rfc707.txt

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NWG/RFC# 707                                  JEW 14-JAN-76 19:51  34263
NCC 76         A High-Level Framework for Network-Based Resource Sharing
            Appendix D:  A Look at Some Possible Extensions to the Model



APPENDIX D:  A LOOK AT SOME POSSIBLE EXTENSIONS TO THE MODEL          10

   The result of the distributed-system-building strategy proposed
in the body of this paper and the preceeding appendices is depicted
in Figure D-1.  At the core of each process is the inter-process
communication facility provided by the operating system, which
effects the transmission of arbitrary binary data between distant
processes.  Surrounding this core are conventions regarding first
the format in which a few, primitive types of data objects are
encoded in binary for IPC, and then the formats of several composite
data objects (that is, messages) whose transmission either invokes
or acknowledges the previous invocation of a remote procedure.
Immediately above lies an open-ended protocol layer in which an
arbitrary number of enhancements to the distributed programming
environment can be implemented.  Encapsulating these various
protocol layers is the installation-provided run-time environment,
which delivers DPS services to the applications program according to
machine- and possibly programming-language-dependent conventions.    10a

   The Protocol proposed in the present paper recognizes only the
most fundamental aspects of remote procedure calling.  It permits
the caller to identify the procedure to be called, supply the
necessary arguments, determine the outcome of the procedure, and
recover its results.  In a second paper [19], the author proposes
some extensions to this simple procedure call model, and attempts to
identify other common forms of inter-process interaction whose
standardization would enhance the distributed programming
environment.  Included among the topics discussed are:               10b

   (1) Coroutine linkages and other forms of communication between
       the caller and callee.                                       10b1

   (2) Propagation of notices and requests up the thread of control
       that results from nested procedure calls.                    10b2

   (3) Standard mechanisms for remotely reading or writing
       system-global data objects within another program.           10b3

   (4) Access controls for collections of related procedures.       10b4

   (5) A standard means for creating and initializing processes,
       that is, for establishing contact with and logging into a
       remote machine, identifying the program to be executed, and
       so forth.  This facility would permit arbitrarily complex
       process hierarchies to be created.                           10b5






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NWG/RFC# 707                                  JEW 14-JAN-76 19:51  34263
NCC 76         A High-Level Framework for Network-Based Resource Sharing
            Appendix D:  A Look at Some Possible Extensions to the Model



   (6) A mechanism for introducing processes to one another, that
       is, for superimposing more general communication paths upon
       the process hierarchy.                                       10b6

These and other extensions can all find a place in the open-ended
protocol layer of Figure D-1.  The particular extensions explored in
[19] are offered not as dogma but rather as a means of suggesting
the possibilities and stimulating further research.                  10c











































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NWG/RFC# 707                                  JEW 14-JAN-76 19:51  34263
NCC 76         A High-Level Framework for Network-Based Resource Sharing
                                                              References




REFERENCES                                                            11

 1. Kahn, R. E., "Resource-Sharing Computer Communications
    Networks," Proceedings of the IEEE, Vol. 60, No. 11, pp.
    1397-1407, November 1972.                                        11a

 2. Crocker, S. D., Heafner, J. F., Metcalfe, R. M., Postel, J. B.,
    "Function-oriented Protocols for the ARPA Computer Network,"
    AFIPS Proceedings, Spring Joint Computer Conference, Vol. 40,
    pp. 271-279, 1972.                                               11b

 3. Carr, C. S., Crocker, S. D., Cerf, V. G., "Host-Host
    Communication Protocol in the ARPA Network," AFIPS Proceedings,
    Spring Joint Computer Conference, Vol. 36, pp. 589-597, 1970.    11c

 4. Mc Kenzie, A. A., Host/Host Protocol for the ARPA Network, Bolt
    Beranek and Newman Inc., Cambridge, Massachusetts, January 1972
    (SRI-ARC Catalog Item 8246).                                     11d

 5. Walden, D. C., "A System for Interprocess Communication in a
    Resource Sharing Computer Network," Communications of the ACM,
    Vol. 15, No. 4, pp. 221-230, April 1972.                         11e

 6. Cerf, V. G., Kahn, R. E., "A Protocol for Packet Network
    Intercommunication," IEEE Transactions on Communications, Vol.
    Com-22, No. 5, pp. 637-648, May 1974.                            11f

 7. Thomas, R. H., "A Resource-Sharing Executive for the ARPANET,"
    AFIPS Proceedings, National Computer Conference, Vol. 42, pp.
    155-163, 1973.                                                   11g

