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CONCOMP: Conversational Use of Computers
NECESSITY, THE MOTHER OF INVENTION: MTS and the DATA CONCENTRATOR
From page 1 of the U-M Computing Center Newsletter, Volume 1, Number 4, 8 March 1971: The Computing Center's IBM System/360 Model 67 was delivered in January 1967, and since that time the hardware has proven itself to be as versatile as we had anticipated. However, IBM's operating system for the 360/67, known as TSS (Timesharing System), was not available on that date, and, when finally available, its performance was not adequate to discharge effectively the demands placed upon it by the great diversity and large number of University users. In addition, there was not available as standard IBM equipment a "terminal controller" which would permit effective communication between the central computer and interactive terminals having widely varying performance characteristics. These two shortcomings placed a particularly awesome burden on the Concomp Project: Research in Conversa- tional Use of Computers, a multimillion dollar project funded by the Advanced Research Projects Agency of the Department of Defense to study the wide range of topics implied by its title. This Project (recently terminated) began in August 1965, and was predicated on the avail- ability of both TSS and the terminal controller. Thus the Computing Center and the Concomp Project found themselves involved in two large research tasks that they had not anticipated: (1) the development of an oper- ating system for the central computing facility that would support any type of effective man-machine interaction, and (2) the development of an effective hardware interface to support a wide range of terminal devices. The successful resolution of the first problem by the Computing Center resulted in the operating system known as MTS (Michigan Terminal System). Mr. Michael Alexander of the senior staff was its chief "architect." MTS now serves more than 9,000 active users, and is a single unified system for both interactive terminal use and batch processing. A typical demand peak finds fifty to sixty active terminals and four to six batch streams operating concurrently. The success of MTS is attested to by its adoption by a number of other universities: Wayne State University in the U.S.A., Newcastle-upon-Tyne in the U.K., Grenoble (France), and the universities of Alberta and British Columbia (Canada). Remote terminals using MTS may range from the ultimate low cost and simplicity of the pushbutton, or Touch-Tone, telephone, through the numerous low-speed alphanumeric terminals (both cathode-ray-tube and impact printers) and storage-tube graphic displays, to the more versatile remote graphics terminals. Moveover, the facilities for conversational conputation provided under MTS are suf- ficiently general to permit their extension to many other areas not originally proposed-for example, MTS provides unusually flexible remote-job-entry facilities as well as interaction between the central computer and remote mini- computers in a variety of laboratory digital/analog control systems. The lack of adequate terminal controller hardware for interfacing diverse remote-access terminals with the System 360 hardware led to the design, development, and fabrica- tion under the Concomp Project of a very generalized data communications terminal controller known as the Data Concentrator. It was inspired and implemented by Mr. David Mills of the Computing Center's senior staff. The generality of the Data Concentrator stems from the fact that it is programmable, its principal component being a small general-purpose computer, the DEC PDP-8. This means that its designers can program the Data Concentrator to accept a variety of terminal of different manufacture and different operating characteristics. This fact, coupled with other characteristics of the Data Concentrator, has made it possible for the Computing Center to respond to the evolving remote-terminal requirements of its user com- munity. In addition to adaptability, the Data Concentrator is characterized by communications protocols which facilitate interactive use of MTS. The development of the Data Con- centrator's communications protocol and general organiza- tion served in part as the basis for subsequent development of computer networks, such as the ARPA network and the MERIT Computer Network; and the hardware designs have influenced the construction of several contemporary machines which will be used to interconnect the major computers in the MERIT network. According to F. H. Westervelt, formerly Associate Director of the UM Com- puting Center and now Director of Wayne State's Computer and Data Processing Center, "The flexibility of the Data Concentrator in responding to a dynamically changing en- vironment of line speeds, code frames, code conversions, line controls, and device-support requirements is still un- matched in any commercially available equipment." The success of the Data Concentrator, coupled with its ever increasing use by greater numbers and varieties of terminals, led to the recent decision to begin construction of a second Data Concentrator, this time based on a PDP-8E and a PDP-11 computer. These are machines of a newer generation than the old PDP-8, and they are ex- pected to accommodate more adequately the anticipated increased demands for Data Concentrator facilities. |
CONCOMP papers and reports online
The following papers and reports are available online:
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CONCOMP Project Publications, 6 September 1971
This Newsletter Supplement appeared as part of the U-M Computing Center Newsletter, Volume 1, Number 12, 6 September 1971: |
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