JPH02307138A - Record control system for index forward compiling file - Google Patents

Abstract

PURPOSE:To add the new volumes in response to the increase of the number of records and to ensure the expansion properties by setting an index area and a data area to the different volumes. CONSTITUTION:A file control mechanism 13 is prepared together with a user program 14, the floppy disk drivers 16-1 and 16-2 which drive the volumes A and B, and a floppy disk controller (FDC) which controls both drivers 16-1 and 16-2. Then an index area 2 and a data area 5 are added to the volumes A and B respectively. Thus the new volumes are added in response to the increase of the number of records and the extension properties are ensured.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a data area and an index area storage area of an index sequential file stored in a storage medium such as a floppy disk, and in particular to a data area and an index area storage area. This invention relates to a record management method for an indexed sequential file in which files are stored in separate storage media.

(Prior Art) When creating a file on a floppy disk that allows direct access, indexed sequential files that allow random access to arbitrary records are often used.

FIG. 6 shows the physical structure of such an indexed sequential file on a floppy disk. One volume (floppy disk) 20 stores a dataset label 21 in which file attributes such as file names are stored, a subhead label (SHL) 22 in which information for managing free space, etc. is stored, keys, etc. An index h123 and a data area 24 in which records are stored are provided. The index area 23 is used from immediately after the subheader label 23 toward the end of the area, and the data area 24 is used from the end of the area toward the start.

(Problems to be Solved by the Invention) As described above, in the conventional index 111 m file, a data area and an index area are provided on the same volume. Therefore, it is not possible to store records that exceed the capacity of the volume, so there is no expandability.

The present invention has been developed in light of these circumstances, and its purpose is to provide a record management system for indexed sequential files that allows volumes to be added as the number of records increases.

(Means for Solving the Problems) In order to achieve the above object, the record management method for indexed sequential files of the present invention provides a data area and an index area in the same storage medium, and stores records in the data area. In the record management method for an indexed sequential file in which a key corresponding to the record is stored in the index area, the data area and the index area are provided in separate storage media.

(Operation) In the record management system for an indexed sequential file of the present invention, the data area and the index area are provided in separate storage media. Therefore, new volumes can be added as the number of records increases, providing expandability.

(Example) Next, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. In the figure, 13 is a file management R structure, 14 is a user program, 16-1.16-2 is a floppy disk driver that drives volumes A and B, and 15 is a floppy disk driver that controls the floppy disk driver 16-1.16-2. The file management mechanism 13, which is a floppy disk controller (referred to as FDC), includes a file area securing means 17, a file opening means 18, a record writing means 19, and a record reading means 20.

FIG. 2 shows the logical structure of a volume that stores indexed sequential files to which the present invention is applied. Volume A has index area 2, and volume B has data area 5.
are provided separately for each. In addition, in the same figure,
The same reference numerals as in FIG. 6 indicate the same parts.

FIG. 3 shows the concept of the logical structure of an indexed sequential file. Mask index 30 for volume A
, hierarchical cylinder indexes 31-1 to 31-
3 and track indexes 32-1 to 32-3, and volume B includes data records 33-1 to 33-6 storing data.

FIG. 4 shows an example of the configuration of the indexes (mask index 30, cylinder indexes 31-1 to 31-3, and track indexes 32-1 to 32-4). Each index is composed of a horizontal pointer 8 including a pointer PP and NP that mutually link each index, and entries 10-1 to 10-n including a pointer indicating a lower index, a key, etc.

FIG. 5 shows an example of the structure of the entries in FIG. 4. Each entry consists of a key part 12 and a pointer part 13. -Ir portion 12 stores a key. The mask index 30 and the pointer section 13 of the cylinder disks 31-1 to 31-3 point to the address where the track index is stored (that is, the volume A
track index 32-1).
The pointer section 13 of ~32-3 indicates the address storing the data record (that is, the address within volume B).

Next, the operation of securing a file area and storing data records in the embodiment shown in FIG. 1 will be described. First, a request for securing a file area is issued from the user program 14 to the file management mechanism 13. Then, the area securing means 17 receives and receives this request for securing a file area. Then, the FDC 5 is controlled to secure an index area in volume A loaded in the floppy disk driver 10-1 and a data area in volume B loaded in the floppy disk driver 16-2.
Next, go to the sub of volume A. The index area 1 is in the index area 1.
Information indicating that a data area has been provided is recorded on the subheter label 4 of volume B, and information indicating that a data area has been provided is recorded respectively. Therefore, volumes A and B have a configuration as shown in FIG.

Once the file area is secured, the user program 14 then sends a file open request to the file management machine! f4
13, the file open means 18 receives this file open request and sends the information in the label 1.4 to the sub volumes A and B via the FDC 15 and the floppy disk driver 16-1.16-2. to prepare for accessing each volume.

When such processing is completed and the user program 14 issues a record write request, the record storage means 19 stores the data and key received together with the record write request in the respective volumes. That is, the following process is performed. First, the receiver writes a record containing the received data and key to the unused area 6 of volume B, and updates the end address of the unused area in the sub label 4. For example, as shown in Figure 3, the key is "1".
Data record 33-1 containing "09" is stored.

Next, create an entry as shown in FIG. 5 that corresponds to this data record, and register this entry in a predetermined index. A sector address and a relative record number are stored, and the key section 12 stores the above-mentioned key '109J. Then, this entry is set to track index 3, as shown in Figure 3.
It is registered in 2-1. By repeating such operations, the volumes A and B will be in the state shown in FIG. 3.

Next, the operation when there is a request to read a record from the user program 14 will be explained. The record reading means 20 receives a record reading request including key information from the user program 14. Based on this key information, the mask index 30, cylinder index 31-1 to 31-3, track index 32-
1 to 32-3, find the desired data record, and pass the data record to the user program 14.

(Effects of the Invention) As described above, the record management method for an indexed sequential file of the present invention provides an index area and a data area in separate volumes. Therefore, new volumes can be added as the number of records increases, providing expandability.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of an embodiment of the present invention. Figure 2 is a diagram showing the logical structure of a volume that stores indexed sequential files to which the present invention is applied. Figure 3 is a conceptual diagram of the logical structure of indexed sequential files. FIG. 4 shows a mask index 30, cylinder indexes 31-1 to 31-3, and track index 32.
-1 to 32-4, Figure 5 is a diagram showing an example of the entry configuration in Figure 4, and Figure 6 is a diagram showing the logical structure of a volume that stores conventional index sequential files. be. 13...File management aam, 14...User program, 15...FDC117...File area securing means, 18...File opening means, 19...
Record writing means, 20...Record reading means. Agent Patent Attorney Honjo Brokerage Figure 1 # 1 ゝ Figure 3 Figure 4, 2, 10S Liu 4, /' Figure 6

Claims (1)

[Scope of Claims] Record management in an indexed sequential file in which a data area and an index area are provided in the same storage medium, records are stored in the data area, and keys corresponding to the records are stored in the index area. A record management method for an indexed sequential file, characterized in that the data area and the index area are provided in separate storage media.