JP2003330741A - Information processing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that at the time of execution, the storage area becomes insufficient in an information processor having only a little hardware resource and an interpreter-system execution environment. <P>SOLUTION: This information processor having interpreter-system execution environment is characterized in that, at the time of performing a program execution control system and means, allocation and deallocation of storage area are performed dynamically. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of managing a device control program on an information processing device having a small storage area.

[0002]

2. Description of the Related Art In the current computer environment, an operating system equipped with a virtual storage system using abundant physical memory and an external storage device such as a hard disk can be used, and it is possible to operate on the same computer at the same time as before. The number of programs has improved dramatically. On the other hand, from the viewpoint of software productivity, an environment such as JAVA (registered trademark) that allows the same program to be executed on different types of computers has become widespread. In JAVA (registered trademark), it is ideal that a program can be created once and then run on any computer having a JAVA (registered trademark) execution environment.

In order to operate the same program in such different program execution environments, a system in which a virtual machine as shown in FIG. 1 is introduced can be considered.

In recent years, computers called network computers (hereinafter abbreviated as NC) to which this mechanism is applied are becoming widespread.

The NC is a new type of computer in which required applications and execution environments are minimized by narrowing down users' uses such as offices and homes. The feature is that all the included programs are acquired through a server connected on the network (FIG. 8). For this reason, this system is particularly effective in the case of regular work such as offices and a large number of required units.

[0006]

The fact that the same program can be executed in different environments means that the same program is executed in an environment having abundant hardware resources and an environment having few resources. . Since NC does not have its own hard disk, swap,
Virtual memory such as paging is not realized, and the program is executed only in real memory.

For this reason, problems such as storage capacity, which are less likely to occur in personal computers having abundant hardware resources, are exposed.

In such an environment, there is a high possibility that a program created without paying attention to the memory capacity on abundant resources will not operate.

Further, this problem is particularly remarkable in a system having no virtual memory such as swapping or paging.

The present invention has been made in view of the above problems, and provides a module unloading function on the program execution environment.

Further, considering the priority when unloading,
We also propose a method of unloading from less important modules.

[0012]

In order to achieve the above object, the present invention has the following constitution.

It has an execution environment of an interpreter format.

The execution environment has an accessible external storage device such as a hard disk or a hard disk connected to a server on the network.

The execution environment has means for loading a program and modules required for the program from an external storage device.

The execution environment has means for monitoring access to the module.

The execution environment has means for dynamically loading the modules required for program execution.

The execution environment has means for unloading unnecessary or unneeded modules during program execution.

The execution environment has means for calculating the necessity degree of the module.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) Embodiment 1 is constructed as follows. First Embodiment FIG. 1 is a diagram showing a configuration of a first embodiment of the present invention. Reference numeral 1 is a central processing unit (CPU) that controls various processes
Is a hard disk (HD) that stores the program of the present invention, and 3 is a random access memory (RAM) that can be executed by the CPU.

Further, the execution environment of the computer is as shown in FIG.

The program execution environment is as shown in FIG. 301 is the hardware shown in FIG.
Is an operating system that controls the hardware, 303 is an interpreter program execution environment that operates on the operating system, 304 is a program that is executed on the interpreter, and 305 is an access to each module used in the program. Is a means to do.

At the start of execution of a program, it is assumed that only the system library attached to the interpreter and the main part (Main) of the program to be executed are loaded. The system library itself is also unloaded
It is assumed that it is divided into modules and classes so that it can support.

When a variable or function (method) in another module is accessed in the process of executing the Main module, control is transferred to the monitoring module 305 and whether the module can be loaded according to the module loading procedure of FIG. (401). Transferring control to such a monitoring module can be easily realized in an interpreter type execution system.

In checking the module size of 401, if a sufficient amount of memory is available, the load will proceed normally. When a sufficient amount of memory is not secured, the necessity of each module is checked based on the module table of FIG. Here, the number of times the module is accessed is taken as the degree of necessity. That is, it is the total number of times of access to variables and functions for each module since the execution of the Main module.

With reference to this table, although the module is first found among the modules with the lowest necessity, the code area is unloaded. In general, the data area cannot be released unless it is possible to use garbage collection or the like because it is not known whether or not there is a reference from another.

After the release, in order to record that it has been unloaded, it is registered in the Unload table as shown in FIG. This table is used for reloading in the procedure of FIG. 7 when the next function call to the unloaded module occurs.

The above procedure is repeated until the required memory amount is secured.

At this time, if Unloading is performed a predetermined number of times, a run-time error is generated and the process ends, in order to avoid an infinite loop.

In this way, the necessary module can be loaded while releasing the code area of the module that is rarely used.

(Other Embodiments) (Second Embodiment) In the second embodiment, JAVA (registered trademark) or S
Assume an object-oriented language such as mallTalk. In these languages, since there is no pointer like C language, it is possible to check whether or not there is a reference to an object at any time. The presence or absence of this reference is determined in Example 1.
By using instead of the access count of, class unloading can be realized depending on whether or not there is a reference.

(Third Embodiment) In the third embodiment, an NC connected on the network and a server for managing the NC are assumed. An NC that does not have a hard disk locally has a class file on the server. When reloading the unloaded class file, the server is requested to load the class.

[0033]

The present invention has proposed means for making a storage area effective on a system having no virtual memory. A feature of the present invention is that by recording the modules that have been unloaded, it is possible to ensure the security for the next access. Further, in order to ensure security, it is important that the code area is positively opened and the data area is not opened unless the safety is decided.

According to the present invention, it can be expected that even a system having a small storage area can effectively utilize the storage area.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an NC.

FIG. 2 is a block diagram of an interpreter system.

FIG. 3 is a block diagram of an interpreter system including a module monitoring mechanism.

[Fig. 4] Module using a module monitoring mechanism
Loading procedure.

FIG. 5 is an access table of modules possessed by the module monitoring mechanism.

FIG. 6 is a table that records modules that have been unloaded.

FIG. 7 is a procedure of module loading considering an unloaded module.

FIG. 8 is a network including an NC and a server.

[Explanation of symbols]

1 Central processing unit (CPU) 2 External storage device (hard disk, HD) 3 Random access memory (RAM) 4 Network interface card (NIC) 5 Network computer (NC)

Claims (5)

[Claims] 1. Information comprising an interpreter type execution system having means for unloading a part of a program at execution time, means for releasing a storage area, and means for reusing the released storage area. Processing equipment. 2. The information processing apparatus according to claim 1, further comprising means for determining a less frequently used module in a program, and means for reloading an unloaded module. 3. The information processing apparatus according to claim 2, wherein the usage frequency is the number of times a function or variable in the module is referenced. 4. The information processing apparatus according to claim 3, wherein the module is a device driver. 5. The information processing apparatus according to claim 2, wherein the usage frequency is whether or not there is a reference to an object in the module.