Method of restoring memory to a previous state by storing previous data whenever new data is stored

• US 6,594,781 B1
• Filed: 02/02/2000
• Issued: 07/15/2003
• Est. Priority Date: 03/31/1999
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Yasutomi, Masato, Bando, Chikayasu, Komasaka, Toshio, Miyamoto, Takashi
• Primary Examiner(s): Beausoliel, Robert
• Assistant Examiner(s): CHU, GABRIEL L
• Application Number:
  US09/496,332
• Time in Patent Office: 1,259 Days
• Field of Search: 714/2, 714/6, 714/15, 714/19, 714/20
• US Class Current: 714/19
• CPC Class Codes: G06F 11/1433 during software upgrading
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 8/62 Uninstallation

Abstract

A computer comprises a write monitor unit for monitoring a data write operation into an operating system file, an update data file for storing update data upon detection of a data write operation, an update-log file for storing the history information for the update data in the case where the update data is stored, and a read monitor unit for reading data from the update data file in the case where the history information for the data to be read from the operating system file is stored and reading data from the operating system file in the case where the history information is not stored.

Claims

1. A computer comprising:

a storage medium; and

a controller coupled to said storage medium and capable of performing the following operations;

(i) storing in said storage medium, in the case where data used for the operation of the computer itself is replaced by writing update data, the update data, updated data replaced by the update data, and non-updated data not yet replaced by the update data;

(ii) reading, when executing data that is read out from said storage medium, the update data, if any, corresponding to the data to be read and the non-updated data corresponding to said data to be read in the absence of said update data;

(iii) discarding the update data in response to a first instruction, if any, to restore said storage medium to its initial status;

(iv) discarding the update stored in said storage medium after a designated arbitrary time point in response to a second instruction, if any, to restore said storage medium to the status at the designated arbitrary time point; and

(v) replacing the updated data with corresponding update data in response to a third instruction, if any, to update said storage medium.

2. A computer comprising:

data storage means for storing, in the case where data used for the operation of the computer itself is replaced by writing update data, the update data, updated data replaced by the update data, and non-updated data not yet replaced by the update data;

read monitor means for reading the update data, if any, corresponding to the data to be read and the non-updated data corresponding to said data to be read in the absence of said update data, when executing data that is read out from said data storage means; and

repair means for;

discarding the update data in response to a first instruction, if any, to restore said data storage means to its initial status,

discarding the update data stored in said data storage means after a designated arbitrary time point in response to a second instruction, if any, to restore said data storage means to the status at the designated arbitrary time point, and

replacing the updated data with corresponding update data in response to a third instruction, if any, to update said data storage means.

3. A computer comprising:

a storage medium; and

a controller coupled to said storage medium and capable of performing the following operations;

(i) storing data used to operate the computer itself in said storage medium;

(ii) monitoring that the data stored in said storage medium is replaced by writing update data that corresponds to the data that is stored;

(iii) storing the update data in said storage medium upon detection that a data updating process is to be performed;

(iv) storing in said storage medium history information of the update data in the case where the update data is stored in said storage medium;

(v) reading the update data from said storage medium in the case where the history information for the update data is stored in said storage medium and reading non-updated data from said storage medium in the case where the history information for the update data is not stored in said storage medium, when executing data that is read out from said storage medium;

(vi) discarding the update data and the history information in response to a first instruction, to restore said storage medium to its initial status;

(vii) discarding the history information stored after a designated arbitrary time point and the corresponding update data in response to a second instruction, to restore said storage medium to the status at the designated arbitrary time point; and

(viii) replacing the non-updated data with the update data and discarding the update data and the history information in response to a third instruction, to update said storage medium.

4. A computer comprising:

operating system storage means for storing the data used to operate the computer itself;

write monitor means for monitoring that the data stored in said operating system storage means is replaced by writing update data that corresponds to the data that is stored;

update data storage means for storing the update data in the case where said write monitor means detects that a data updating process is to be performed;

update log storage means for storing history information of the update data in the case where the update data is stored in said update data storage means;

read monitor means for reading the update data from said update data storage means in the case where the history information for the update data is stored in said update log storage means and reading non-updated data from said operating system storage means in the case where the history information for the update data is not stored in said update log storage means, when executing data that is read out from said operating system storage means;

repair means for;

discarding the contents stored in said update data storage means and said update log storage means in response to a first instruction, if any, to restore said operating system storage means to its initial status,

discarding the history information after a designated arbitrary time point stored in said update log storage means and the update data stored in said update data storage means in response to a second instruction, if any, to restore said operating system storage means to the status at the designated arbitrary time point, and

replacing the non-updated data stored in said operating system storage means with the update data stored in said update data storage means while at the same time discarding the contents stored in said update data storage means and said update log storage means in response to a third instruction, if any, to update said operating system storage means.

