JPS6226488B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data writing method in an index sequential data set of an auxiliary storage device in an electronic computer.

There are various types of external storage devices for electronic computers, and 100 shown in Figure 1 is a schematic depiction of a large-capacity storage device in an index sequential organization set. The contents of the device 100 will be described below.

30, 31, 3 in the management area indicated as 01
2...... indicates data areas 02, 03,
04... Each area (A, B, C, in Figure 1)
This is an area for managing the parts shown as …….

By the way, each of the above areas 01, 02, 03, . . . has a configuration as shown in FIG. 2, and each track has one head 101, 102,
103, 104, 105...... each head corresponds to a central processing unit (hereinafter referred to as CPU) 1
It is connected to 11.

The topmost track in FIG. 2 is called the index area, and each of the second, third, fourth, etc.
The last data written in 4, i.e. data 9 shown as 21, data 2 shown as 22
Data 33 shown as 0, 23 is called a key, and 21', 22', 2 are shown in the index area.
It is registered as shown as 3'......

There is a convention that the data arranged in each track of the prime area is arranged in order from smallest to largest as shown in FIG. 2 as 1, 2, 3, 4, . . . . Therefore, for example, if you want to find out where the data 13 is stored, if you compare the data 13 with the key data 20 and 9, you will find that 13 is larger than 9 and smaller than 20, so it is in the third row. track 13
It is immediately obvious that something is inside.

Now, suppose that, as shown in FIG. 2, data 6 and 7, for example, are missing in the track shown as 12 in this prime area. In this case, in order to write the data 6 and 7 into the track 12, each data in the track 12 must be written once through the head 101.
Each data must be read to the main memory in the CPU, reorganized in the CPU, and then written to the track 12 again. In this case, for example, if data 6 is written to the track 12,
Since there is no room in the track, other data other than 6, such as data 7, will overflow, so other data 1, 2, 3, 4, 5, 6, 7 will be sent from the CPU via the head 102. .

However, if a system failure such as a power outage occurs while this data 7 is still being held in the memory of the CPU 111, the data 7 will be lost. Therefore, especially if the data that overflows after reorganization is data that was in the original prime area, this will disappear after the reorganization data is written to the prime area but before it is written to the overflow area. However, the disadvantage was that the initial settings had to be made all over again.

The present invention has been made in view of these drawbacks, and is intended to be used when writing additional data to an auxiliary storage device of a computer that includes an auxiliary storage device mainly consisting of an index area, a prime area consisting of a plurality of tracks, and an over area. After reorganizing the additional data and the data on the track in the main memory of the computer, the data overflowing from the prime area is written in the prime area in advance to the overflow area. The purpose is to provide a data writing method in which the data is written and then the reorganized data is rewritten in the prime area, and this method will be described below.

It is determined by the CPU during data reorganization that either data 6 or 7 is unlikely to be written into track 12. In this way, for example, if it is unlikely that data 7 can be written to track 12, the overflowing data 7 will be written first when the data reorganization in the CPU is completed.
The data is output from the CPU 111 and written via the head 105 into the portion shown as 16 in the over area. After that, the reorganized data other than the above data 7 are transferred from the CPU 111 to the track 12 in the prime area via the head 102.
Rewrite inside.

In this way, even if the electronic computer system goes down due to a power outage as described above, the overflowing data 7 will be written to the overflow area, so the data 7 will not be lost. Therefore, at least the data contents in the original prime area before addition are always left on the storage device, making it possible to stably write reorganized data in the index sequential data set. can.

Note that in the above example, data 7 overflows, but for example, if data 9 overflows, it is this data 9 that should be written to the overflow area. In this case, the key in track 12 will be changed to data 8, so data 8 is written via head 102 and CPU 111 to the portion shown as 21' in the index area.

According to the data writing method according to the present invention described above, it is possible to prevent data files from being destroyed in the event of a system failure, and therefore, great practical effects can be expected.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing a mass storage device in an index sequential organization set, and FIG. 2 is a diagram showing the contents of a data area of one of the mass storage devices. In the figure, 01 is the management area, 02, 03, 0
4...... is the data area, 1 to 9, 11 to 20, 3
3 is data, 21 is data 9, 22 is data 2
0, 23 are data 33, 101, 102, 10
3, 104, and 105 are heads, 100 is a mass storage device, and 111 is a CPU.

Claims (1)

[Claims] 1. When writing additional data to the auxiliary storage device of a computer that includes an auxiliary storage device mainly consisting of an index area, a prime area consisting of multiple tracks, and an over area, the additional data is written in the main memory of the computer. Then, after reorganizing the data on the track mentioned above, by writing additional data into the prime area, the data overflowing from the prime area is written in advance to the overflow area, and then the above regenerated data is reorganized. A data writing method characterized by rewriting data to a prime area.