Method for increasing free memory amount of main memory and computer therefore

1. A method for reducing boot time comprising the steps of:

starting, by use of a processor, a boot of a computer with an operating system capable of reading ahead a boot file into a cache area set in a free memory area of a main memory and changing a size of the cache area according to a size of the free memory area;

generating processes for loading the boot file into the main memory;

allocating working sets having a predetermined size to the generated processes by the operating system;

suspending a predetermined process selected out of the processes for loading the boot file;

swapping out a memory page of the suspended predetermined process to decrease a size of a working set for the process, wherein the decreased working set size is a minimum working set size set by default to each process by the operating system; and

increasing the size of the cache area according to the decreased working set size.

2. The method of claim 1 , further comprising the steps of:

reading ahead the boot file into the cache area whose size is increased; and

generating a process for loading the boot file stored in the cache area.

3. A method of expanding a free memory area comprising the steps of:

starting, by use of a processor, a boot of a computer comprising a storage device with a boot file stored thereon, a main memory, and an operating system;

generating processes for loading the boot file into the main memory;

allocating working sets having a predetermined size to the generated processes by the operating system;

suspending a predetermined process selected out of the processes for loading the boot file; and

swapping out a memory page of the suspended predetermined process to decrease a size of a working set for the process, wherein the decreased working set size is a minimum working set size set by default to each process by the operating system.

4. A computer comprising:

a processor;

a main memory;

a storage device, with a boot file stored therein, including an operating system;

a virtual memory;

a first means for selecting a predetermined process to be suspended, from all processes that load the boot file into the main memory; and

a second means for allocating working sets having a predetermined size to processes for loading the boot file, suspending the predetermined process selected by the first means, and swapping out a memory page of the suspended process to decrease a size of a working set for the process, wherein the decreased working set size is a minimum working set size set by default to each process by the operating system.

5. A program product comprising a non-transitory computer readable storage medium that stores code executable by a processor, the executable code comprising code to perform:

starting a boot of a computer provided with a storage device with a boot file stored thereon, a main memory, and an operating system;

generating processes for loading the boot file into the main memory;

allocating working sets having a predetermined size to the generated processes by the operating system;

suspending a predetermined process selected out of the processes for loading the boot file; and

swapping out a memory page of the suspended predetermined process to decrease a size of a working set for the process, wherein the decreased working set size is a minimum working set size set by default to each process by the operating system.

6. The program product of claim 5 , further comprising the step of increasing the size of a cache area used by the operating system according to the decreased working set size.

7. The program product of claim 5 , further comprising the step of swapping into main memory the memory page that has been swapped out before the suspended process resumes.

8. The program product of claim 7 , wherein the swapping-in step is performed after an elapse of a certain period of time after the process is suspended.

9. The program product of claim 7 , wherein the swapping-in step is performed when the boot is completed.

10. The program product of claim 7 , wherein, in the swapping-in step, the memory page of a suspended callee process is swapped in when a caller process is generated with reference to an interprocess communication list describing a relation between the caller process and the callee process.

11. The program product of claim 10 , wherein the swapping-in step includes the step of sending a window message to a process having a window handle.

12. The program product of claim 11 , wherein the swapping-in step is performed immediately after the process having the window handle is suspended.

13. The program product of claim 5 , wherein the predetermined process includes a process that is run on-demand in response to a user's operation.

14. The program product of claim 5 , wherein the predetermined process includes a process for loading a program that is not run at booting among all programs registered with a registry.

15. The computer of claim 4 , wherein:

the main memory includes a cache area; and

the second means expands the cache area according to the decrease in the working set size.

16. The computer of claim 15 , wherein the first means requests the second means to resume the suspended process.

17. The computer of claim 16 , wherein the first means swaps in the memory page swapped out through the second means before a page fault occurs on an access from the processor.

18. The computer of claim 17 , wherein the first means requests the second means to swap in the swapped-out memory page into the main memory before the suspended process resumes.

19. The computer of claim 17 , wherein the first means requests the second means to send a window message to a process having a window handle.