JPH0795297B2 - File access controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention provides a file including a page buffer and a control table indicating a state of updating and referencing the page data between an information processing unit and a file storing page data of a virtual sheet. In the access system, when the content of the control table is only the page data that needs to be updated, the processing information of the second control table is used to save a plurality of continuous page data sufficiently far from the current processing position in the file. By performing such control, the data exchange of the page buffer is speeded up and the number of file accesses is reduced.

[Industrial application field]

The present invention relates to an improvement of a file access control device for storing page data of virtual paper.

[Conventional technology]

Conventionally, under the control of an information processing unit, a file storing page data of a virtual sheet, which will be described later, for example, a page buffer is provided between the file and an external storage device, and page data is updated and referred to due to input / output on both sides thereof. A control table is provided to indicate the state of. The file has a plurality of sides of virtual paper, and each side is divided into N pages of a physical unit of about 2 KB and stored, and the one or a plurality of pages transfers between the page buffer and the file.

FIGS. 3A and 3B show an example of a conventional file access system of this type.

In the figure, a read (reference) or write (update) request from the information processing unit 1 to the addresses of the virtual paper number and the page number within the paper in the file 4 is requested by the control buffer 2.
To the page buffer 3 via. According to this request,
The necessary address in the file 4 is accessed and loaded into the page buffer 3, and conversely, the page data to be updated written in the page buffer 3 is saved in the corresponding address of the file 4. The control buffer 2 and the page buffer 3 temporarily hold the number of page data required for processing the file 4. The control buffer 2 is shown in FIG.
The control buffer 12 _n for each page is shown in FIG. 3, and the last two bits represent the reference bit and the update bit in addition to the read and write addresses corresponding to the requested page data. In the reference bit, "0" is not used, "1" is being referred to, and in the update bit, "0" means no writing and "1" means writing. The page data corresponding to these addresses are temporarily held in the page buffer 3 as illustrated in the figure.

FIG. 4 is a flow chart showing the operation in the configuration of FIG. In the figure, i) When the page data is on the page buffer 3, it is not necessary to save to or load from the file 4, the control table is not changed for read, and the update bit is set for write. Change it to 1 "and finish the process,
Move to next page data.

ii) If the page data is not on the page buffer 3 and there is an update bit "0", it becomes a candidate position for loading a new page from the file 4. The following procedure is the same as i).

FIG. 5 (a) shows an example of this case, where the mark * indicates the position of the new page load candidate.

iii) When the page data is not on the page buffer 3 and there is no update bit "0", the file 4 is saved and the area on the page buffer 3 is emptied before loading.

FIG. 5 (b) shows an example of this case. If the process proceeds from the state of FIG. 5 (a), only the update bit "0" will be the target of loading, and the update bit "0" will be written. 1 "increases, so at the end all update bits are" 1 "
It becomes the state of.

[Problems to be solved by the invention]

If the state illustrated in FIG. 5 (b) described in iii) of the above-mentioned conventional example is reached, the conventional control table update bit and reference bit save / load control will be a chore. In subsequent operations, a random save method is generally used, but this cannot reduce the number of access to the file. As described above, when the contents of the control table are only the page data that needs to be updated, it is considered that the page data in the page buffer 3 is replaced at high speed and the number of accesses to the file 4 is reduced.

Therefore, the characteristics of the processing mode are as follows.

The next processed page has a high frequency before and after the page currently being processed (reference bit “1”).

When one operation covers a plurality of pages, those pages have continuity and processing direction. Therefore, it is efficient to save / load multiple pages at once.

By using these characteristics, when the state shown in FIG. 5 (b) is reached, it should be possible to save / load a plurality of continuous page data at a position sufficiently distant from the current processing position all together. is there.

An object of the present invention is to provide a file access control device which speeds up the replacement of page data in a page buffer and reduces the number of access to the file when the content of the control table is only the page data that needs to be updated. To provide.

[Means for solving problems]

In order to achieve the above object, in the present invention, a page buffer for temporarily holding page data in a file, a control table for storing information indicating update / reference status of page data in the page buffer, and the page buffer A second control table that stores information indicating an address relationship of each page data in another page data with another page data, and the data in the page buffer are referenced one by one, and the contents of the control table are updated. When only the required page data is obtained, information processing for selecting the page data at the address position farthest from the page data currently being referenced from the second control table and saving the selected page data in the file Section, and is further separated from the page data currently being referred to above. It is characterized in that there are a plurality of continuous page data at the specified address position.

