JPH0535844A - Electronic filing device - Google Patents

Abstract

PURPOSE:To facilitate the management of a look-ahead memory by managing a prescribed amount of pages for each terminal based on the weighting of each page and managing the pages exceeding the prescribed amount commonly to each terminal. CONSTITUTION:As the management means of the memory looking ahead from the electronic file, a management table managing a prescribed amount of pages based on the weighting of each page and an excessive management table managing the pages exceeding the prescribed pages commonly to each terminal are provided. A workstation A looks ahead at five pages of A1 to A5, a workstation B looks ahead at two pages of B1 and B2, and a workstation C looks ahead at two pages of C1 and C2. The respective page management tables manages up to fifteenth page, and the sixteenth page and subsequent are managed by the excessive management table provided commonly to the respective workstations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic file device having a read-ahead memory.

[0002]

2. Description of the Related Art An electronic file device having a plurality of decks, mounted with a large-capacity storage medium such as an optical disk, and processing access requests from a plurality of terminals is used. The electronic file device includes a memory, and temporarily stores the data read from the optical disc, and then transfers the data to the requesting terminal.

This memory stores data in which read-requested pages from each terminal are preread, and the area of this memory is managed by a management table weighted page by page for each terminal. If all memory areas have been read and there is a further read request, the read-ahead page in any area will be deleted and used. In this case, the page read for each terminal from the management table. , And delete pages with lower weight than the weight of the page to be used.

[0004]

In such a memory management method, as the number of blocks (pages) managed increases, the size of the management table also increases. Therefore, when deciding a block to be deleted, it takes a long processing time to decide a block with a low weighting, and an unnecessary block is also managed.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic file device which facilitates management of a prefetch memory.

[0006]

In order to achieve the above object, a memory for storing pages read ahead of an electronic file and data stored in the memory for each terminal accessing the electronic file are stored in each terminal. And a page management table that manages a predetermined amount of pages for each terminal based on the weighting of each page, and a page management table that manages pages exceeding this predetermined amount in common for each terminal. It is managed by the surplus management table.

[0007]

Since the number of pages in the page management table for managing the prefetched page for each terminal is limited to a predetermined number, the management becomes easy, and it becomes easy to search for a page having a lower weight than the page to be read. Also, pages exceeding this predetermined number are registered in the surplus management table, and when determining the pages to be deleted, it is necessary to search for pages with a low weighting by deleting the pages described in this surplus table. Nor. When the pages described in this surplus table are insufficient, it is sufficient to search for a page with a lower weight than the page management table, so the management speed is improved.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a relationship among a memory, a page management table, and a surplus management table. FIG. 2 is a diagram showing a configuration diagram of the electronic file device of this embodiment. First, FIG. 2 will be described in order to grasp the whole. Reference numeral 1 denotes a workstation as a terminal. The workstation 1 is described as three, but a plurality of workstations may be used. A file controller 2 constitutes an interface with each workstation 1. A multi-deck control unit 3 inputs a command from the file controller 2, controls a multi-deck unit 4 described later based on the command, and transmits the result to the workstation 1 via the file controller 2. The multi-deck control section 3 is composed of a first control section 31 including a disc exchange control section and a command control section, and a second control section 32 for controlling the deck section according to a command from the command control section. 4 is a multi-deck section (for example, 24 or 48
The optical disk 5 comprises a plurality of optical disks 5, a transport mechanism section 6 for moving the specified optical disk 5 from the plurality of optical disks 5 to a specified deck section 7, and two deck sections 7. A memory 8 pre-reads data from the multi-deck unit 4 and stores it. A memory control unit 9 manages the memory 8.

FIG. 1 shows a memory 8, a page management table for managing a block for each page of the memory 8 for each terminal 1, and a surplus management table. Memory 8 is optical disk 5
The pre-read data is stored page by page for each terminal. The workstation A pre-reads 5 pages A1 to A5, the workstation B pre-reads 2 pages B1 and B2, and the workstation C pre-reads 2 pages C1 and C2.
Each page management table manages up to 15 pages,
Pages over 16 are managed by a surplus management table provided in common for each workstation.

FIG. 3 is a diagram for explaining page management by weighting. (A) shows the pages preread by the workstations A, B, and C and the weighting. The weight indicates the number written in each page, and in this case, the number of preread pages matches the weight. The larger the weighting number,
The weight is low. (B) is an explanation when the workstation C requests 5 pages for prefetching. The minimum value of the weight of the workstation C is 6, as shown in (a), while the workstation A has 12 and the workstation B has 15, which are lower than the workstation C. For this reason, if the work A is divided by one page and the work B is divided by four, the weights of the respective work stations will be equal to 11. In this way, the pages with low weight of each workstation are managed so as to be passed to the workstation that outputs the request with high weight.

