Mainframe Systems Research Articles

The changing nature of disk controllers

The evolution of the disk controllers that interface disk drive storage devices and subsystems with their hosts is reviewed. With magnetic disk storage density increasing by over five orders of magnitude in 37 years, the nature of the controller and its functions has undergone a significant change. In the 1960s, introduction of the IBM 360 and 370 systems led to architectures oriented to mainframe systems. In the 1980s, the personal computer brought into being the single-board controller most frequently attached to a single hard disk drive. In the 1990s, the functions that are being included within the drive are radically changing the attachment of a drive to a system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Plain SAILing with Swets

The serials control package from Swets, SAILS, has been around for many years but has so far made little impact on the library automation market. The system originated on mainframe systems but has recently been rewritten for the PC market and is about to be marketed commercially for the first time. The article describes the background to the development of the SAILS and its functionality.

Market mapping: how to use revolutionary new software to find, analyze, and keep customers

From the Publisher: Until now, the power to visualize, interpret, and display key market data on consumer behavior, population shifts, sales statistics, and more, and translate this information advantage into superior marketing, sales, and distribution decisions was reserved for firms with mega-market research dollars and complex mainframe systems. Market Mapping gives consumer and business-to-business marketers - in any industry - a cost-effective competitive edge. It shows how to combine the speed and power of desktop computers with revolutionary new mapping software to pinpoint customers, conduct market research, position products and services, and analyze consumer purchase patterns at a fraction of the time and cost of conventional research. Market Mapping delivers powerful, precise techniques for turning crude, unshaped geographic data - telephone numbers, ZIP codes, addresses, population statistics, and more - into polished sales and marketing intelligence. This user-friendly guide evaluates the features and capabilities of today's most important mapping software - MapInfo, ARC/INFO, Tactician, Scan/U.S., Descartes, Atlas MapMaker, Atlas Pro, Atlas GIS, and other programs. It clearly explains how to create stunning, high-impact graphics and easily interpret this output. And it gives readers looking to go global the ability to access worldwide data sources for marketing decisions. Packed with numerous illustrations, comprehensive listings of demographic data sources, and engaging, hands-on case studies of actual marketing scenarios, Market Mapping shows you how to detect marketing trends and relationships often concealed by spreadsheets and conventional database reports; channel advertising dollars to media with different demographics; determine optimal product mixes for different sales regions; find new, more profitable retail locations; target and track successful direct-mail campaigns; and effectively reorganize a sales force. Market Mapping comes complete with glossary, p

Comparing MVS and UNIX Security: The View from the Glass House

For years, the mainstay of corporate computing has been the centralized mainframe—a behemoth caged in a climate-controlled glass house. In most cases, this mainframe is an IBM or IBM-compatible computer running the MVS operating system and operating as either a standalone system or as part of a limited, proprietary network of mainframes within the same organization. Security on these mainframe systems has improved over time, as management has come to understand its importance and as vendors have developed and marketed access control software that is both effective and easy to use. For example, most of these systems operate with one of the major access control packages (IBM's RACF or Computer Associates' CA=ACF2 or CA=Top Secret).

Data on demand

PSE&G provides timely energy management system (EMS) data throughout the corporation using its computer system's extensive networking capability, which allows direct local area network and wide area network (LAN/WAN) ties. The EMS has links to production support systems, corporate mainframe systems, and to the PC LAN system. These nets are connected together using transport control protocol and Internet protocol (TCP/IP).< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Building an Automated Security Monitor

No company can survive in the 1990s without the ability to rapidly access information from remote locations. Remote access unfortunately creates new opportunities to penetrate computer systems. It is not unusual for an Internet host owner to find that an unauthorized person has been browsing sensitive files. Hackers can hit hundreds of systems at once, pulling information back to an intermediate location for analysis. Although the hacking of mainframes is less common than that of micro- and minicomputers, it is still an important concern, given that by one estimate, 80% of all critical corporate data is stored on IBM mainframe systems. In response to these threats, a security manager may spend years implementing rigorous policies and controls for routine system auditing and violation reporting. Yet, in an ever-changing environment, how can the security manager be assured that these controls really work to protect critical information? Demand for quick system access and remote use continues to chip away at the fortresses we have built.

