System for protecting shared files in a multiprogrammed computer
First Claim
1. Apparatus for selectively permitting access to a related file of information by a candidate job step in a queue of job steps stored in preparation to be processed by a computing system, the related file including information related to the processing of said candidate job step by the computing system and information related also to the processing of an active job step currently being processed by the computing system, said apparatus comprising:
- (a) first means for storing a request file control manifestation associated with said candidate job step, said request manifestation including data identifying said related file of information, data identifying a set of requested rules which are to govern the sharing of said related file of information as said candidate job step is processed by the computing system, and data identifying a requested use to be made of said related file of information by said candidate job step;
(b) second means for storing a current-status file control manifestation, said current-status manifestation including data identifying said related file, data identifying a set of current rules governing the sharing of said related file of information, and data identifying a current use being made of said related file of information by said active job step currently being processed by the computing system;
(c) third means coupled to said first and second means for comprising said request control manifestation with said current-status control manifestation;
(d) fourth select control means coupled to said first and second means, for making a first determination whether the requested use as identified by the data of said request structure manifestation violates one of the current rules as identified by the data of said current-status manifestation, and for selectively permitting access to said related file of information by said candidate job step in accordance with said first determination;
(e) fifth select control means coupled to said first and second means, for making a second determination whether the current use as identified by the data of said current manifestation violates of the requested rules as identified by the data of said request manifestation, and for selectively permitting access to said related file of information by said candidate job step in accordance with said second determination; and
(f) sixth means coupled to said first and second means, for entering in said first means, when access to said related file by said candidate job step is granted in accordance with at least one of said first and second determinations of said fourth and fifth means, the requested rules as identified by said request manifestation as said current rules, and for entering in said second means said requested use as indicated by said request manifestation as said current use as identified by said current-status manifestation, thereby to determine the use by said candidate job step of said related file of information.
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Abstract
An arrangement for sharing file information among plural processes in a multiprogrammed computing system. Source program file declarations are compiled into file control structures which are placed in skeletal segments, the segments forming units of potential sharing between active processes. Those segments which contain file control structures are placed in either the address space of (1) all processes, (2) related processes, or (3) a single process, depending upon the declared sharing level of the file. Job control language (JCL) commmands are expanded into JCL file control structures and merged with the source language structures to form a file request control structure. This request may be compared against a catalog of existing external files, a check being made to insure that the account on whose behalf a computing job is requesting file assignment is authorized to obtain the requested access to the file. Further tests are then made to guarantee compatibility between the request and the current status of the file.
156 Citations
10 Claims
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1. Apparatus for selectively permitting access to a related file of information by a candidate job step in a queue of job steps stored in preparation to be processed by a computing system, the related file including information related to the processing of said candidate job step by the computing system and information related also to the processing of an active job step currently being processed by the computing system, said apparatus comprising:
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(a) first means for storing a request file control manifestation associated with said candidate job step, said request manifestation including data identifying said related file of information, data identifying a set of requested rules which are to govern the sharing of said related file of information as said candidate job step is processed by the computing system, and data identifying a requested use to be made of said related file of information by said candidate job step; (b) second means for storing a current-status file control manifestation, said current-status manifestation including data identifying said related file, data identifying a set of current rules governing the sharing of said related file of information, and data identifying a current use being made of said related file of information by said active job step currently being processed by the computing system; (c) third means coupled to said first and second means for comprising said request control manifestation with said current-status control manifestation; (d) fourth select control means coupled to said first and second means, for making a first determination whether the requested use as identified by the data of said request structure manifestation violates one of the current rules as identified by the data of said current-status manifestation, and for selectively permitting access to said related file of information by said candidate job step in accordance with said first determination; (e) fifth select control means coupled to said first and second means, for making a second determination whether the current use as identified by the data of said current manifestation violates of the requested rules as identified by the data of said request manifestation, and for selectively permitting access to said related file of information by said candidate job step in accordance with said second determination; and (f) sixth means coupled to said first and second means, for entering in said first means, when access to said related file by said candidate job step is granted in accordance with at least one of said first and second determinations of said fourth and fifth means, the requested rules as identified by said request manifestation as said current rules, and for entering in said second means said requested use as indicated by said request manifestation as said current use as identified by said current-status manifestation, thereby to determine the use by said candidate job step of said related file of information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification