US 5,675,727 A · Difference recording apparatus having a processing unit, recording unit, log update section, and log comparator using a classification key in a log of input data

Abstract

A difference recording apparatus includes a log comparator, a processing unit, a recording unit, and a log update section. The log comparator detects a log difference by using a classification key in a log of input data. The processing unit restores the log by using difference data from the log comparator. The recording unit records the log restored by the processing unit. The log update section limits recording of a log of identical data in the recording unit within a unit time on the basis of the presence/absence of a difference detected by the log comparator and an upper limit of log acquisition.

Drawings

Drawings are temporarily unavailable. Open the PDF at USPTO

Drawings

Claims4

Dependent claims

A difference recording apparatus, comprising:

difference detection means for detecting a log difference by using a classification key in a log of input data;
processing means for restoring the log by using difference data from said difference detection means;
recording means for recording the log restored by said processing means;
recording limiting means for limiting recording of a log of identical data in said recording means within a unit time on the basis of the presence/absence of a difference detected by said difference detection means and an upper limit of log acquisition;
and
timepiece means for repeatedly counting a unit time,
wherein said recording limiting means limits recording of the log of identical data within each unit time counted by said timepiece means;
wherein said recording limiting means comprises a log update section for updating a log record, said log update section performing update processing for a log recording area in said recording means after the lapse of the unit time in a recording mode,
wherein said processing means records difference data associated with log data which is being recorded in said recording means, when new data is input in a log recording mode, under a condition that the data have identical classification keys, and the upper limit of log acquisition has not been reached,
wherein said processing means updates only a loss counter corresponding to log data of said recording means, when new data is input in the log recording mode, under one of conditions that the data have identical classification keys and no difference data is present, and that the upper limit of log acquisition has been reached, and
wherein the difference is stored in the difference data and the log, which is considered identical according to the classification key, is deleted and the number of losses are counted by the loss counter, before the time passes for the renewal by the timepiece means, and wherein the difference of the input data is stored in another area and when it is considered that there is no input data difference, the data is deleted to secure a save area.

8 more elements

Dependencies are inferred from the claim text.

Description2,114 words

Summary827 words

#The present invention relates to a difference recording apparatus and, more particularly, to a difference recording apparatus in a switching system or computer system which includes a processing unit for recording or displaying a log of data including a message.

#In update operations, upon occurrence of various kinds of failures, log data are used to restore databases and files to their normal states. If, for example, a central processing unit stops while a database is updated, the database is restored to a normal state by using a log. Also, if past operations are to be canceled after the execution of processing based on a program, the restoration of the initial normal state is required. In such a case as well, a log is used. In this case, a log means a history of update operations in executing a certain operation. This log includes two kinds of log data, i.e., AI (After Image) log data and BI (Before Image) log data.

#AI log data is used for a roll forward. That is, every time the contents of a database are updated, the contents after the update processing are stored as log or the like. BI log data is used for a rollback. That is, every time the contents of a database are updated, the contents before the update processing are stored as a log or the like.

Brief description of the drawings4 figures

#FIG. 1 is a block diagram showing a difference recording system according to an embodiment of the present invention;

#FIGS. 2A, 2B, and 2C are views each showing a data format of control data used in the apparatus in FIG. 1;

#FIG. 3 is a flow chart for explaining the control operation of the difference recording apparatus in FIG. 1; and

Detailed description1,213 words

#The present invention will be described below with reference to the accompanying drawings.

#FIG. 1 shows a difference recording apparatus according to an embodiment of the present invention.

#Referring FIG. 1, this embodiment comprises a data source 1 for generating data on which log acquisition is based, a recording unit 4 for recording log data of the data from the data source 1, log difference data, the upper limit of recording/acquisition of the log data and difference data, and the like, a timepiece unit 2 for generating a periodic output for updating the recording unit 4 with time, and a processing unit 3 for recording the log data and difference data in the recording unit 4 every unit time to realize a reduction in recording amount and limitation of recording.

Facts

Application

08/445,544Filed 22 May 1995

Priority

JP 6-10734223 May 1994

Granted

7 Oct 1997

Term ended

22 May 2015

Estimated · how

Pre-1995 term; greater of 17 years from grant or 20 years from filing when eligible. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification3 codes

G06F 16/2358
Updating: change logging, detection, and notification
G06F 11/1471
Error detection or correction of the data by redundancy in operations: involving logging of persistent data for recovery
G06F
Computing and data processing

Description2,114 words

Summary827 words

Brief description of the drawings4 figures

#FIG. 1 is a block diagram showing a difference recording system according to an embodiment of the present invention;

#FIGS. 2A, 2B, and 2C are views each showing a data format of control data used in the apparatus in FIG. 1;

#FIG. 3 is a flow chart for explaining the control operation of the difference recording apparatus in FIG. 1; and

Detailed description1,213 words

#The present invention will be described below with reference to the accompanying drawings.

#FIG. 1 shows a difference recording apparatus according to an embodiment of the present invention.

Difference recording apparatus having a processing unit, recording unit, log update section, and log comparator using a classification key in a log of input data

Life of this patent

Difference recording apparatus having a processing unit, recording unit, log update section, and log comparator using a classification key in a log of input data

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims4

Description2,114 words

Drawings

Classification3 codes

Life of this patent

Description2,114 words