Electrical computers and digital processing systems: support – Clock – pulse – or timing signal generation or analysis
Reexamination Certificate
1999-03-12
2002-07-16
Gaffin, Jeffrey (Department: 2182)
Electrical computers and digital processing systems: support
Clock, pulse, or timing signal generation or analysis
C713S600000, C710S058000
Reexamination Certificate
active
06421786
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a virtual system time management system, a management method, and a recording medium for storing a management program which allow some application programs (hereafter called APs) to be executed based on the time of the system clock and some other APs to be executed based on a time virtually set up.
2. Description of the Related Art
In a conventional data processing system, it is requested to check and evaluate that all APs in the system will be executed correctly when the year 2000 comes.
This evaluation is done, for example, by forcing the date of the system clock in the data processing system to be changed to Dec. 31st, 1999 and then executing an AP across the midnight (until Jan. 1st, 2000 comes). This allows the user to check the AP for an error in the processing result.
In the above method, however, the change in the time of the system clock affects all APs to be executed in the data processing system, meaning that all APs are based on the changed time. In other words, once the system time is changed, the user cannot execute APs that must be executed based on the time before the change (such as production-run APs).
An earlier patent disclosure dealing with this is found in Japanese laid-open patent application heisei 9-171458. The technique disclosed in this patent application is that one computer system has multiple platforms each with its own system clock.
However, the technique disclosed in Japanese laid-open patent application heisei 9-171458 causes multiple platforms to share the resources of one computer system, such as the CPU and memory. Thus, an AP in each platform can use the amount of resources smaller than that allocated in the single-platform system. In such a system, there are performance problems such longer processing times.
SUMMARY OF THE INVENTION
It is an object of the present invention to enable an AP which performs operation based on the original system time and another AP which performs operation based on a changed system time to be executed concurrently in a data processing unit with a single system clock without having to change the system time of the system clock.
The first virtual system time management system according to the present invention for use in a data processing unit with a single system clock indicating the current date and time comprises virtual system time setting means for receiving, and storing in a virtual system time storage area, a date different from the current date indicated by said system clock and/or a time different from the current time indicated by said system clock from an input/output unit; and virtual system time converting means responsive to a system date acquisition request from a command or a job in execution for returning, when a date is stored therein, that date stored in said virtual system time storage area and responsive to a system time acquisition request from the command or the job in execution for returning, when a time is stored therein, the sum of the current time indicated by said system clock and that time stored in said virtual system time storage area.
The second virtual system time management system according to the present invention for use in a data processing unit with a single system clock indicating the current date and time comprises virtual system time setting means for receiving, and storing in a virtual system time storage area, a date different from the current date indicated by said system clock and/or a time different from the current time indicated by said system clock from an input/output unit; and virtual system time converting means responsive to a system date acquisition request from a command or a job in execution for returning, when a date is not stored in said virtual system time storage area, the current date indicated by said system clock and responsive to a system time acquisition request from the command or the job in execution for returning, when a time is not stored in said virtual system time storage area, the current time indicated by said system clock.
The third virtual system time management system according to the present invention for use in a data processing unit with a single system clock indicating the current date and time comprises a virtual system time storage area containing a plurality of entries each being composed of a command or job identifier field, a date storage field, and a time storage field; virtual system time setting means for receiving a command or job identifier from an input/output unit and storing the identifier into the command or job identifier field of an entry of said virtual system time storage area, for, when receiving a date different from the current date indicated by said system clock with the command or job identifier from the input/output unit, storing that date into the date storage field of the entry into which the command or job identifier is stored for, when receiving a time different from the current time indicated by said system clock with the command or job identifier from the input/output unit, storing that time into the time storage field of the entry into which the command or job identifier is stored; and virtual system time converting means responsive to a system date acquisition request from a command or a job in execution for returning, either when a date is not stored in said date storage field of the entry corresponding to the identifier of the command or the job in said virtual system time storage area, the current date indicated by said system clock, or when a date is stored therein, that date stored in said date storage field and responsive to a system time acquisition request from the command or the job in execution for returning, either when a time is not stored in said time storage field of the entry corresponding to the identifier of the command or the job in said virtual system time storage area, the current time indicated by said system clock, or when a time is stored therein, that time stored in said time storage field.
The first virtual system time management method according to the present invention comprises, in a data processing unit with a single system clock indicating the current date and time, receiving, and storing in a virtual system time storage area, a date different from the current date indicated by said system clock and/or a time different from the current time indicated by said system clock from an input/output unit; and, in said data processing unit, responsive to a system date acquisition request from a command or a job in execution for returning, when a date is stored therein, that date stored in said virtual system time storage area and responsive to a system time acquisition request from the command or the job in execution for returning, when a time is stored therein, the sum of the current time indicated by said system clock and that time stored in said virtual system time storage area.
The second virtual system time management method according to the present invention comprises, in a data processing unit with a single system clock indicating the current date and time, receiving, and storing in a virtual system time storage area, a date different from the current date indicated by said system clock and/or a time different from the current time indicated by said system clock from an input/output unit; and, in said data processing unit, responsive to a system date acquisition request from a command or a job in execution for returning, when a date is not stored in said virtual system time storage area, the current date indicated by said system clock and responsive to a system time acquisition request from the command or the job in execution for returning, when a time is not stored in said virtual system time storage area, the current time indicated by said system clock.
The third virtual system time management method according to the present invention comprises, in a data processing unit with a single system clock indicating the current date and time, receiving a command or job identifier from an input/
Gaffin Jeffrey
Mai Rijue
NEC Corporation
Young & Thompson
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