FIG. 4 is a diagram for explaining the management of one workstation. (A) is a figure explaining page number management of a page management table, (b) is a figure explaining weight management. The page management table manages up to 15 pages. In (a), the left end shows a state in which up to 10 pages have been read into the memory 8. Pages -1 to -5 are fictitious pages, which are provided for the purpose of weighting. The line on page 1 indicates the page that the terminal 1 is reading from the memory 8. In the center, up to 13 pages are read into the memory 8 and the terminal 1 is reading out 4 pages.
The fictitious page becomes -1 and -2. The right end is a state in which up to 16 pages are read into the memory 8 and the terminal 1 is reading out 7 pages. In this case, since one page is out of the management range of 15 pages, this is managed by the surplus table.

(B) corresponds to (a) and shows weighting of each page. The higher the weight, the lower the weight. In the case of the left end, pages 1 and 2, then -1 page,
Pages 3 and 4 are followed by page -2, and real pages and fictitious pages are weighted at a ratio of 2: 1. The center is the weighting when reading up to page 13 in (a). The meaning of providing a fictitious page is
This is so that the weights can be compared when the actual page is not read up to 15 pages and when another terminal is reading up to 15 pages.

For example, the left end of (b) is the page weight of workstation A, and the right end is the page weight of workstation C. The fourth page from the bottom of the left end, the third page, and the fourth page from the bottom of the right end, the ninth page, have the same weighting. In the case of the left end, if there is no third -1 from the bottom, the fourth page 3 becomes the third page and the weighting increases. In order to avoid this inconvenience, a fictitious page is provided and the weighting level is adjusted when 15 pages are not read.

FIG. 5 is a flow chart of this embodiment. First,
The terminal 1 checks whether the page to be read from the multi-deck unit 4 has already been read into the memory 8 (step 51),
If it has been read, the read page is transferred to the terminal 1 (step 52), the pages are arranged as shown in FIG. 4, and the weighting is updated (step 53). If it has not been read in step 51, it is checked whether there is a page to be read (step 5
4) If so, it is checked whether a memory for reading can be acquired (step 55), and if acquired, the page is read (step 56).

If the memory cannot be obtained in step 55, it is checked whether there is a protruding page which is more than 15 pages and is registered in the surplus management table (step 57). However, if it is read by another terminal 1 (step 58), the page is moved to the page management table of its own terminal.
(Step 59). In step 58, if the same page as the requested page is not read into the memory 8, the page in the surplus management table is deleted (step 60), the memory is acquired (step 55), and the requested page is read (step 55). 56).

If no extra page is registered in the surplus management table in step 57, it is checked whether there is a page weighted lower than the requested page in the page management table as described with reference to FIGS. 3 and 4 (step 61). If so, it is checked whether the requested page has already been read into the memory by another terminal 1 (step
62) If it is read, move to the page management table of the terminal that requested the page (step 63), if not read, delete the page with low weight (step 60), and acquire memory (step 60). 55), and read the page (step 56).

As described above, according to this embodiment, the following effects can be obtained. The management table for each terminal can be made smaller. Blocks (pages) outside the management range can be deleted without consideration of weighting and can be used by the requesting terminal. Since the number of blocks to be managed is limited, it is possible to shorten the time for determining the blocks to be deleted by comparing the weights. When the same information as the request information has already been read into the memory, the same information can be used simply by transferring the management information.

[0018]

As is apparent from the above description, the present invention manages the prefetch memory by providing a page management table that limits the number of pages to be managed and a surplus table that manages the pages outside the page management table. Can be done efficiently.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship among a memory, a page management table, and a surplus management table.

FIG. 2 is a configuration diagram of an electronic filing device that realizes the present exemplary embodiment.

FIG. 3 is a diagram illustrating page management by weighting.

FIG. 4 is a diagram for explaining transition of a page management table.

FIG. 5 is a diagram for explaining the operation of this embodiment.

[Explanation of symbols]

 1 terminal 2 file controller 3 multi-deck control unit 4 multi-deck unit 5 optical disc 6 transport mechanism unit 7 deck 8 memory 9 memory control unit

Claims (1)

Claim: What is claimed is: 1. A memory for storing pages prefetched from an electronic file, and data stored in the memory for each terminal accessing the electronic file is managed page by page for each terminal. By a page management table that manages a predetermined amount of pages for each terminal based on the weighting of each page, and a surplus management table that commonly manages pages exceeding this predetermined amount for each terminal. An electronic file device characterized by management.