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United States Patent (19) 11) Patent Number: 4,499,535 Bachman Et Al

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United States Patent (19) 11) Patent Number: 4,499,535 Bachman Et Al United States Patent (19) 11) Patent Number: 4,499,535 Bachman et al. (45) Date of Patent: Feb. 12, 1985 54) DIGITAL COMPUTER SYSTEM HAVING 3,821,711 6/974 Elam et al. .................. 340/347 DD DESCRIPTORS FORWARIABLE LENGTH 3,840,862 10/1974 Ready ................................. 364/200 ADDRESSING FOR A PLURALITY OF 4,050,058 9/1977 Garlic .......... ... 364/200 4,077,059 2/1978 Cordi et al. ......................... 364/200 INSTRUCT ON DIALECTS 4,084.226 4/978 Anderson et al. .................. 364/200 75 Inventors: Brett L. Bachman, Boston, Mass.; 4,136,386 1/1979 Annunziata et al. ............... 364/200 Richard A. Belgard, Saratoga, Calif.; 4,179,738 12/1979 Fairchild et al. ... ... 364/200 4,206,503 6/1980 Woods et al. ... ... 364/200 David H. Bernstein, Ashland; 4,210,960 7/1980 Borgerson ........................... 364/200 Richard G. Bratt, Wayland, both of 4,241,397 12/1980 Strecker et al. .................... 364/200 Mass.; Gerald F. Clancy, Saratoga, 4,241,399 12/1980 Strecker et al. .................... 364/200 Calif.; Edward S. Gavrin, Lincoln, Mass.; Ronald H. Gruner, Cary, OTHER PUBLICATIONS N.C.; Thomas M. Jones, Chapel Hill, N.C.: Craig J. Mundie; James T. Bit Sliced Microprocessor Architecture-Alexan Nealon, both of Cary, N.C.; John F. drides; IEEE Computer-Jun. 1978, pp. 56-81-L7904 Pilat, Raleigh, N.C.; Stephen I. 0001. Schleimer, Chapel Hill, N.C.; Steven Primary Examiner-Harvey E. Springborn J. Wallach, Saratoga, Calif. Attorney, Agent, or Firm-Joel Wall; Gene Nelson; Leonard Suchyta (73) Assignee: Data General Corporation, Westboro, Mass. (57) ABSTRACT (21) Appl. No.: 266,427 A digital computer uses a memory which is structured into objects, which are blocks of storage of arbitrary 22) Fled: May 22, 1981 length, in which data items are accessed by descriptors (51) Int. Cl. ........................... G06F 9/34; G06F 7/04 which for a desired data item specify the object, the (52) U.S. C. ................................................... 364/200 offset into that object, and the length of the data object. 58) Field of Search ... 364/200 MS File, 900 MS File; The computer system of the present invention further 340/347 DD provides the ability to execute any of a plurality of dialects of internal instructions, the repertoire of such 56) References Cited dialects being virtually infinite, since there is the ability U.S. PATENT DOCUMENTS to load a supporting microcode during operation as 3,388,381 6/1968 Prywes et al. ...................... 364/200 needed. 3,739,352 6/1973 Packard ...... ... 364/200 3,766,532 10/1973 Liebel .................................. 364/200 10 Claims, 1 Drawing Figure - - - - - - s OM - 12. JPP 42 S U.S. Patent Feb. 12, 1985 4499,535 4,499,535 1 2 arguments'. That is, users not having access rights to DIGITAL COMPUTER SYSTEM HAVING certain information have been able to gain access to that DESCRIPTORS FORWARIABLE LENGTH information through another user or procedure having ADDRESSING FOR A PLURALTY OF such access rights. INSTRUCTION DALECTS Yet another problem of the prior art is that of provid ing a simple and flexible interface user interface to a CROSS REFERENCE TO RELATED data processing system. The character of user's inter APPLICATIONS face to a data processing system is determined, in part, The present patent application is related to other by the means by which a user refers to and identifies patent applications assigned to the assignee of the pres O operands and procedures of the user's programs and by ent application. the instruction structure of the system. Operands and procedures are customarily referred to and identified by BACKGROUND OF THE INVENTION some form of logical address having points of reference, 1. Field of the Invention and validity, only within a user's program. These ad The present invention relates to a digital data pro 15 dresses must be translated into logical and physical cessing system and, more particularly, to a multiprocess addresses within a data processing system each time a digital data processing system suitable for use in a data program is executed, and must then be frequently re processing network and having a simplified, flexible translated or generated during execution of a program. user interface and flexible, multileveled internal mecha In addition, a user must provide specific instructions as nisms. to data format and handling. As such reference to oper 2. Description of Prior Art ands or procedures typically comprise a major portion A general trend in the development of data process of the instruction stream of the user's program and ing systems has been towards systems suitable for use in requires numerous machine translations and operations interconnected data processing networks. Another to implement. A user's interface to a conventional sys trend has been towards data processing systems 25 tem is thereby complicated, and the speed of execution wherein the internal structure of the