[Action]

With the above configuration, all the conventional control tables need to be updated, and in the case of a dead end, it is possible to effectively overcome this problem. For example, the page data position for the current process (reference bit “1”) is handled for each page data. Then, the address in the second control table is searched, the one with the most spaced address is selected, a plurality of page data continuous with the page data at this position is taken out, and these are sent to the file to save.

As a result, the update bit of these old areas changes to "0" and new page data can be received.

〔Example〕

1 (a) and 1 (b) are configuration explanatory views of an embodiment of the present invention.

In this figure, the difference from the conventional example of FIGS. 3 (a) and 3 (b) is the content of the control buffer 11 shown in FIG. 3 (b).

That is, in addition to the control table 12 _n showing the same update bit and reference bit as in FIG. 3, the second control table 13 _n which is the main part of the present invention is included. As shown in FIG. 7B, the control table 13 _n prepares an area of, for example, 1 word and 16 bits, writes the paper number when the file 4 includes a plurality of virtual papers in the first 4 bits, and The page number in the paper shall be written in 12 bits.

In the same control table 12 _n as in the conventional example, when all the update bits are “1” as shown in FIG. 5 (b) for each page data, the second control table 13 _n is set for each page. The data is searched. Then, the data at the most distant address is extracted from the position of the page data currently being processed (reference bit “1”), and a plurality of page data continuous with this page data are collectively saved in the file 4.
Note that when the page data is loaded from the file 4 to the page buffer 3, it can be controlled using the second control table 13 _n . That is, in this case, with respect to the current processed page data position, the continuous plural page data located at the position toward the next processed page data is described in the control table 13 _n of the corresponding page data, and the loading is performed according to this Be done.

FIG. 2 is an explanatory diagram showing an operation example of the embodiment of the present invention.

In the figure, when the control buffer 11 is in the state shown in FIG. 5 (a), it is assumed that page m from the file 4 is currently being referred to. Then, as an example of processing, consider a case where a vector (line) is drawn downward from the m page in a bit map figure.

The procedure is as follows.

Processing is started on page m on page buffer 3 and a straight line is drawn.

Since page m + 1 is on page buffer 3,
Move to page m + 1 and continue straight line drawing.

Loading is necessary because there are no m + 2 pages on page buffer 3.

Since all the control tables 12 _n need to be updated,
It is necessary to save to the file 4, and the i−1, i, i + 1 pages located farthest from the current processing position m page are collectively saved according to the contents of the second control table 13 _n . In this case, access is required only once.

Since it is the downward processing, there is a possibility that pages of m + 3 or less may also be required. Therefore, according to the contents of the second control table 13 _n , m + 2, m + 3, m + 4 pages are collectively included in the file 4.
To page buffer 3 from. In this case, access is required only once.

 Continue drawing straight lines for m + 2 pages or less.

〔The invention's effect〕

As described above, according to the present invention, when the content of the conventional control table is only the page data that needs to be updated, the processing information of the second control table is used and a plurality of data items sufficiently separated from the current processing position are used. It controls to save continuous page data to a file. As a result, multiple continuous page data at a position far from the current processing position are saved to the file all at once.Therefore, the data exchange at the page buffer is speeded up without affecting the current processing position, and the number of file access is significantly increased. It can be reduced to.

[Brief description of drawings]

FIG. 1 is an explanatory view of the configuration of an embodiment of the present invention, FIG. 2 is an explanatory view showing an operation example of the embodiment, FIG.
FIG. 5 is an operation explanatory diagram of the conventional example, and FIG. 4 is a flow chart showing the operation of the conventional example. In the figure, 1 is an information processing unit, 3 is a page buffer, 4 is a file, 11 is a control buffer, and 12 _n is a control buffer. A control table, 13 _n is a second control table.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Stuart E. Madnick, John J. et al. Donovan, Katsuo Ikeda "Computer Science Research Book Series Operating System" 5th edition (1983-6-15) P.P. 166-188 "3.6.2 Software", especially 3.6.2.9, P. 624-625 "9.4.3.2 Page replacement algorithm", especially post page

Claims (2)

[Claims] 1. A page buffer for temporarily holding page data in a file, a control table for storing information indicating update / reference status of the page data in the page buffer, and individual page data in the page buffer. , A second control table that stores information indicating an address relationship with other page data, and the data in the page buffer are referenced one by one, and the content of the control table is only the page data that needs to be updated. In this case, it has an information processing unit that selects page data at an address position farthest from the page data currently being referenced from the second control table and saves the selected page data in the file. File access control device. 2. When the data in the page buffer is referred to one by one and the content of the control table is only the page data that needs to be updated, it is at the address position farthest from the page data currently being referred to. The file access control device according to claim (1), further comprising an information processing unit that saves a plurality of continuous page data in a file.