Review of a New Data Management System for the Social Security Administration (1978) / Chapter Skim
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3. Technological Considerations
3. Technological Considerations
Pages 27-43
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From page 27... ...
These topics are examined here. INTERFACING AND MODELING The panel strongly supports the SSA planning group in its intentions to (1)
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From page 28... ...
Examples of such subsystems are the operation of the data base under various conditions; the flow of clients and workloads at a field office; and the operation of the nationwide communications network under a range of traffic loads. It will take expert judgment plus experimentation to select the appropriate techniques and adapt them to the situation.
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From page 29... ...
The panel, therefore, stops short -- but only a little short -- of recommending a switch to a revolutionary new scheme of model-based development. It supports, in particular, the plans for task and job modeling that have been developed in connection with the human factors test and evaluation facility, and it urges that major efforts be made in all of the following areas of modeling: 0 comparisons of alternative architectures, including various distributions and centralizations; · dynamic representation of process and system designs at various levels; modeling of human interaction, through terminals and hard copy, with the computer-communications system; communications network modeling;
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From page 30... ...
At the very least, a major modeling effort would put a great deal of the development work on-line in a large time-shared computer-an essential prerequisite for the successful prosecution of a large developmental program like that of the SSA. COMMON ICAT ION S SSA Communications Requirements The SSA's future communications requirements fall basically into the following four categories: · High-speed, high-capacity communications facilities between major computer/data base storage centers.
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From page 31... ...
· Procure raw facilities or services from common carriers and design and develop a configuration of its own communications network by procuring the appropriate terminal/communications processors, multiplex equipment, etc. As part of this option, different types of raw facilities would be considered, including digital facilities (DDS)
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From page 32... ...
The network design problem and the required technology associated with the SSA future system are comparable to those of several industrial organizations that have existing networks. New developments in the field of communications could, however, improve the future SSA process.
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From page 33... ...
@' Security considerations will be an important factor in the design of the communications system. Parse 1 Recommends t ion The future SSA commune cations network should be a widely dispel sea, sophisticated, highly interactive system that enables hi gh transmission reliability, minimum cost ~ adaptable lity to terminal and host equipment types, and flexibility in call set-up and data transport.
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From page 35... ...
· The cost of the communications system is not a dominant factor in the overall future system design and should not bias any major considerations, such as regionalized data base storage. The communications system design can be adapted to any concept without significant cost variations, particularly as related to the overall cost of this project.
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From page 36... ...
SSA may decide to design a minimal configuration for all offices, and to use standard enhancement features to achieve functional capability in excess of that provided by the basic work station. Current Status Today's available, off the shelf terminals range widely from simple hard copy typewriter devices to highly interactive cathode-ray tube displays.
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From page 37... ...
Data base and inquiry program products support a wide variety of display terminals. Access method, communications control, and network management programs are available so that users can concentrate upon developing application programs without having to acquire special talent for the specialized communications tasks.
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From page 38... ...
Extensive programming support, coupled with functions customized to the user and created by unique microcode, should further simplify incorporation of terminal stations into major computer networks. The most significant advances in display stations should come in color cathode-ray tube (CRT)
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From page 39... ...
The definition of functional requirements and the design of the programs that satisfy those requirements are much more intimately intertwined than is true in batch systems. This coupling must be explicitly defined in the initial development phase when functional requirements are being examined.
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From page 40... ...
In on-line systems, office operations and computer operations are so integrated that neither one can be performed efficiently without the other. Efficient organization of instructions within a computer program is for naught if the terminal operator does not understand what is expected.
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From page 41... ...
This can be minimized by making the original code simple and uniform. Maintainability will be enhanced by other factors as well: o Use of a single commonly employed high level computer language, such as COBOL.
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From page 42... ...
At the same time, the data processing services used by applications programs have become increasingly complex. Programs can be made obsolete not only by changes in functional requirements but also by changes in the hardware and system software environment in which the programs are executed.
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From page 43... ...
It is critical, therefore, that the managers of system software development be conscious of the existence of such tradeoffs and that the manner and reasons for resolving the matters be explicitly documented Accordingly, management must stipulate the ob jectives of the process and their interrelationships. It must also employ sampling techniques and other tools of quality assurance and performance measurement both during and after the development period to ensure that the objectives are both understood and realized.
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