JPH01185729A - Overlay structure program execution system - Google Patents

Abstract

PURPOSE:To prevent a program from being infeasible by deciding whether or not a file control block to be used prior to the execution of an overlay structure program is loaded on a main storage and starting the execution after the file control block is loaded when it is not loaded. CONSTITUTION:Prior to the execution of the overlay structure program, it is decided by a file control block load decision means 4 whether or not the file control block FCB used in the overlay structure program is loaded on the main storage. And when it is not loaded, the execution of the overlay structure program is started after the file control block FCB is loaded on the main storage by a file control block loading means 5. In such a way, it is possible to prevent the program from being infeasible.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for executing an overlay structure program in a combiator system, and particularly relates to a method for executing a load module of an overlay structure program already created on an external storage device. .

[Conventional technology]

Execution methods for overlay structured programs can be roughly divided into two: methods in which compiling, linking, and execution are performed as one job (or activity), and methods in which linking and execution are performed as separate zips, i.e., programs that have already been created on an external storage device. There is a method of executing a load module of an overlay structure program. In the former method, various control information for files required when executing a program, such as file name and file status.

The file control block containing buffer information, etc. has already been loaded into the main memory in the previous processing before starting the execution of the overlay structure program, and there is no need to load it into the main memory again after execution. In the latter method, the file control block has not yet been loaded into main memory at the start of execution, so conventionally, the file control block was loaded in the main routine (so-called root part) of the overlay structure program, which is the user program. The user sets the process to perform this, and the user program itself controls the loading of the file control block onto main memory.

[Problem that the invention seeks to solve]

Therefore, if the user forgets to set such processing in the main routine, the overlay structure program cannot be executed because the file control block is not loaded onto the main memory. As described above, the former method does not require such settings, and the program creation method differs depending on the execution method, so forgetting the settings as described above is likely to occur.

An object of the present invention is to prevent overlay structure programs from becoming unexecutable due to the causes described above.

[Means for solving problems]

To achieve the above object, the present invention provides an execution method for an overlay structure program that has already been created as a load module on an external storage device, in which a file control block used by the overlay structure program during execution is loaded onto the main memory. A file 111i block load determining means is provided for determining whether the file 111i block is loaded, and a file control block loading means is for loading the file control block onto the main memory. When the determination means makes a determination and it is determined that the file control block has not been loaded onto the main memory, the file control block loading means loads the file control block onto the main memory and then loads the file control block onto the main memory. I am trying to start executing a structural program.

[Effect]

Prior to execution of an overlay structure program, a file control block load determination means determines whether or not a file control block used by the overlay structure program has been loaded on the main memory, and if it has not been loaded, the file control block After the file control block is loaded onto the main memory by the loading means, execution of the overlay structure program is started.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram showing an example of a computer system to which the present invention is applied. The computer system of this embodiment has an overlay structure program load module L.
It is comprised of an external storage device 1 in which M and a file control block PCB are stored, and a computer 2 that executes an overlay structure program using a real storage method.

The computer 2 includes a preprocessing section 3 and an execution section 6. This preprocessing unit 3 is a part that is conventionally always executed prior to the execution of a program, and for example, it clears the main storage area used by the program. A file control block load determining means 4 and a file control block loading means 5 are provided.

The file control block load determining means 4 is means for determining whether the file control block PCB used when executing the load module LM of the overlay structure program stored on the external storage device 1 has been loaded on the main memory. If it is determined that the file control block PCB is loaded onto the main memory, the execution unit 6 is instructed to execute the load module LM, and if it is determined that the file control block PCB is not loaded, the file control block loading means 5 is activated. do. Generally, the load module LM includes an area in which information indicating where on the external storage device 1 the file control block PCB is stored is stored;
Since there is an area in the main memory that holds information indicating which part should be loaded, the file control block load determination means 4 reads the contents in the main memory according to the load destination information held in the latter area. According to this read information, it is possible to determine whether the file control block PCB is loaded or not.

Further, when the file control block load determining means 4 determines that the file control block PCB has not been loaded, the file control block loading means 5 stores the file M? It is a means for loading the II block PCB, and then the load module LM is sent to the execution unit 6.
instruct the execution of

Next, the operation of this embodiment configured as described above will be explained.

The computer 2 executes the processing of the preprocessing section 3 before executing the load module LM of the overlay structure program stored in the external storage device l.

In the preprocessing unit 3, first, the file control block load determining means 4 determines whether the file control block PCB used by the load module LM during execution has been loaded on the main memory.

- If the load module LM has been loaded, it instructs the execution unit 6 to execute the load module LM. In response, the execution unit 6 loads the execution portion of the load module LM of the overlay structure program from the external storage device 1 onto the main memory and starts execution.

On the other hand, when determining that the file control block PCB has not been loaded onto the main memory, the file control block load determining means 4 loads the file control block loading means 5.
Start. In response, the file control block loading means 5 loads the file control block PCB from the external storage device 1fl onto the main memory, and issues an execution instruction to the execution unit 6 after the loading is completed. The execution portion of the load module LM of the overlay structure program is loaded from the storage device 1 onto the main memory and execution is started.

〔Effect of the invention〕

As explained above, according to the present invention, prior to execution of an overlay structure program, it is determined whether or not a file control block used by the overlay structure program has been loaded on the main memory, and if the file control block is not loaded. When it is determined that the overlay structure program is loaded, the execution of the overlay structure program starts after it has been loaded. Even when executing as a separate job, the user does not need to set up processing to load file control blocks in the overlay structure program. Therefore, there is no possibility that the file control block will not be loaded due to a user error and the overlay structure program will not be able to be executed.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an example of a computer system to which the present invention is applied. In the figure, 1...external storage device 2...computer 3...
Preprocessing unit 4...File control block load determination means 5...
File control block loading means 6...Execution unit LM...Load module for overlay structure program PCB...File control block

Claims (1)

[Claims] In an execution method for an overlay structure program that has already been created as a load module on an external storage device, whether or not a file control block used by the overlay structure program during execution is loaded on the main memory. A file control block load determining means for determining a file control block load, and a file control block loading means for loading a file control block onto main memory are provided, and the determination by the file control block load determining means is performed prior to execution of the overlay structure program. and when it is determined that the file control block is not loaded onto the main memory, the file control block loading means loads the file control block onto the main memory and then executes the overlay structure program. An overlay structure program execution method characterized in that an overlay structure program is started.