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S.2.4 MAGNETIC TAPE
Creators of STI data bases also have a requirement for magnetic tape units as well as the on-line search services. Magnetic tape is a sequential storage medium; that is, to locate information, the entire tape may need to be read. Even with a high speed tape drive, this process can average 2-5 minutes. This is not suitable for on-line searching, whereas a disc can locate information with 75 msec. Magnetic tape is more often used for archival storage as its price is less, and the capacity, depending upon the tape, is nearly equal. Older editions of the data base can be conveniently stored on magnetic tape. Two other uses are made of magnetic tape editions of the data base. First, data base copies are usually maintained in case the on-line data base is accidently destroyed or damaged. Second, a magnetic tape is easier to ship to STI data base leasors than a disc. Discs are more fragile and require careful packing to insure against damage.
S.2.5 HIGH SPEED PRINTERS
A high speed printer is usually found at most computer facilities, including those which contain STI data bases. They serve two main purposes: First, to provide a hard copy of information from STI systems when the volume is large or the user has no hard copy capabilities of his own. Additionally, the maintenance of the data base may involve a detailed examination of portions of the data base. In these instances, a hard copy is more useful than access through a CRT.
Other computer hardware may also be found at an STI facility. Data communications equipment such as modems, front-end processors, and multiplexers which allow remote users to access the STI data bases, will be found where on-line search services are offered.
In addition to computer hardware, software is also required to control and search for information contained within STI data bases. Software can be defined as the programs that direct computers to perform specific functions. A software package is a computer program or set of programs designed to perform one or more well defined functions. Of concern to this discussion are mainly the "systems package." Systems packages are programs or sets of programs that make it possible to use a computer more conveniently or operate it more effectively. Included in this category are both operating systems and data base management systems.
The operating system, sometimes called the executive, manages the computer resources and permits the user to interact with the system. Initial access to a STI on-line system is under the control of the operating system. Almost all user-oriented systems have an operating system; however, in the case of STI systems, limits are placed upon what the user may do. For example, unlike timesharing computer systems, the user cannot create his own programs or modify the stored data bases. In a STI environment, the user can gain access only to STI data bases and issue commands relevant to the use of the computer for access or search of the data base.
Once an appropriate STI data base is selected for searching, the user is placed under control of a data base management system (DBMS). It is the DBMS that actually examines the data base to determine if the user's specified parameters can be matched by the stored information within a STI system.
The method of operation while under the control of a DBMS system in a STI environment is to define identifiers or descriptors upon which a search is based. Examples of descriptors are:
Searching can be quite complex according to the sophistication of the user and the DBMS system.
Figure I is a functional schematic of a STI facility and shows the layout and interconnection of the hardware.
In order to limit the discussion of STI systems, we will confine ourselves to describing the services offered by on-line search services. Figure II contains a description of the STI data bases offered. The information contained within each data base is limited to descriptive information of articles published in scientific and technical journals. Some data bases contain brief abstracts of the articles cited. At
Is complete single source reference to more than 1500 grant programs offered by federal, state and local governments, commercial organizations, associations and private foundations in over 88 disciplines, including adult education, agriculture, social sciences, fine arts, architecture, natural sciences, banking and business, health sciences, and law. Prepared by Oryx Press. (Operational January, 1977)
Covers business management periodical literature from over 300 journals, in the areas of finance, management, economics, statistics, business law, and marketing. Journals such as Duns Review, Harvard Business Review, and Nations Business are abstracted. Prepared by ABI, a division of Data Courier, Inc.
Covers English-language materials in all subject areas of the monographic literature and audiovisual materials, and includes MARC records from the Library of Congress as well as many more LC-cataloged items.
Same as LIBCON/E, but covers non-English-language materials.
Is a broad and cross-disciplinary file containing citations and abstracts of government-sponsored R&D reports and other government analyses prepared by Federal agencies or their contractors and grantees. Corresponds to the Weekly Government Abstracts and the semimonthly Government Reports Announcements. Prepared by National Technical Information Service (NTIS) of the U.S. Department of Commerce.
TYPICAL STI DATABASES
present, no full-textual materials are stored by on-line search services. The reason is both technological and economic. The on-line storage capacity required for complete textual storage of all scientific and technical journals currently indexed by STI data bases would be very large. Information is largely alphabetic characters, which at present, are not efficiently stored by current computer technology. Economically, the cost of operations would increase substantially. In addition, the utilization of the computer storage resources would decrease, due to the existence of stored texts that might be accessed on an infrequent basis. The computer-based information system which is based on high speed data manipulation and an ability to perform repetitive iterations on large volumes of information does not function weil in an environment which demands large storage capacities.
After review of the collected information of new technologies and copyright and computerized STI systems, we have determined that three characteristics of computerized STI systems merit further discussion. They are the development of:
Without these three technological enhancements to computers, the possibility of computerized STI system would have been too costly to operate and too difficult to manage. Together, these mechanisms provided the users of STI systems with a methodology that made more information available, at a faster speed, and with a decrease of human resources.
In comparing these innovations, specifically in the area of STI systems, it is helpful to consider the library as the opposite extreme of a computerized STI system. Given a sufficiently large library with adequate resources, the results of a scientific search would be similar to that accomplished by a computerized STI system.
A library, where a literature search is conducted of relevant journals, is an inherent part of the scientific and technological method. To satisfy the researcher's need to obtain information, he could either browse through the library stacks or rely upon extracting information sources from compilations of abstracts of scientific journal (i.e., chemical abstracts). The process required considerable time as the