JP3188659B2 - Data correction method, data display method, data reading method, and data recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data correction method for correcting date data to correspond to the year 2000.
The present invention relates to a data display method for displaying a date based on the date data, a data reading method for reading the date data, and a data recording method for recording the date data.

[0002]

2. Description of the Related Art At present, only the last two digits of the Christian era are shown in the date expression format used in computers and the like.
7/08/11 ". In Europe and the United States, only the last two digits are often used to represent the Christian era, and before 1988, the last two digits were stipulated by ISO and JIS standards. Until around this time, hardware costs were high, and it was the background that we wanted to reduce the data length as much as possible.

However, in such a date representation method, in the year 2000, the last two digits are "0".
0 ", the computer recognizes that the year is 1900 AD, and various obstacles occur in data and programs currently used. For example, comparison of date size, date form printing, age calculation processing, Erroneous processing occurs in the interest rate calculation processing or the Japanese calendar year conversion processing. Specifically, in the Japanese calendar year conversion process, 199
Until 1999, 1999 can be correctly converted to 1999, but in 2000, a completely wrong conversion will be performed as in Heisei-1988.

[0004] For this reason, various methods have been proposed to make date data correspond to the year 2000. Specifically, the data of the year represented by the last two digits of the Christian era is
What was changed to a digit and expressed as "97" was changed to "199".
7 ".

[0005]

However, as described above, changing the year data from two digits to four digits requires a great deal of time and effort since all date data must be rewritten. In addition, since the year data increases to four digits, the record length of the date data increases, so if there is not enough space on the disk where the data including the date data is stored, save the data to another disk. It is necessary to do it again. Further, in the job control statement for controlling the job of the program, for example, data indicating the type of data is attached after the date data “000722”.
In order to specify a position of a data category such as "AB123C-1", a specification such as "7th to 14th digit" is performed. However, when the year data is increased to four digits, the above data becomes "2000722 AB12
3C-1 ", and the classification position becomes" the ninth digit to the seventeenth digit ", so that the job control statement needs to be rewritten.

The present invention has been made in view of the above circumstances, and provides a data correction method, a data display method, a data reading method, and a data recording method capable of coping with the year 2000 without changing the data length. It is intended for that purpose.

[0007]

In packed date data, two numbers can be represented by one byte. In a 4-byte area, a code is assigned to 1/2 byte and 1 byte. , Two-digit days are assigned to one byte, two-digit months are assigned to one byte, and the last two digits of the year are assigned to one byte, so that the remaining half-byte area is not used. The present invention has been made focusing on this point.

That is, in the data correction method according to the present invention, a plus / minus sign is set in a half-byte area, a two-digit day is set in a one-byte area, and a two-digit month is set in a one-byte area.
A method for correcting packed date data composed of a total of 4 bytes in which the last two digits of the Christian era are respectively allocated to a byte area, wherein the remaining half of said date data is １ ／
The first two digits of the Christian era are encoded and assigned to a byte area.

A data display method according to the present invention is a method for displaying a date based on the above-mentioned date data in a pack format, wherein the data allocated to the remaining half-byte area of the date data is provided. , The first two digits of the Christian era are displayed.

Further, the data reading method according to the present invention comprises:
A method for reading date data in a pack format as described above, wherein the first two digits of the Christian era are read based on data stored in a remaining half-byte area of the date data. .

A data recording method according to the present invention is a method for recording date data in a pack format as described above, wherein the first two digits of the Christian era are encoded in a remaining half-byte area of the date data. It is characterized by recording.