A methodology for the manufacture of forming tools incorporating complex surface geometry with minimum computer resources

This paper presents a methodology for the manufacture of tools embodying true three-dimensional free-form surfaces using PC-based two-and-a-half axis CADCAM systems. The numerical control machining of free-form surfaces is usually accomplished utilizing minicomputer or mainframe computer aided design and manufacturing (CADCAM) systems. The resulting NC data are suitable for either three axis or five axis machining, dependent upon machine tool type/capability and CAM package complexity. However, the cost of such packages and systems precludes their use in smaller companies with only an occasional requirement for components embodying free-form surfaces. The increasing availability of powerful yet reasonably priced personal computers (PCs) coupled with improving software provides such companies with a far cheaper alternative approach. However, a common feature of PC-based CADCAM systems is that they are limited to two-and-a-half axis machining for all but special applications such as three axis canted Z-plane milling or four axis wire electro discharge machining. All the main functions performed on mainframe systems can be performed on personal computers, such as toolpath generation for free-form surfaces, cusp height determination and change in shape and volume which may be used for component springback compensation.

Performance analysis of client-server storage systems

The performance analysis of a system in which storage is provided by a file server node on a network of client processors is discussed. The server controls a hierarchy of storage devices, and provides all the necessary file management functions. The clients are large mainframe systems that have their own local storage devices. The movement of files among the various storage levels is managed by a hierarchical storage management system. A closed queuing network model of the client-server storage system is used to analyze the performance of the system for various file movement criteria and to study the tradeoffs between recalling a file and accessing it by a distributed file system. Several network topologies (Ethernet, token ring, channel-to-channel) and their effect on performance are considered.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Ameliorating the Pregnant Man problem: a verification tool for personal computer based expert systems

With the increase in expert systems development over the last several years, has come a need for verification tools that will allow the knowledge engineer to debug and refine the systems. Although some tools are forthcoming, these tools have traditionally been concerned with completeness and consistency checking of the knowledge base itself. Completeness and consistency checking are important aspects of knowledge base debugging, but there is another aspect that has been largely ignored, that is determining whether the expert system will ask the user foolish or useless questions. This aspect of knowledge base debugging is important, because a system that asks the user foolish or useless questions will quickly lose credibility, and when the credibility of an expert system is in question, it will be abandoned by its users. To address this problem, we developed a procedure to help the knowledge engineer determine whether the system will ask the user foolish or useless questions. This procedure is an iterative process based on identifying conflicting question pairs. It has identified four constructions in rule-based expert systems that lead to inappropriate questioning. This procedure is effective, easy to implement, and has exhibited benefits, which are not confined to identifying constructions in the knowledge base that lead to inappropriate questioning. As a result, this procedure should become a useful tool that can be used by knowledge engineers to build better, more error free expert systems. We developed and tested the procedure on personal-computer-based expert systems; we are not sure how it will scale to main-frame systems.

Integrating knowledge-based systems with mainframe data processing via terminal operator emulation

Abstract: The need to integrate knowledge-based systems (KBS) with mainstream data processing (DP) systems is increasingly recognised. It is also recognised that there is no ideal mode of KBS integration: different types of problem call for different modes of integration. Many large organisations are now facing a serious problem in the operation of their existing DP systems. This paper focuses on the problem of providing intelligent support to the (often inexperienced) terminal users of complex mainframe systems—but without initiating any significant changes to the existing DP environment. Over the past few years we have been attempting to evolve a solution to this type of problem that is satisfactory from both a human and a software engineering perspective. This paper outlines the previous work and considerations underlying our current approach. Starting from a purely mainframe-based mode of integration, this has entailed locating an increasing number of an integrated KBS-DP system's components onto a front-end workstation. In our current solution, both user interface and KBS modules reside on a workstation linked to the (unchanged) mainframe environment. The key element of this approach is terminal operator emulation: a KBS-controlled 'script’ facility on a workstation which emulates the flexible keyboard behaviour of an experienced mainframe terminal user interacting with an existing DP system. The software tools and techniques employed in implementing this solution are discussed and details of a large operational system are presented as an example application.

