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On-line upgrade of program modulesThis paper presents a taxonomy of problems that must be solved in order to achieve on-line upgradability of long-lived programs, and presents a solution to the fundamental problems in the taxonomy. The solutions are based upon AdaPT, a set of language extensions designed to aid in the distribution of a single Ada program. AdaPT introduces three major units, the public, the partition, and the node. Publics are primarily used to share type information. Partitions are the basic units of distribution while nodes are used to control the configuration of the program. Nodes and partitions can be created dynamically via the allocator. A node-level routine controls the replacement process. The controlling node creates a new instance of the routine being replaced; the run-time system must ensure that the new instance is the updated one. Once access to the new version has been established, all further calls to the module are redirected to the new version and the caller is informed of the change so that it may make subsequent calls directly. When a module is being upgraded, there is a transition period during which both the old and new versions are present. We require that clients of a potentially replaceable module 'check in' with the controlling node. The controlling node keeps track of the number of clients that have been redirected to the replacement. When all have been redirected, the old version can be deallocated.
Document ID
19940034849
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Waldrop, Raymond S.
(NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Volz, Richard A.
(NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Smith, Gary W.
(Texas A & M Univ. College Station, United States)
Holzbacher-Valero, A. A.
(NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Goldsack, S. J.
(Imperial College of Science Technology and Medicine, London, United Kingdom)
Date Acquired
August 16, 2013
Publication Date
January 1, 1993
Publication Information
Publication: In: AIAA Computing in Aerospace Conference, 9th, San Diego, CA, Oct. 19-21, 1993, Technical Papers. Pt. 2 (A94-11401 01-62)
Publisher: American Institute of Aeronautics and Astronautics
Subject Category
Computer Programming And Software
Report/Patent Number
AIAA PAPER 93-4621
Accession Number
94A11504
Funding Number(s)
CONTRACT_GRANT: NCC9-16
Distribution Limits
Public
Copyright
Other

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