[0012]

According to the present invention, in the packed date data, the first two digits of the Christian era are encoded and assigned to a half-byte area that is not currently used. Specifically, when the data of the half-byte area is "0", it indicates the year 1900, and when it is "1", it indicates the year 2000.
As described above, since the first two digits of the Christian era are encoded and assigned to areas that are not currently used in the pack format date data, the date reading program can be modified with only a slight change. Modify date data without changing the data length,
Display, reading and recording can be done for the year 2000. Further, since there is no need to change the data length, it is not necessary to rewrite the data or change the job control statement as described above. As a result, the change work becomes almost unnecessary, and the labor cost can be greatly reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing packed date data changed by the data correction method according to the embodiment of the present invention. Here, the pack format is exactly pack 1
0-base notation, which refers to a method of assigning 4 bits to each of two consecutive decimal digits and expressing them in one byte.

As shown in FIG. 1, packed date data is 4-byte data composed of eight 1 / 2-byte areas 1A to 4B, and one cell in FIG. 1 indicates 1/2 byte. is there. In the area 1A, the sign of positive / negative, in the area 1B, the number of the ones place of the date, in the area 2A, the number of the tens place of the date, in the area 2B, the number of the ones place of the month, The area 3A is assigned the number of the tens place of the month, the area 3B is assigned the number of the ones place of the Christian era, and the area 4A is assigned the number of the tens place of the Christian era.

In the current pack format date data, the year is represented by only the last two digits, so the regions 3B and 4
Although the year can be expressed only by using the letter A, it cannot correspond to the year 2000.

Therefore, in the present embodiment, the date data can be made to correspond to the year 2000 by encoding and assigning the first two digits of the year to the unused area 4B. is there. That is, as shown in Table 1 below, the data lengths of the date data at least until the 2800s are set by associating the number of data with the first two digits of the Christian era as shown in Table 1 below. Can be expressed without changing the date.

[0018]

[Table 1]

For example, when 0 is stored in the area 4B as shown in FIG. 1, by reading the date data shown in FIG. 1, the date is represented as "1997/08/11". When 1 is stored in the area 4B as shown in 2, the date is represented as "2000/08/11".

In order to read the date from the date data corrected in this way, it is sufficient to slightly change the program so that the data in the area 4B in the pack format data is also read. Also,
When recording date data, the program may be slightly changed so that data can be recorded in the area 4B.

As described above, according to the present embodiment, the date data can be corrected, displayed, read, and recorded without changing the data length of the date data so as to correspond to the year 2000. Work such as rewriting and change of the job control statement is almost unnecessary, thereby shortening the period of the change work and greatly reducing labor costs.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of packed date data corrected according to the embodiment;

FIG. 2 is a schematic diagram illustrating another example of packed date data corrected according to the embodiment;

[Explanation of symbols]

 1A-4B data area

Claims (4)

(57) [Claims] 1. A sign of plus or minus in a half-byte area is 1
Packed date data consisting of a total of 4 bytes consisting of a 2-digit day in the byte area, a 2-digit month in the 1-byte area, and the last two digits of the year in the 1-byte area A data correction method, wherein the first two digits of the Christian era are encoded and assigned to a remaining half-byte area of the date data. 2. The method according to claim 1, wherein the sign of the sign is 1 in a half-byte area.
Packed date data consisting of a total of 4 bytes consisting of a 2-digit day in the byte area, a 2-digit month in the 1-byte area, and the last two digits of the year in the 1-byte area A method for displaying a date based on data assigned to a remaining half-byte area of the date data, based on the date, wherein the first two digits of the year are displayed. 3. The sign of plus or minus in the area of 1/2 byte is 1
From packed date data consisting of a total of 4 bytes in which a 2-digit day is assigned to a byte area, a 2-digit month is assigned to a 1-byte area, and the last two digits of the year are assigned to a 1-byte area What is claimed is: 1. A data reading method, comprising reading the first two digits of the Christian era based on data stored in a remaining half-byte area of the date data. 4. A plus / minus sign in a 1/2 byte area is set to 1
A 2-digit date is assigned to the byte area, a 2-digit month is assigned to the 1-byte area, and the last two digits of the year are assigned to the 1-byte area, and packed date data consisting of all 4 bytes is recorded. A data recording method, wherein the first two digits of the Christian era are encoded and recorded in a remaining half-byte area of the date data.