The server network generator (SNG)

The Server Network Generator (SNG) is a CASE tool that employs a problem solver's ability to represent an application as an ordinary block diagram, a graphical specification of its macroscopic structure. This functional decomposition provides a natural mechanism for subdividing the application into processing tasks that can be distributed across a computing network. Each "server" is a software process that assumes the role of one block in the diagram, performing one processing task, employing interprocess communication as indicated graphically. This approach differs from related research in its use of a functional decomposition in the application context, and its use of graphical programming of the application's macroscopic structure. A distributed network of IBM 7437 VM/SP Technical Workstations are shown as a powerful platform for problem solving, using the SNG as a CASE tool. Distributed computing models based upon networks of microprocessors have long been proposed as an alternative to centralized mainframe computing. The 7437 provides a genuine VM/370 computing environment, so that this approach to distributed computing allows large mainframe systems to be the most powerful nodes in the network, rather than attempting to replace them. A recently completed auxiliary processor is presented that was required to support interprocess communication via the shared-variable interface between virtual machines on different hosts.

The use of personal computers in hospital infection control

The storage, retrieval and analysis of hospital infection data is best performed by using computers. Many laboratory mainframe systems have infection control modules and there are some commercial programs for personal computers (PCs). An alternative is to use business and statistical PC software. Because of their large customer base these programs are reliable and easy to use yet extremely sophisticated and flexible, and they can be easily customized for use in infection control. Many combinations of software and hardware are available but the ones described here have been used successfully for several years at the Prince of Wales Hospital in Hong Kong.

Security policy

We frequently hear a lot about the need for security, indeed there are now security products on the market to more than protect most systems whether they be on mainframe, mini or microcomputer systems. While each of these products is usually designed to carry out a specific task, the way in which these controls are introduced is of prime importance as they are only a means to an end. All too often it is thought that all that is required is to introduce some piece of software or hardware and everything will be a bed of roses. In order to ensure that security is implemented in a controlled manner it is essential that there is a formal policy. What follows is my representations of what this policy should contain.

Organizational learning curve in software installation: An empirical investigation

Findings of an empirical investigation conducted to determine the presence of an organizational learning curve in the implementation of software packages for business applications are presented in this paper. Time spent by teams on the implementation of forty software packages on various mainframe, mini, and turnkey systems over a period of six years is analyzed. There is an organizational learning curve in the process of software implementation, and its magnitude varies from 6 to 36 percent. Higher rates of learning were observed for packages implemented on mainframes than those on mini-computers and turn-key systems. The paper suggests that these findings can be utilized for measuring and improving organizational productivity in the areas of software development and implementation and cost-benefit analysis of large systems projects.

Performance comparison of IO shipping and database call shipping: Schemes in multisystem partitioned databases

In a multi-system partioned database, the database is split between the multiple systems and a facility is provided to support the shipping of function requests among the systems. Two alternate levels of function requests, called IO request shipping and database call shipping, are analyzed and compared. The analysis is based on traces from large mainframe systems running IBM's IMS database management systems. A methodology is presented for deriving optimal database partitions and transaction assignment so as to minimize the average system response time. The methodology decomposes the optimization problem into an integer linear programming problem for partitioning the databases and a simplex reflection method for probabilistic transaction routing. The issues addressed include the effectiveness of routing and the limits of partitioning. The IO request shipping approach is preferable when high communications bandwidth is available as in a machine room. Furthermore, IO request shipping can take advantage of probabilistic routing to enhance its performance, while database call shipping gains little from probabilistic routing as compared to fixed routing. However, IO request shipping is more susceptible to lock contention which may become a problem for an environment with a high transaction rate. For systems with lower communications bandwidth spread beyond the machine room, the database call shipping approach is the method of choice.

Learning concepts of fractals and probability by “doing science”

Very recent advances in computer technology provide the power of mainframe systems in relatively compact and inexpensive personal computers; soon the computing power of even a supercomputer will be available on a desktop at a price comparable to today's personal computers. Over the next decade this tremendous computing power can and probably will become available in schools throughout the world. Here we discuss the possibility of harnessing this new technological resource as a teaching tool for specific topics in mathematics and science, focusing on random processes in nature and their deep connection to concepts in probability and fractal geometry. Such natural phenomena as the growth of snowflakes via random aggregation and the disordered geometric configurations of polymer chains demonstrate that fundamentally random microscopic processes can give rise to predictable macroscopic behaviors. They also give rise to random fractal structures of inherent interest and great beauty. Because it is impossible to view the underlying processes directly, computer simulation and visualization is an indispensable tool for understanding and studying these phenomena. In the process of “doing science” with both hands-on experiments and computer simulations, students would learn abstract mathematical concepts in a context which is at once concrete and inherently motivating. Furthermore, the techniques they could employ would mirror in most respects those in current use by researchers, thus forging an unprecedented link between this curriculum and the professional worlds of science and mathematics.

