Data processing: database and file management or data structures – Database design – Data structure types
Reexamination Certificate
1998-03-25
2002-09-03
Amsbury, Wayne (Department: 2171)
Data processing: database and file management or data structures
Database design
Data structure types
C707S793000
Reexamination Certificate
active
06446067
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to an information processing unit and information processing system, suitable for use in various information processing using Christian calendar year/date information, a method of correcting abnormality of Christian calendar year in the information processing unit, and a computer readable record medium in which is recorded a Christian calendar year abnormality correction program.
(2) Description of the Related Art
Up to now, information processing units have held date information and Christian calendar year information for use in information processing, although the Christian calendar year information has been often managed merely in lower two digits in such an information processing system that manages collectively file data usable and shared by a plurality of information processing units.
This aims to reduce information redundancy through management of the lower two digits only, since upper two digits of the Christian calendar year information will not change until the year 2000 arrives.
In other words, the above information processing unit or information processing system makes use of lower-two-digit Christian calendar year information to retain data in a file or to execute application processing, thereby achieving an effective resource utilization in both hardware and software.
According as the Christian calendar year approaches the year 2000, however, it has proved to be impossible to judge a difference between the year 1900 and the year 2000 from the above-described two-digit Christian calendar year management, so that any measures are desired which allow for both hardware and software of the information processing system.
In case of hardware specifications allowing automatic count of lower-two-digit only Christian calendar year information by a real time clock, it is possible for the unit with a CMOS (a buffer which saves data even in the event of the electrical source being cut off) in which “19” has been set fixedly as upper two digits to have accurate Christian calendar year information as long as the year 2000 is not reached, but impossible to distinguish between the year 2000 and the year 1900 since the intra-unit Christian calendar year information returns to the year 1900 once the Christian calendar year has reached the year 2000.
Thus, year 2005 information for instance will undesirably be registered as year 1905 information. In this case, any attempt to retrieve information indicative of the year 2005 may result in vain. Also, in case of deleting files having as their keys Christian calendar year comparison or Christian calendar year information through application processing, files undesired to delete may be deleted or files to be deleted may not be deleted because of the use of lower two digits only or erroneous Christian calendar year information as their keys.
In other words, it would be difficult for the user to discriminate from the data itself whether the Christian calendar year information is erroneous or not, so that files using Christian calendar year information as their keys may disappear or files desired to retrieve may not be retrieved the instant that the year 2000 has been reached in spite of ordinary use posing no problem.
In addition, in cases where software is employed to assist the hardware specifications, it would actually be difficult to deal with all the models. There are even cases where erroneous assist would occur.
In order to solve the above problems, at present an alarm may be issued or the software may be amended. However, in amending the software, there may also be a situation where it is actually necessary to completely revise the software installed in the hardware constituting the computer system.
In such an information processing system that includes a server unit accommodating a plurality of client units, with the continued advancement of the information processing system networking, the data management technique is shifting from one in which data are collectively managed at a single site (on the server unit side) toward one in which data are managed in each client unit in a decentralized manner. If each of the client units is located at the sites having different standard times, it is also necessary to adjust accordingly the time generated by a real time clock (RTC) of each client unit.
SUMMARY OF THE INVENTION
The present invention was conceived in view of the above problems. It is therefore an object of the present invention to provide an information processing unit capable of distinguishing between the year 1900 and the year 2000 even through software and hardware-based Christian calendar year information management in lower two digits, not four digits, a method of correcting abnormal Christian calendar year in the information processing unit, and a computer readable record medium having a Christian calendar year abnormality correction program recorded therein.
Another object of the present invention is to provide an information processing system consisting of a plurality of information processing units arranged at sites having different reference times, the system enabling the time management to be universally performed in conformity with the reference times at sites where the information processing units are arranged, while distinguishing between the year 1900 and the year 2000 in the same manner as the above case.
To this end, according to a first aspect of the present invention there is provided an information processing unit comprising a memory part for storing in a file format therein information processing data containing Christian calendar year information having first number of digits; an application processing part for executing application processing by use of Christian calendar year information having second number of digits, of the Christian calendar year information having first number of digits contained in the data stored in the memory part; and a file access control part for writing/reading file format data to/from the memory part in response to a request from the application processing part; the file access control part including a judgment part which upon a receipt of a request to read Christian calendar year information within a file stored in the memory part from the application processing unit, judges whether the Christian calendar year information in the memory part indicates a predetermined Christian calendar year onward; and a read Christian calendar year information output part which when it is judged in the judgment part that the Christian calendar year information indicates the predetermined Christian calendar year onward, generates Christian calendar year information having identification information indicative of that fact, to output it as read Christian calendar year information.
In this case, the predetermined Christian calendar year can be the year 2000. The Christian calendar year information having first number of digits may be four-digit Christian calendar year information, and the Christian calendar year information having second number of digits may be Christian calendar year information having second number of digits of said four-digit Christian calendar year information.
A restoration processing part may be provided which when the identification information is contained in Christian calendar year information constituting file format data in the memory part read by the application processing part, restores said Christian calendar year information into Christian calendar year information having first number of digits through interrupt processing, whereby it is possible even in the event of only lower-two-digit management of Christian calendar year information to distinguish between the year 1900 and a predetermined Christian calendar year.
The read Christian calendar year information output part may include a first read processing part for imparting the identification information to Christian calendar year information having second number of digits, of Christian calendar year information having first n
Amsbury Wayne
Fujitsu Limited
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