JPH02270032A - Loading system - Google Patents

Abstract

PURPOSE:To carry out the larger number of user tasks at one time by securing a secondary storage when the task executing level is lower than a fixed value and loading a general program into the secondary storage. CONSTITUTION:If the task executing level obtained by a task executing level deciding means 2 has the priority lower than a fixed level, the means 2 calls out a secondary storage securing means 5 without assigning a real memory to a logical space secured previously. The means 5 secures the secondary storages equal to the number of logical spaces secured previously and then calls out a secondary loading means 6 after assignment of the logical spaces. The means 6 loads a general program into the secured secondary storage in a state equal to that secured with push of an on-demand paging ODP mechanism. Thus the larger number of user tasks are carried out at one time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a loading method in O8, and in particular, for tasks whose execution level is lower than a certain value when loading a general program, the program is stored in real memory. By loading onto secondary storage instead of into
This paper relates to a loading method that can effectively utilize limited real memory.

[Conventional technology]

Conventionally, in this type of loading method, a logical space and a real memory are secured in advance, regardless of the execution level of a task, and a general program is loaded onto the real memory.

[Problem to be solved by the invention]

In the conventional loading method described above, the logical space and real memory are secured in advance, regardless of the execution level of the task, and the general program is loaded onto that real memory. However, there is always a problem that real memory is reserved for loading general programs, and the limited real memory is wasted.

[Means to solve the problem]

The configuration of the loading method of the present invention is based on an operating system that supports virtual memory having an on-demand paging (hereinafter referred to as ODP) mechanism.
In the loading method of a general program in System + hereinafter referred to as O8, a task execution level determination means for determining the level of a task execution level that determines the priority order when a task is executed, and the general program a logical space securing means for securing a logical space for loading the task; a real memory securing means for allocating real memory to a previously secured logical space when the task execution level is higher than a certain value; real memory loading means for loading the general program onto real memory; secondary storage securing means for allocating secondary storage to a previously reserved logical space when the task execution level is lower than the certain value; and securing the same. The ODP mechanism transfers a page frame, which is an area into which the real memory is divided into a size corresponding to the size of the page in order to store pages, to the secondary storage and makes the page frame free. and a secondary storage loading means for loading the general program in the same state as when the PUSH operation is performed.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a diagram showing the overall configuration of an embodiment of the present invention. In the figure, 1 is a logical space securing means, 2 is a task execution level determining means, 3 is a real memory securing means, 4 is a real memory loading means, 5 is a secondary memory securing means, and 6 is a secondary memory loading means. be.

When loading a general program, the logical space securing means 1 first secures a logical space of a size necessary for loading the general program.

Next, the task execution level determining means 2 determines the execution level of the task on which the general program is executed.

If the obtained execution level is a level with a higher priority than the fixed value, the task execution level determination means 2:
The real memory securing means 3 is called to allocate real memory to the logical space secured in advance. Further, the real memory loading means 4 is called from the real memory securing means 3 and loads the general program onto the allocated real memory.

If the execution level determined by the task execution level determination means 2 is a level with a lower priority than a certain value,
The task execution level determining means 2 calls the secondary storage securing means 5 without allocating real memory to the logical space secured in advance. The secondary storage securing means 5 secures the same amount of secondary storage as the logical space secured in advance and allocates it to the logical space, and then calls the secondary storage loading means 6. The secondary storage loading means 6 loads the general program onto the secured secondary storage in the same state as when it is PUSHed by the ODP mechanism.

Next, a case will be shown in which a general program loaded onto the secondary storage is executed.

General programs loaded onto secondary storage are
Since the state is the same as when PUSH is performed by the DP mechanism, a page fault (state B where real memory is not allocated to the logical space) interrupt occurs when reading an instruction.

The ODP mechanism uses this interrupt as a trigger to allocate real memory to the page where the page fault interrupt has just occurred, reads the program corresponding to that page from secondary storage, and re-executes the instruction that caused the page fault interrupt.

In this way, programs are executed sequentially while allocating real memory only to necessary pages.

〔Effect of the invention〕

As explained above, in the loading method in O8, if the execution level of a task is lower than a certain value, the present invention secures secondary storage without allocating real memory, and stores data on the secondary storage. By loading general programs, limited real memory can be used effectively, and the real memory used by one task can be reduced, so more user tasks can be run at the same time. .

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Logical space securing means, 2... Task execution level determining means, 3... Real memory securing means, 4... Real memory loading means, 5... Secondary memory securing means, 6.
...Secondary memory loading means.

Claims (1)

[Claims] On-demand paging (OnDemandPagi)
ng (hereinafter referred to as ODP) mechanism that supports virtual memory.
In the loading method of a general program in a system (hereinafter referred to as OS), a task execution level determination means for determining the high or low task execution level that determines the priority order when a task is executed; A logical space securing means for securing a logical space for loading, a real memory securing means for allocating real memory to a previously secured logical space when the task execution level is higher than a certain value, and a real memory securing means for securing a logical space for loading the task; real memory loading means for loading the general program onto memory; secondary memory securing means for allocating secondary memory to a previously reserved logical space when the task execution level is lower than the certain value; On the secondary storage, the ODP mechanism moves the page frame, which is an area into which the real memory is divided into a size corresponding to the page size in order to store pages, to the secondary storage and makes the page frame free. A loading method comprising: a secondary storage loading means for loading the general program in the same state as when a PUSH operation is performed.