JPS6353656A - Storage area control method for secondary storage part - Google Patents

Abstract

PURPOSE:To efficiently use the storage area of a secondary storage part by allocating continuous areas according to a file list when a new file is generated and updating the contents on the file list if unnecessary files show up. CONSTITUTION:When a garbage collection request enters an I/O control part 11, it is transmitted to a control part 15. The file list of a primary storage part 14 is sequentially referred. A film number whose state identifier is idle is deleted, and a collation list is generated in order to advance subsequent file numbers by as much as the deletion. Next, the file list is again referred to from top to bottom in sequence. A file is read, and the start address and size of the file concerned are set. If the file has statement regarding the file numbers, they are again numbered according to the collation table which has been generated. The read-out file is rewritten at a new start address that is advanced by an area to be collected as garbage. Similarly files from next to final are rewritten.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for managing the storage area required for large-capacity files on a secondary storage unit in a multiprocessor system.

BACKGROUND OF THE INVENTION One method of allocating an area required for a file on a secondary storage unit is to allocate all the necessary area at once as a continuous area when creating a file. Direct access to a file in a contiguous area allocated in this manner minimizes the movement of the head used for the secondary storage medium, making it possible to access the file at high speed.

Problems to be Solved by the Invention However, in the above method, if the file sizes are uneven, the unused area becomes fragmented due to the allocation of continuous areas. Therefore, there is a problem in that a method for collecting these fragmented unused areas (hereinafter referred to as garbage collection) is required.

The present invention solves these problems by making it possible to easily perform garbage collection, and also to easily allocate and release file areas, thereby reducing the storage area of the secondary storage unit. The purpose of this invention is to provide a storage area management method that allows efficient use of storage areas.

Means for Solving the Problems In order to solve the above problems, the present invention provides a file list as a file storage area management table, and when a new file is created, this file list is used as the basis for creating a new file. It allocates a continuous area to the file list, and updates the contents of this file list when a file is no longer needed.

Operation With the above configuration, when creating a file, necessary continuous areas are allocated by assigning each unique file number, and the corresponding portion of the file list 1- is read out using this file number.

When a file is deleted, the used contiguous space is freed and garbage collection can be easily performed when necessary.

EXAMPLE An example of the present invention will be described below based on the drawings. 1st
The figure shows a schematic block diagram of a storage area management device for a secondary storage unit in an embodiment of the present invention.

In this example, in a multiprocessor system,
It has functions such as allocating and releasing file areas, reading and writing files, and performing garbage collection on storage areas of secondary storage devices in response to requests from other processors. 11 is an input/output control unit from other processors in a multiprocessor system;
2 is a control device for a secondary storage unit such as a hard disk, 13
is the secondary storage section. The storage area in this secondary storage device 3 is the object of management by the storage area management device shown in this embodiment, and a file list is provided as a file management table. 14 is a primary storage unit such as a semiconductor memory, and the file list is loaded from the secondary storage unit 13 to the primary storage unit 14 when the device starts operating. Reference numeral 15 is a control unit for combining the present device.

As shown in Figure 2, the areas managed by this file list are arranged in order from the smallest address to the entire storage area of the secondary storage unit 13. The number management area will never come before the smaller file number management area,
The storage areas are mapped one-to-one on the file list without changing the order.

Next, the structure of the file list developed in the secondary storage unit 13 will be explained using FIG. 3. Here, the file number is not written in the file list. The file number is used as an index value when referring to the file list.

In FIG. 3, 3] describes the status identifier of the area indicated by the corresponding file number in the file list, and the contents of this identifier indicate whether or not the corresponding area is in use. If the area is not in use, that file number is not used for a file, and this file number will be given to the next file allocated to this area. 32 describes the starting address of the corresponding area. 33, if the corresponding area is used for a file, the size of the area used for the file is described. 34 describes the size of the corresponding area itself. In other words, when attempting to allocate a file to this area, it indicates the maximum file size that can be allocated. Therefore, the size of this area is usually equal to the size of the file originally allocated to this area, and the size of the currently allocated file is compared to this area.
or equal. In other words, the area obtained by subtracting the current file size from the size of the relevant area is the area to be garbage collected.

Next, the operation of the above embodiment will be explained. Here, in order to describe the effectiveness of the file list, we will first describe a file area allocation method, then an area deletion method, and finally a garbage collection method. FIG. 4 shows the procedure for allocating a file area. Input/output control section 11
A request for allocating a file area is input to the controller 15, and this request is sent to the control unit 15. The control unit 5 sequentially refers to the file list l- in the primary storage unit 14. At this time, it searches for an area whose status identifier indicates a free status and whose size is greater than or equal to the requested file size, and returns the value of the corresponding file number to the input/output control unit 11. .

Next, the procedure for releasing the file area is shown in FIG. When a release request is received by the input/output control section 11, this request is sent to the control section 15. The control unit 15 refers to the file list in the next storage unit 14 using the notified file number. At this time, change the status identifier from in use to free,
Set the file size to O. The process is now complete, and a completion notification is returned to the input/output control unit II.

Finally, the garbage collection procedure is shown in FIG. A request for garbage collection enters the input/output control section 11, and this request is sent to the control section 15. The control unit 15 sequentially refers to the file list in the primary storage unit 14, deletes file numbers whose status identifiers are empty, and creates a comparison table for moving subsequent file numbers forward by that amount. Next, refer to the file list again in order from the top, read the file, change the starting address of the file and the size of the file from cell number 1, and if there is a description of the file number in the file,
Change the file numbers based on the comparison table created earlier. After that, the read file is rewritten from the new starting address, which is filled in by the area subject to garbage collection.

Garbage collection processing is completed by performing this in order until the last file.

Effects of the Invention According to the present invention, by using a file list,
Garbage collection can be easily performed, and this file list can be effectively used when allocating and releasing storage areas on the secondary storage unit, thereby making it possible to use the storage area of the secondary storage unit efficiently. Can be done.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a storage area management device of a secondary storage unit in an embodiment of the present invention, FIG. 2 is a diagram showing a mapping relationship between a file list and all storage areas of the secondary storage unit, and FIG.
Figure 4 is a flowchart showing the configuration of a file list, Figure 4 is a flowchart showing the procedure for allocating the storage area used for files, Figure 5 is a flowchart showing the procedure for releasing the storage area, and Figure 6 is a flowchart showing the procedure for garbage collection. It is a diagram. 11... Input/output control unit, 12... Secondary storage control unit,
13...Secondary storage section, 14...-secondary storage section, 15.
...Control unit for all devices. Agent Yoshihiro Morimoto 2nd ward Futadako? 37 3zJj Jll Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. A storage area management method for a secondary storage unit that uses a file list provided as a storage area management table on the secondary storage unit to manage the entire area required for a file as a continuous storage area.