JPS6242245A - File access method - Google Patents

Abstract

PURPOSE:To give the priority to an access request whose processing is desired at an early state by carrying out the control for each access together with the priority and giving the access preferentially to the process to which the early execution is desired. CONSTITUTION:When an access request 5 is given to a file 1 via a process B3, a lock mechanism 4 gives the permission 6 to the process B3 since no other access request is given to the file 1. Then an access request 8 is delivered via a process A2 during the access of the process B3. Thus the mechanism 4 knows the access mode of the process B3 and accepts the request of the process A2 to wait 8 until the process B3 is unlocked. The mechanism 4 gives the access permission 11 to the process A2 even if an access request 10 is delivered as soon as the process B3 is unlocked since the process A2 has the request of higher priority. Thus the process B3 has to wait 12 until the process A2 is unlocked.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a file access method in a computer that processes multiple programs simultaneously, and a file access method when there are sometimes multiple access requests to the same file. .

[Conventional technology]

The conventional file access method is described in the magazine "Interface 4, July 1985, issue 498, pp. 259-p. 261, published by CQ Publishing. According to the conventional method, the program that issued the access request is File exclusive processing (lock processing) is performed at the same time as the access is completed, and unlock processing is performed when the access is completed.If a file is locked to process a certain access request, it will be unlocked from the point where the access request was issued. Unless the process is performed, another program cannot process the file, so the program must wait until the file is unlocked.

The conventional file access method is performed through the above processing. FIGS. 3 to 5 are flowcharts showing the flow of such processing. Figure 3 shows the process when a file is locked.
The ID (identification code) of the task (i.e. program) that issued the lock is set in the lock/task ID area [this process is shown as (14) in the figure]. (15)]. FIG. 4 is a flowchart showing the state of waiting for unlocking when writing to a file that is locked by another task.The waiting state of a task is realized by an event flag. When a file is locked, an event flag is assigned (this process is shown at (16) in FIG. 3), and that flag is reset. When a request for write processing comes from a task other than the task that has locked the file, it waits for the event flag assigned to the file to be set (this process is shown at (17) in FIG. 4).

FIG. 5 is a diagram showing the process when a file is unlocked, and the event flag is set (indicated by (15) in the figure) when the file is unlocked. As a result, the task that was attempting to update the target file is released from the wait state [indicated by (19) in FIG. 4].

[The problem that the invention attempts to solve]

Conventional file access methods have the problem that even access requests that require quick processing cannot be processed quickly due to file locking due to other processing.

The present invention has been made to solve the above-mentioned problems, and aims to provide a method that allows access requests to be processed quickly to be processed in advance.

[Means for resolving issues]

The file access method according to the present invention performs access control on an access basis instead of conventionally on a file-by-file basis, and also establishes a priority order so that accesses to processes that are desired to be executed quickly are processed preferentially.

[Effect]

In this invention, the lock function accepts locks in order of priority of processes, and when the lock by the current process is released (unlocked), the process with the highest priority among the processes issuing a lock request at that time Since requests for locks are received, tasks that need to be processed quickly can be processed with priority.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the file access method according to the present invention, in which (1) is a file, (2) is a process A, ! 31 is processing B, and +4) is a locking mechanism.

Note that processing A(2) requests permission to access file (1).
) and process B(3), process A(2) has a higher priority.

Next, the operation of this invention will be explained. FIG. 2 is a block diagram showing the operation of the present invention, in which the same reference numerals as in FIG. 1 indicate the same parts. permission,
(7) is an access request by process A (2), (81 is waiting for access request (7) to be processed, (9) is a lock release request by process B (3), and (10) is a new request by process B (31iC). access request, (11) l'i access request (
Permission % (12) for 7) is waiting for access request (1o) to be processed, and (13) is a lock release request by process A (2).

When an access request (5) is first received for file (1) by process B(3), there is no other access request for this file in locking mechanism (4), so process B(3)
) to issue permission (6). Next, when an access request (8) is received by process A(2) while process B(3) is accessing, the lock machine $11[4] knows that process B(3) is accessing and requests process A. Upon receiving the request (2), the process waits for processing B (3) to unlock (8). Processing B (3
) performs unlocking (9) and at the same time requests access (1).
0) Even if k is released, the lock mechanism (4) performs processing A (2)
Water retention has a higher priority, so issue access permission (11) to process A (2), and process B (3) wait until the process AUI is unlocked (13) (12).
It turns out. As described above, access to files is permitted according to the 11th priority of processing.

In the above embodiment, the explanation has been given for the case where there are two processes, but the same procedure can be performed even when there are two or more processes.

〔Effect of the invention〕

As explained above, the present invention has the effect that files can be accessed according to the priority order of processing, so that processing that must be performed quickly can be performed with priority.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the file access method according to the present invention, FIG. 2 is a block diagram showing the operation of the present invention, and FIGS. 3 to 5 are flowcharts showing the flow of processing according to the conventional method. It is. In the figure, (1) is the file, (2) is the process A, +31
is process B, [4) is the lock mechanism, 15) is an access request by process BK, (6) is access permission for process B,
(7) is an access request by process A, (8) is waiting for process A, (9) is a cancellation request by process B, (10) is an access request by process B, 1t) h is access permission for the processor, (12 ) is a wait for process B, and (13) is a release request by process A. Note that the same reference numerals in each figure indicate the same or corresponding parts. Masuo Oiwa, Figure 1, Figure 2, Figure 3, Procedure Amendment (Voluntary) To the Commissioner of the Japan Patent Office
nl, case display patent application Sho 60-1819
No. 88 2. Name of the invention File access method 3.
Representative of the person making the amendment: Moriya Shiki (4), Attorney (6), Contents of the amendment (1) The scope of claims in the specification will be corrected as shown in the attached sheet. (2) In the second line of page 2 of the specification, the phrase "File access method, sometimes" is corrected to "at the same time." 7. List of attached documents (1) Revised scope of patent claims
...... 1 copy C or more) Attachment 2, Claims (1) Files when there are file access requests from multiple processing programs for the same file in a computer that processes multiple programs at the same time A file access method characterized in that file access permission is granted only to 12 processing programs from among the plurality of processing programs that have requested the file access. (2) When there are file access requests from multiple processing programs, a step in which priorities are set for each file access request, and when a file that is the target of an access request is unlocked, file access is performed according to the above priority order. 2. The file access method according to claim 1, further comprising the step of granting permission.

Claims (2)

[Claims] (1) In a file access method when there are file access requests from multiple processing programs for the same file in a computer that processes multiple programs at the same time, one A file access method characterized by granting file access permission only to a processing program. (2) When there are file access requests from multiple processing programs, a step in which priorities are set for each file access request, and when a file that is the target of an access request is unlocked, file access is performed according to the above priority order. 2. The file access method according to claim 1, further comprising the step of granting permission.