GESAL(ID:3072/ges001)General Electric Symbolic Assembly LanguageGeneral Electric Symbolic Assembly Language Places Related languages
References: in Automatic Coding, Monograph No. 3, Journal of the Franklin Institute Philadelphia, Pa., April 1957. view details The organization has operated on a cooperative basis, establishing a standard language of communication and exchanging a large number of programs which form the tools for effectively using the computer. This standard language of communication is that used in the SHARE Assembly Program, which was developed by United Aircraft Corporation and patterned after the first such program for the 704 which was developed under the writer's direction by the General Electric Company. This, in turn, was patterned to a considerable extent after the "Comprehensive System" which was pioneered at M. I. T. for use on the Whirlwind computer. At the SHARE meeting held in December 1956, the organization anticipated the forthcoming IBM 709 which was similar in a great many respects to the machine around which the organization was originally built. In order to have a set of programs available for use upon delivery of the new machine, the organization established a 709 System Committee which was given the task of preparing a “system” for using the machine. The writer was made Chairman of this Committee. Various installations volunteered individuals for service on this committee on a full time basis. The following people were selected by the Committee Chairman and the SHARE Executive Board for participation on the committee: Donald L. Shell General Electric Co., Cincinnati, O., Chairman Elaine M. Boehm IBM, New York Ira Boldt Douglas Aircraft Corp., Santa Monica Harvey Bratman Lockheed Aircraft Corp., Los Angeles Vincent DiGri IBM, New York Irwin D. Greenwald Rand Corporation, Santa Monica Maureen E. Kane IBM, Poughkeepsie Jane E. King General Electric Co., Schenectady Owen R. Mock North American Aviation, Los Angeles Stanley Poley Service Bureau Corp., New York Thomas B. Steel System Development Corp., Santa Monica Charles J. Swift Convair, San Diego The Committee's work led to the creation of a system which has been named SCAT (for SHARE Compiler, Assembler, Translater). The initial problem facing the committee was to define what was meant by a system. The scope of the anticipated system varied greatly in the minds of the various members of the committee. After due consideration, it was decided to specify a complete installation operational system with all the fundamental necessities for effective machine utilization supplied. The committee would use the best experience available and advance the art of machine usage, if possible. However, it would not attempt any features of such novelty as to endanger completion of the system in the time available. Some of the objectives sought were: simplicity nonstop machine operation card-tape input interchangeability minimum programmer constraints automatic error detection ability to handle the SHARE 704 language, wherever possible. The most important advance made in the system over previous developments is in the area of program debugging. It was felt by the committee that if any true advancement were to be made in this direction, especially in higher language coding situations, it would be necessary to make the machine reply to the programmer in the same language that the programmer originally used to code his problem. The ability to perform this very desirable feat has not been accomplished in every instance. However, a rather long step has been taken in this direction. This step was made possible through the use of symbolic machine language, patterned closely after the SHARE 704 language, as the common denominator for all communication with the machine. Instructions written in symbolic form, as macro instructions,1 as algebraic statements, as subroutines or in any other acceptable form, are converted to symbolic machine language by the compiler and retained in an encoded symbolic form as the compiled version of the program. This encoded form of the program is called the SQUOZE deck. Thus, the symbolic machine language is used for compiler output. It is also used for communicating program changes and corrections at execution time and even for debugging output. This use of the symbolic language is, we feel, a major forward step in the techniques of machine utilization.A rather generalized picture of system usage is illustrated in figure 1. The men pictured there are actually the same person (the programmer) at different points in the system. Initially, at the upper left, he supplies his programs. These go to the compiler, C, in various formats—symbolic instructions, macro instructions, library subroutines, previously compiled SQUOZE decks, and perhaps ultimately FORTRAN statements. The compiler processes this material to produce a single SQUOZE deck which may now be passed along to the modify and load, L, portion of the system. The loading procedure accepts, along with the compiler output, corrections and modifications directly from the programmer in the same symbolic language used to write the original program. Whereas the compiler and loading procedures operate separately from the object program, the input, I, output, O, and debugging, D, systems are in essence attachments to the object program. These routines absorb the bulk of the burden of translation for the programmers. A set of fundamental routines are provided in a very flexible form—easily adapted to the specific needs of any particular problem. This whole procedure makes possible some very important advantages. First of all, one can make corrections in the same symbolic language in which the program was originally written. Thus, it is a simple matter to keep the program continuously up-to-date. Secondly, the machine has available at execution time sufficient information for the inverse translation—from absolute to symbolic machine language. Thirdly, it is possible to leave many program parameters undefined until execution time, which by former methods had to be defined at compile time. Further details as to methodology and procedure are outlined in the other papers of this set.Three methods were available for the development of this system: The 709 System Committee could assume complete responsibility for the system, including program coding and checkout. The Committee could completely specify the system and SHARE members would volunteer to produce component programs for the system. The Committee could specify the system, whereas coding and checkout would be done by the manufacturer. The planning effort expended by the committee amounted to about five man years. This, as can readily be seen, is a very large amount of planning time for such a system. A considerable number of alternative ideas were investigated and developed to some extent before being discussed and either discarded or finally adopted as part of the system. Since there were a number of rather divergent points of view represented in the committee, it took a great deal of effort to reconcile these approaches into a unified working whole. In addition to the Committee effort, the manufacturer has spent between ten and fifteen man years in order to implement the system. This time has been spent in detailed