JPH063588B2 - Extent duplication check method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extent duplication checking method for detecting duplication of extents of files in a mass storage device.

(Prior Art) Conventionally, a method of inspecting the duplication of the extent of each file in a mass storage device has been as follows. That is, first, the start addresses of extents of all files in the mass storage device are converted into relative start track addresses, and the end addresses of extents are converted into relative end track addresses.

After that, the above addresses are sequentially stored in the extent cable, sorted by the relative start track address, and the extent overlap is checked by comparing the values of the continuous relative end track address and the relative start track address. .

(Problems to be Solved by the Invention) In the above-described conventional extent duplication check method, since the relative start track address and relative end track address of the extents of all files are stored in the extent table, the number of extents of the file is reduced. The increase has the drawback of requiring a larger extent table area.

An object of the present invention is to read the extent information of each file in the mass storage device, store the read extent information, manage the usage status of the tracks in the mass storage device, and store the above information. Check the duplication between the existing extent information and the above-mentioned managed information, store the extent information in which duplication is detected, and edit and output the duplication status to eliminate the above-mentioned drawbacks and to reduce the size of the extent cable area to an extreme extent. An object of the present invention is to provide a duplication check method for extents configured so as not to increase.

(Means for Solving the Problem) The extent duplication inspection method according to the present invention comprises a mass storage device, extent information reading means, extent information storage means, track usage status storage means, track usage status collation means, Duplicate extent storage means,
It is configured by including a duplication extent reflection means and a duplication status edit output means.

The mass storage device stores a plurality of files in the storage area and also stores extent information in the VTOC.

The extent information reading means is for reading the extent information of a file in the mass storage device.

The extent information storage means is for storing the extent information read by the extent information reading means.

The track usage status storage means is for storing extent information for managing the usage status of the tracks in the mass storage device.

The track usage status collating means updates the extent information stored in the extent information storage means so that the corresponding bits in the track usage status storage means, where each bit corresponds to each track on the volume, indicate the usage status. This is for detecting the occurrence of duplication when the bit to be updated already indicates the in-use state.

The duplication extent storage means is for storing the extent information in which duplication is detected by the track usage status collation means.

The overlapping extent reflecting means is for updating and reflecting the corresponding bit on the track use status storing means to the extent information stored in the overlapping extent information storing means so as to indicate the use state.

The duplication status edit / output means is for editing and outputting the extent information in which duplication is detected, which is stored in the duplication extent storage means.

(Example) Next, this invention is demonstrated with reference to drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the extent duplication check method according to the present invention. In FIG. 1, 1 is a mass storage device, 2 is a VTOC containing extent information of all files existing in the mass storage device 1, 3 is extent information reading means, 4 is extent information storage means, and 5 is Track usage status storage means 6, track usage status collation means, 7 overlapping extent storage means, 8 overlapping extent reflection means, 9 overlapping status edit output means, and 10 a print image output device.

The operation of each means shown in FIG. 1 will be described below.

In FIG. 1, the extent information stored in the VTOC 2 of the mass storage device 1 is read by the extent information reading means, stored in the extent information storage means 4, and the track usage status collating means 6 is operated. The track usage status collating means 6 uses the extent information stored in the extent information storage means 4 to reflect in the track usage status storage means 5 that each track occupied by the extent is in use. The corresponding instruction bit of the track usage status storage means 5 is updated to indicate the usage status.

When updating to the in-use state, it is checked whether the above-mentioned instruction bit is already in the in-use state, and if it is already in the in-use state, it is determined that the extents overlap. Therefore, the track usage status matching unit 6 converts the start address of the extent of the extent information into a relative start track address, converts the end address of the extent into a relative end track address, and stores it in the duplicated extent information storage unit 7.

The above processing is repeatedly executed for the extent information of each file of VTOC2.

When the processing of all extents is completed, the following processing is performed in order to find the extent that is the partner of the duplicated extent. That is, after the track usage status storage means 5 is initialized, the extent information stored in the overlap extent information storage means 7 is reflected in the track usage status storage means 5 by the overlap extent reflection means 8.

This means that the corresponding bits in the track usage status storage means are turned on for all extents stored in the overlapping extent information storage means. afterwards,
Again, the extent information reading means 3 causes the VTOC
The extent information of each file No. 2 is sequentially read again, and the track usage status collating means 6 is operated. Again, VTOC
When processing of all extent information on 2 is completed,
The duplication status edit output means 9 is operated. The duplication status edit output means 9 sorts the duplication extents stored in the duplication extent information storage means 7 by relative start track address, and compares the magnitude relationship between the values of the continuous relative end track address and the relative start track address. By doing so, the overlap of the extents is inspected, the print image is edited, and the result is output to the print image output device 10.

(Effects of the Invention) As described above, the present invention uses a table in which each track in a mass storage device is associated with an instruction bit, and stores only overlapping extent information in a storage area. There is an effect that it is possible to perform the overlap check of the extents in the mass storage device by using a certain storage area without depending on the number of extents in the mass storage device.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an extent duplication check method according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Large-capacity storage device, 2 ... VTOC 3 ... Extent information reading means 4 ... Extent information storage means 5 ... Track usage status storage means 6 ... Track usage status collation means 7 ... Overlap extent information storage means 8 ... Overlap extent reflection means 9 … Overlap status edit output means 10… Print image output device

Claims (1)

[Claims] 1. A mass storage device for storing a plurality of files in a storage area and for storing extent information in a VTOC, and extent information reading for reading extent information of the file in the mass storage device. Means, extent information storage means for storing extent information read by the extent information reading means, and track usage status storage for storing extent information for managing the usage status of tracks in the mass storage device Means and the extent information stored in the extent information storage means, each bit corresponds to each track on the volume, and the corresponding bit in the track usage status storage means is updated so as to indicate the usage state. ,
Track usage status collating means for detecting the occurrence of duplication when the bit to be updated already indicates the busy status; and for storing extent information in which duplication is detected by the track usage status collating means. A duplicated extent storage means; a duplicated extent reflection means for updating the extent information stored in the duplicated extent information storage means so that a corresponding bit in the track usage state storage means indicates a usage state; An extent duplication inspection method, comprising: duplication status edit output means for editing and outputting the extent information in which the duplication is detected stored in the duplication extent storage means.