 8. TELNET Protocol Specification, Stanford Research Institute,
    Menlo Park, California, August 1973 (SRI-ARC Catalog Item
    18639).                                                          11h

 9. Engelbart, D. C., Watson, R. W., Norton, J. C., "The Augmented
    Knowledge Workshop," AFIPS Proceedings, National Computer
    Conference, Vol. 42, pp. 9-21, 1973.                             11i

10. Engelbart, D. C., English, W. K., "A Research Center for
    Augmenting Human Intellect," AFIPS Proceedings, Fall Joint
    Computer Conference, Vol. 33, pp. 395-410, 1968.                 11j

11. Irby, C. H., Dornbush, C. F., Victor, K. E., Wallace, D. C., "A
    Command Meta Language for NLS," Final Report, Contract





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NWG/RFC# 707                                  JEW 14-JAN-76 19:51  34263
NCC 76         A High-Level Framework for Network-Based Resource Sharing
                                                              References




    RADC-TR-75-304, SRI Project 1868, Stanford Research Institute,
    Menlo Park, California, December, 1975.                          11k

12. Neigus, N. J., File Transfer Protocol, ARPA Network Working
    Group Request for Comments 542, Bolt Beranek and Newman Inc.,
    Cambridge, Massachusetts, July 1973 (SRI-ARC Catalog Item
    17759).                                                          11l

13. Bressler, R. D., Guida, R., Mc Kenzie, A. A., Remote Job Entry
    Protocol, ARPA Network Working Group Request for Comments 360,
    Dynamic Modeling Group, Massachusetts Institute of Technology,
    Cambridge, Massachusetts, (undated) (SRI-ARC Catalog Item
    12112).                                                          11m

14. Watson, R. W., Some Thoughts on System Design to Facilitate
    Resource Sharing, ARPA Network Working Group Request for
    Comments 592, Augmentation Research Center, Stanford Research
    Institute, Menlo Park, California, November 20, 1973 (SRI-ARC
    Catalog Item 20391).                                             11n

15. White, J. E., DPS-10 Version 2.5 Implementer's Guide,
    Augmentation Research Center, Stanford Research Institute, Menlo
    Park, California, August 15, 1975 (SRI-ARC Catalog Item 26282).  11o

16. White, J. E., DPS-10 Version 2.5 Programmer's Guide,
    Augmentation Research Center, Stanford Research Institute, Menlo
    Park, California, August 13, 1975 (SRI-ARC Catalog Item 26271).  11p

17. White, J. E., DPS-10 Version 2.5 Source Code, Augmentation
    Research Center, Stanford Research Institute, Menlo Park,
    California, August 13, 1975 (SRI-ARC Catalog Item 26267).        11q

18. Bobrow, D. G., Burchfiel, J. D., Murphy, D. L., Tomlinson, R.
    S., "TENEX, a Paged Time Sharing System for the PDP-10,"
    Communications of the ACM, Vol. 15, No. 3, pp. 135-143, March
    1972.                                                            11r

19. White, J. E., "Elements of a Distributed Programming System,"
    Submitted for publication in the Journal of Computer Languages,
    1976.                                                            11s










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NWG/RFC# 707                                  JEW 14-JAN-76 19:51  34263
NCC 76         A High-Level Framework for Network-Based Resource Sharing
                                                             Figure List




FIGURE LIST                                                           12

Figure   1.  Interfacing a remote terminal to a local time-sharing
             system via the TELNET Protocol.                         12a

Figure   2.  Interfacing distant applications programs via their
             run-time environments.                                  12b

Figure D-1.  Software and protocol layers comprising a process
             within the distributed programming system.              12c








































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NWG/RFC# 707                                  JEW 14-JAN-76 19:51  34263









     A High-Level Framework for Network-Based Resource Sharing














                             23-DEC-75
                                  
                           James E. White
                    Augmentation Research Center
                                  
                    Stanford Research Institute
                   Menlo Park, California  94025
                                  
                        [phone] x2960
                                  
                                  
                                  
                                  
                                  
      This paper proposes a high-level, application-independent
   protocol and software framework that would extend the local
   programming environment to embrace modules in other computers
   within a resource sharing computer network, and thereby
   facilitate the construction of distributed systems and encourage
   the sharing of resources.

      The work reported here was supported by the Advanced Research
   Projects Agency of the Department of Defense, and by the Rome Air
   Development Center of the Air Force.

      This paper has been submitted for publication in the
   Proceedings of the 1976 National Computer Conference.