specifications analysis, programming, coding, checkout, and system integration. The completed system will contain about 46,000 words of instructions and tables. About 13,000 words of this total are needed for the compiler. The remainder is used for the modify and load program, the input and output translation systems, the debugging system and the supervisory control system. About 1,000 words of memory will be needed by the system at execution time. A considerable body of experience will be required before this effort can be properly evaluated. However, we shall here set forth a tentative evaluation. First of all, an excellent machine utilization system has been devised. It is a system which should be generally acceptable to all of the users of this particular machine. It has been recognized from the beginning that many local installations will wish to make changes and improvements in the system in order to adapt it especially to their needs. However, the fundamental procedures used throughout the system will undoubtedly be retained in every installation. In particular, the basic foundation, the encoded symbolic language, can and will be used as a common language from one installation to another and will serve as an excellent communication device. It is the writer's feeling that the planning took more effort than was really necessary to produce such a system. This was due in large measure to the enforced inefficiencies of committee action; particularly a committee which is supposed to reconcile many divergent points of view and which does not have a really effective decision procedure. Viewed in this light, it would appear that the very excellent talent which made up the Committee was not used in the most effective possible way. On the other hand, probably all the Committee members will agree that the final result is a better system than any one of the members would have developed completely on his own. Furthermore, it was obtained with a smaller expenditure of effort by any one installation than would have been necessary to develop any reasonable working system. Viewed in this light, it would appear that although these individuals may not have been operating in the most effective way, still the various installations which contributed these people are getting more for their money than they would have obtained by having them work at home for the same period of time. In addition, future communication of programs among the members of SHARE will be greatly enhanced and expedited through the use of this language which is common to all. These results have made the whole effort extremely worthwhile. in [ACM] JACM 6(2) April 1959 view details [321 programming languages with indication of the computer manufacturers, on whose machinery the appropriate languages are used to know. Register of the 74 computer companies; Sequence of the programming languages after the number of manufacturing firms, on whose plants the language is implemented; Sequence of the manufacturing firms after the number of used programming languages.] in [ACM] JACM 6(2) April 1959 view details The exact number of all the programming languages still in use, and those which are no longer used, is unknown. Zemanek calls the abundance of programming languages and their many dialects a "language Babel". When a new programming language is developed, only its name is known at first and it takes a while before publications about it appear. For some languages, the only relevant literature stays inside the individual companies; some are reported on in papers and magazines; and only a few, such as ALGOL, BASIC, COBOL, FORTRAN, and PL/1, become known to a wider public through various text- and handbooks. The situation surrounding the application of these languages in many computer centers is a similar one. There are differing opinions on the concept "programming languages". What is called a programming language by some may be termed a program, a processor, or a generator by others. Since there are no sharp borderlines in the field of programming languages, works were considered here which deal with machine languages, assemblers, autocoders, syntax and compilers, processors and generators, as well as with general higher programming languages. The bibliography contains some 2,700 titles of books, magazines and essays for around 300 programming languages. However, as shown by the "Overview of Existing Programming Languages", there are more than 300 such languages. The "Overview" lists a total of 676 programming languages, but this is certainly incomplete. One author ' has already announced the "next 700 programming languages"; it is to be hoped the many users may be spared such a great variety for reasons of compatibility. The graphic representations (illustrations 1 & 2) show the development and proportion of the most widely-used programming languages, as measured by the number of publications listed here and by the number of computer manufacturers and software firms who have implemented the language in question. The illustrations show FORTRAN to be in the lead at the present time. PL/1 is advancing rapidly, although PL/1 compilers are not yet seen very often outside of IBM. Some experts believe PL/1 will replace even the widely-used languages such as FORTRAN, COBOL, and ALGOL.4) If this does occur, it will surely take some time - as shown by the chronological diagram (illustration 2) . It would be desirable from the user's point of view to reduce this language confusion down to the most advantageous languages. Those languages still maintained should incorporate the special facets and advantages of the otherwise superfluous languages. Obviously such demands are not in the interests of computer production firms, especially when one considers that a FORTRAN program can be executed on nearly all third-generation computers. The titles in this bibliography are organized alphabetically according to programming language, and within a language chronologically and again alphabetically within a given year. Preceding the first programming language in the alphabet, literature is listed on several languages, as are general papers on programming languages and on the theory of formal languages (AAA). As far as possible, the most of titles are based on autopsy. However, the bibliographical description of sone titles will not satisfy bibliography-documentation demands, since they are based on inaccurate information in various sources. Translation titles whose original titles could not be found through bibliographical research were not included. ' In view of the fact that nany libraries do not have the quoted papers, all magazine essays should have been listed with the volume, the year, issue number and the complete number of pages (e.g. pp. 721-783), so that interlibrary loans could take place with fast reader service. Unfortunately, these data were not always found. It is hoped that this bibliography will help the electronic data processing expert, and those who wish to select the appropriate programming language from the many available, to find a way through the language Babel. We wish to offer special thanks to Mr. Klaus G. Saur and the staff of Verlag Dokumentation for their publishing work. Graz / Austria, May, 1973 in [ACM] JACM 6(2) April 1959 view details Resources
|