system is flexible, of programs reduced, because of the complexity of the protected from users, and effectively invisible to the program references to operands and procedures. user and wherein the user is presented with a flexible A data processing system's instruction structure in and simplified interface to the system, cludes both the instructions for controlling system oper Certain problems and shortcomings affecting the 30 realization of such a data processing system have ap ations and the means by which these instructions are peared repeatedly in the prior art and must be overcome executed. Conventional data processing systems are to create a data processing system having the above designed to efficiently execute instructions in one or attributes. These prior art problems and limitations two user languages, for example, FORTRAN or CO include the following topics. 35 BOL. Programs written in any other language are not First, the data processing systems of the prior art efficiently executable. In addition, a user is often faced have not provided a system wide addressing system with difficult programming problems when using any suitable for use in common by a large number of data high level language other than the particular one or two processing systems interconnected into a network. Ad languages that a particular conventional system is de dressing systems of the prior art have not provided signed to utilize. sufficiently large address spaces and have not allowed Yet another problem in conventional data processing information to be permanently and uniquely identified. systems is that of protecting the system's internal mech Prior addressing systems have not made provisions for anisms, for example, stack mechanisms and internal information to be located and identified as to type or control mechanisms, from accidental or malicious inter format, and have not provided sufficient granularity. In 45 ference by a user. addition, prior addressing systems have reflected the Finally, the internal structure and operation of prior physical structure of particular data processing systems. art data processing systems have not been flexible, or That is, the addressing systems have been dependent adaptive, in structure and operation. That is, the inter upon whether a particular computer was, for example, nal structure structure and operation of prior systems an 8, 16, 32, 64 or 128 bit machine. Since prior data 50 have not allowed the systems to be easily modified or processing systems have incorporated addressing mech adapted to meet particular data processing require anisms wherein the actual physical structure of the ments. Such modifications may include changes in inter processing system is apparent to the user, the operations nal memory capacity, such as the addition or deletion of a user could perform have been limited by the address special purpose subsystems, for example, floating point ing mechanisms. In addition, prior processor systems 55 or array processors. In addition, such modifications have operated as fixed word length machines, further have significantly effected the users interface with the limiting user operations. system. Ideally, the actual physical structure and opera Prior data processing systems have not provided tion of the data processing system should not be appar effective protection mechanisms preventing one user ent at the user interface. from effecting another user's data and programs with 60 The present invention provides data processing sys out permission. Such protection mechanisms have not tem improvements and features which solve the above allowed unique, positive identification of users request described problems and limitations. ing access to information, or of information, nor have such mechanisms been sufficiently flexible in operation. SUMMARY OF THE INVENTION In addition, access rights have pertained to the users 65 The present invention relates generally to digital rather than to the information, so that control of access computer systems and more specifically to digital com rights has been difficult. Finally, prior art protection puter systems employing object-based addressing of mechanisms have allowed the use of "Trojan Horse data. The digital computer system of the present inven 4,499,535 3 4. tion includes a memory system including mass storage This application incorporates by reference the entire devices and one or more processors connected to the application, Ser. No. 266,402, filed on May 22, 1981, of memory system. Ward Baxter II et al. The memory system is organized into objects con More particularly, attention is directed to FIGS. 7, taining data items. Each data item is identified by a 102, 10, 202, 202A, 242, and 249 of the drawings in descriptor, which consists of three fields: the first speci application Ser. No. 266,402, and to that part of the fies the object in which the data item is to be found; the specification, particularly at pages 371-704 thereof, second specifies how far into that object the data item which relate to subject matter of the claims herein. begins; the third indicates the length of the data item.
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