Multisystem coupling by a combination of data sharing and data partitioning

A hybrid architecture is proposed that combines the approaches of a multisystem partitioned database system and a data-sharing multisystem approach offering the advantages of each. With this architecture some databases are shared between systems, while others are retained private by specific systems. The authors examine how to determine which databases to share, which to retain private, and how to route transactions and partition the private databases among systems so as to minimize response time or overheads while balancing the load among systems. A simulated annealing heuristic is used to solve this optimizing problem. Trace data from large mainframe systems running IBM's Information Management System database management system are used to illustrate the methodology and to demonstrate the advantages of the hybrid approach. >

An Approach to the Low-Cost Computer Aided Manufacture of Components Embodying Free-Form Surfaces

The numerical control (NC) machining of free-form surfaces is usually accomplished utilizing minicomputer or mainframe computer aided design and manufacturing (C ADC AM) systems. The resulting NC data are suitable for either three-axis or five-axis machining dependent upon machine tool type/capability and CAM package complexity. However, the cost of such packages and systems precludes the use of these in smaller companies with an occasional requirement for components embodying free-form surfaces. The increasing availability of powerful yet reasonably priced personal computers (PC) coupled with improving software provides such companies with a far cheaper alternative approach. However, a common feature of PC-based CADCAM systems is that they are limited to 2 1/2-axis machining for all but special applications such as three-axis canted Z-plane milling of four-axis wire electro discharge machining (EDM). This paper presents a method for manufacturing true three-dimensional free-form surfaces using PC-based 2 1/2-axis CADCAM systems. All the main functions performed on mainframe systems can be performed on personal computers, such as toolpath generation for free-form surfaces, cusp height determination and change in shape and volume which may be used for the compensation of shrinkage or to suit market requirements. This is significant for manufacturers who make use of moulds, such as are found in the plastic processing industries. The manufacture of a blown plastic bottle mould is presented as a typical example. The inclusion into the PC environment of features to be found in mainframe systems is also discussed, such as machining the surface patch by patch in any direction or machining a number of patches at one time, shape and volume change in any direction, cusp height determination, etc.

Computer Technology Use by Louisiana Apparel Manufacturers

This study was designed to investigate computer technology use by Louisiana apparel manufacturers. The project stemmed from a growing supply of package software programs for apparel design and related apparel development/production functions intended for use with personal computers. Apparel manufacturers operating within the state were identified using a telephone survey to obtain information regarding current use of computer technology. Results indicated that, of the 43 companies identified, six of the firms operate under parent companies, while the remaining 37 are independently owned. Products made form a large array including sportswear, uniforms, dresses, and jeans in men's, women's, and children's sizes. The small to mid-sized companies, individually owned and still accomplishing many of their design/production functions manually, cannot afford to invest millions of dollars in mainframe or minicomputer systems. These companies are primary targets for assistance with computer technology transfer. Higher education can assist such firms to become more responsive to merchandisers with quick response.

Mini-micro-mainframe computer marriage: Combining technologies in a radiology results reporting system

The minicomputer-based information system in the Department of Radiology at the Medical College of Georgia Hospital and Clinics was placed in service in February, 1982. This system represents a sizable investment in minicomputer hardware in addition to more than 6 years of software customization. One serious deficiency in the original system was the lack of a radiology results reporting facility. Several options were considered to provide the department with this capability. The most obvious option was retiring the existing system and replacing it with one of a number of commercial products already offering results reporting. In-house development of a reporting facility lent itself more readily to microcomputers than to the existing minicomputer system. Due to system customization, economic and time constraints, it was decided to merge an in-house developed microcomputer-based report module into our existing minicomputer system. The minicomputer was able to communicate with and transfer files to and from both micro and mainframe systems. Combining technologies allowed us to continue taking advantage of our sizable investment in money, time, and customization while providing a microcomputer-based report module. Radiology reports are now typed on microcomputer word processors and bulk transferred to the minicomputer. The minicomputer provides access to both unapproved and approved reports on system terminals throughout the department. It also enhances reports by merging patient demographics and registration information. Using existing communications facilities to the hospital mainframe system, reports are provided throughout the institution.