabilities and implementation in VM/370. Two components of VM/370 are discussed-the control program and the Conversational Monitor System. The usefulness of VM/370 in multiple and diverse environments is covered. New developments in VM/370 from hardware assists to system extensions, networking, and handshaking are briefly described as an introduction to the rest of the papers in this issue.

Routing and flow control in systems network architecture

Abstract: Systems Network Architecture (SNA) has been enhanced to include features that address the topological, routing, congestion, reliability, and availability problems of networks. An important aspect of this new release of SNA is that it allows multiple active routes between network nodes. Multiple routing permits sessions between network users to use alternate routes in case of unexpected or planned route disruptions. In this paper, the multiple routing architecture of SNA is described. An unrestricted data flow into the network can cause long delays and buffer depletion. Network congestion can be avoided by employing flow control mechanisms at both the local (node) and global (network) levels. This paper focuses on global flow control and describes the adaptive trafic-pacing "window" size algorithm that is the basis of the global flow control in SNA.

SNA multiple-system networking

Abstract: Systems Network Architecture (SNA) has evolved from an architecture that supported implementation of tree networks rooted in a System/370 to an architecture that supports multiple-system networks with capabilities such as alternate paths and parallel links. This paper describes the major SNA enhancements that have been implemented for multiple-system networks. As network configurations have become more complex, the problems associated with network growth, change, failures, recovery, and flow control have required solutions that permit continuous network operation. The SNA enhancements that address these problems are also discussed.

Managing VM/CMS systems for user effectiveness

Abstract: Discussed in this paper is a computing center management methodology based on the premise that the computer user's time and work product are valuable. Experience in the use of interactive systems in a research environment from 1965 to the present time is presented. Current user experience and management of VM/ CMS are emphasized. The use of computers as tools for extending users'powers of memory and logic and the development of new methods of managing VM/CMS are discussed in detail.

An office communications system

Abstract: In developing a prototype of an ofice communications system, an office study was first done to specify requirements for the prototype. The study focused on the productivity of three groups of employees: principals, clerical personnel, and secretaries. With requirements set by the management of the ofice used as a framework, application requirements for end users of an ofice communications system were established. From a subset of these requirements the prototype was developed. The prototype system was designed as an experimental learning system to provide managers and professionals with an easy, fast, and direct method for handling their business communications. The prototype was set up on IBM premises for testing and evaluation. Results of this operation are included in the discussion.

The changing virtual machine environment: interfaces to real hardware, virtual hardware, and other virtual machines

Abstract: This paper is a survey of changes to virtual machine interfaces, implementation, architecture, and simulation techniques as they affect IBM System/370 and 303X (3031, 3032, 3033) processors, the system control program to which virtual machines interface, and other virtual machines executing on the same real computing system or elsewhere. The paper seeks to summarize such changes and provide a perspective on the virtual machine environment. New uses of virtual machine subsystems are discussed as they relate to inter-virtual-machine communication.

Evolution of a virtual machine subsystem

Abstract: Early investigation of virtual machine subsystem flexibility centered on telecommunications support and intercomputer networking and proceeded in two phases. The first phase focused on an experimental program for the virtual machine control program CP-67 that supported remote work stations and pioneered intercomputer spool communications. The results of that effort inspired a second effort in the same area with some significant redirection. This second phase ultimately led to the remote spooling communications subsystem component of VM/370, the VM/370 networking package (VNET), and a large network of interactive computer systems within IBM. These phases are discussed along with suggestions for several continuing lines of work based on current results.

An introduction to network architectures and protocols

Abstract: This tutorial paper is intended for the reader who is unfamiliar with computer networks, to prepare him for reading the more detailed technical literature on the subject. The approach here is to start with an ordered list of the functions that any network must provide in tying two end users together, and then to indicate how this leads naturally to layered peer protocols out of which the architecture of a computer network is constructed. After a discussion of a few block diagrams of private (commercially provided) and public (common carrier) networks, the layer and header structures of SNA and DNA architectures and the X.25 interface are briefly described.

SNA and emerging international standards

Abstract: Public data networks are now being designed and implemented to handle the expansion of data communications. The interaction of Systems Network Architecture (SNA) and the international standards now being developed is discussed. A provisional architecture model is used as the basis for discussion, and SNA is compared to each level of the model.

VM/370 asymmetric multiprocessing

Abstract: The design and implementation of VM/370 attached processor support is discussed from the point of view of adding radical new function to an existing operating system. Three major design decisions are described, and performance is analyzed as it relates to those decisions.

Performance analysis of complex communications systems

Abstract: This paper discusses the designing of complex teleprocessing systems using a discrete simulation modeling tool, the Systems Network Analysis Program/Simulated Host Overview Technique (internally and informally called SNAP/SHOT). This modeling tool aids in designing computer communications systems composed of local and remote terminals, teleprocessing lines, host processors that control the teleprocessing lines, and interconnected communications systems. The model is capable of analyzing both tree- and mesh-structured networks.

An integrated approach to centralized communications network management

Abstract: Recent technological advances have increased the size and number of teleprocessing networks as well as broadened their scope and complexity. This added size and complexity has magnified the need for communications network management. One approach to communications network management is to provide centralized control which is integrated into the Systems Network Architecture user network. This approach is described in this paper by focusing on two program products that provide centralized operator control and problem determination capabilities for a network.

Public data networks: their evolution, interfaces, and status

Abstract: This paper has traced the development of PDNS from services based on the analog telephone network to services using digital techniques.

Distributed processing: an assessment

Abstract: Highlighted in this technical essay are discussions of the nature of distributed systems, design processes associated with the distribution of processing, and the conditions under which benefits accrue. The essay concentrates on some of the major benefits expected from distributed systems so as to provide a context in which to judge particular designs and their benefits. Among the judgment-informing considerations are the following: centralized management, historical relationships with on-line systems, reliability and fail-soft, security and privacy, system growth and capacity limitations, and fitting the system to the organizational structure.

Computing and communications: a perspective of the evolving environment

Abstract: Telecommunications regulation is an important public policy consideration and is presently the topic of much debate. The author presented a technical viewpoint of this topic, particularly with regard to possible applications and how the data processing industry could be involved, during the Keynote Panel Session at IEEE Compcon '78 held on September 6, 1978. His presentation is printed here.

State sampling of interactive VM/370 users

Abstract: Sampling the state of interactive computer users of harware and programming in a time-sharing system leads to an understanding of delays to users caused by contentionf or resources. This paper discusses user state sampling by means of a program called VM/ Monitor on the interactive time-sharing system, VM/370, although the methodology is applicable to other time-sharing systems. Also discussed are system bottleneck detection and secondary tuning after bottlenecks have been found. Possible extensions of the technique are also presented.

I/O facilities of the Distributed Processing Programming Executive (DPPX)

Abstract: This paper introduces the input/output facilities of DPPX, the Distributed Processing Programming Executive for the IBM 8100 Information Processing System. Design requirements and alternatives are discussed, as well as the general structure of the services that implement the I/O facilities. Services that support specific I/O resources, such as disk storage and communication devices, are related to the general structure. The paper considers some of the problems in designing a general structure to support a wide range of services, and it briefly describes the interface architecture used to solve these problems.

Virtual control storage: security measures in VM/370

Abstract: The architecture of a virtual machine system has specific advantages over that of conventional operating systems because virtual machines are well separated from one another and from the control program. This structure requires that a protected, multi-user resource manager be placed in a distinct virtual machine because the protection domain and scheduling unit are one entity, the virtual machine. But cooperation between distinct virtual machines necessarily entails scheduling overhead and often delay. This paper describes an experimental extension to VM/370 whereby a distinct execution and data domain (Virtual Control Storage) is made available to virtual machines that require access to a resource manager, without requiring a change in the scheduling unit. Thus scheduling overhead and delays are avoided when transition is made between user program and resource manager. A mechanism is described for exchanging data between execution domains by means of address-space mapping.

A formal approach for communication between logically isolated virtual machines

Abstract: The growing use of the virtual machine concept has resulted in the necessity for communication between the virtual machines. The design and operation of the Virtual Machine Communication Facility is discussed as an approach to offering such communication. The facility is an interface allowing a logical connection between two or more virtual machines. Potential applications for this facility conclude the discussion.

Potential technology implications for computers and telecommunications in the 1980s

Abstract: We have discussed s e technological trends and some technologies and have attempted to forecast some of the implications of each to communications and computing. Some general conclusions hich cut across technologies an worth reemphasia ing in omens global context: We are on the verge of an era in which we will have significantly re bandwidth and interconnection flexibility than we have ever had. It is likely than there will be more, inhially at least, than we now know how to use to advantage. Similarly, we will have a greatly enhanced capability to distribute processing among a large number of data processing hosts. At present, however, we have no good criteria by which to determine when distributed processing makes good long-term economic sense; frequently it is difficult even to see it distributed processing is currently feasible a given application situation because of the complexities introduced by sharing data bases and application logic, for example.

An operating system for distributed processing: DPPX

Abstract: The Distributed Processing Programming Executive (DPPX) is a new, full-function operating system designed to support distributed processing with the IBM 8100 Information System. The functional requirements of distributed processing and their solutions in DPPX are discussed. The structure of the operating system is outlined, and its advantages are analyzed. Highlighted are particular characteristics of the DPPX structure that uniquely support distributed processing.

Data management for the distributed processing programming executive (DPPX)

Abstract: The Data Management component of the new IBM 8100 Distributed Processing Programming Executive (DPPX) provides for the storage and retrieval of data on disk and tape. Its objectives are to support a broad range of functions and be easy to use, be easily extendible, and entail minimal cost for the user. The Data Management component is designed to meet those objectives by means of a layered structure, an improved concept of device independence, and the use of catalogs.

Evolution of a laboratory communication network

Abstract: This paper describes the IBM System Communications Division network and, using that network as an example, discusses some of the practical problems associated with providing computational and communication services to remote and local user communities.

Automatic programming for energy management using sensor based computers

Abstract: An automatic programming approach has been developed for the use of sensor based computers (IBM System/7 and Series/1) for energy management in buildings. The purpose is to aid the facilities engineer who is unfamiliar with programming and who requires a system that can be defined by a sequence of questions and answers. Programmers can add or modify application source programs to extend the system to other user-defined functions.

Design of the IBM 8100 data base and transaction management system: DTMS

Abstract: Transaction applications have specialized requirements for scheduling and data base support. This paper describes the procedure by which those requirements were identified during the design of a data base and transaction management program for the IBM 8100 Information System. It also provides an overview of the program structure that evolved to satisfy the functional requirements.