5. A computer comprising:

a storage medium; and

a controller coupled to said storage medium and capable of performing the following operations;

(i) storing data used to operate the computer itself in said storage medium;

(ii) monitoring that the data stored in said storage medium is replaced by writing update data that corresponds to the data that is stored;

(iii) storing in said storage medium updated data which is included in the data stored in said storage medium and replaced by the update data, in the case where the update data is written in said storage medium;

(iv) storing history information of the updated data in said storage medium in the case where the updated data is stored in said storage medium;

(v) replacing the update data with the updated data stored in said storage medium and discarding the updated data that is stored in the storage medium and the history information in response to a first instruction to restore, said storage medium to its initial status;

(vi) replacing the update data with the updated data stored after a designated arbitrary time point in accordance with the history information stored in said storage medium and discarding the history information after the designated arbitrary time point and the updated data that is stored in the storage medium in response to a second instruction to restore said storage medium to the designated arbitrary time point; and

(vii) discarding the updated data and the history information in response to a third instruction to update said storage medium.

6. A computer comprising:

operating system storage means for storing data used to operate said computer itself;

write monitor means for monitoring that the data stored in said operating system storage means is replaced by writing update data that corresponds to the data that is stored;

updated data storage means for storing updated data which is included in the data stored in said operating system storage means and replaced by the update data in the case where said write monitor means detects that the update data is written;

updated log storage means for storing history information of the updated data in the case where the updated data is stored in said updated data storage means; and

repair means for;

replacing the update data stored in said operating system storage means with the updated data stored in said updated data storage means and discarding the contents stored in said updated data storage means and said updated log storage means in response to a first instruction, if any, to restore said operating system storage means to its initial status,

replacing the update data stored in said operation system storage means with the updated data stored in said updated data storage means after a designated arbitrary time point in accordance with the history information stored in said updated log storage means and discarding the history information after the designated arbitrary time point stored in said updated log storage means and the updated data stored in said updated data storage means in response to a second instruction, if any, to restore said operating system storage means to the status at the designated arbitrary time point, and

discarding the contents stored in said updated data storage means and said updated log storage means in response to a third instruction, if any, to update said operating system storage means.

7. A computer network system comprising:

a first storage medium;

a second storage medium;

a third storage medium;

a plurality of computers including a computer to be monitored; and

a line for interconnecting said first storage medium, said second storage medium, said third storage medium and said plurality of the computers;

wherein said computer to be monitored includes a first controller capable of performing the following operations;

(i) storing data used to operate said computer itself in said first storage medium;

(ii) monitoring that the data stored in said first storage medium is replaced by writing update data therein that corresponds to the data that is stored;

(iii) monitoring that the data is read from said first storage medium;

(iv) storing the update data in said second storage medium upon detection that a data updating process is to be performed in said first storage medium;

(v) storing history information of the update data in said third storage medium in the case where the update data is stored in said second storage medium;

(vi) reading the update data from said second storage medium in the case where the history information for the update data from said first storage medium is stored in said third storage medium, when reading the data from said first storage medium; and

(vii) reading non-updated data from said second storage medium in the case where the history information for the update data is not stored in said third storage medium, when reading the data from said first storage medium;

wherein any one of said plurality of the computers includes a second controller capable of performing the following operations;

(viii) discarding the update data stored in said second storage medium and the history information stored in said third storage medium in response to a first instruction to restore said first storage medium to its initial status;

(ix) discarding the history information, which is stored in the third storage medium, after a designated arbitrary time point and the update data, which is stored in said second storage medium, in response to a second instruction to restore said first storage medium to its initial status at the designated arbitrary time point; and

(x) replacing the non-updated data stored in said second storage medium with the corresponding update data stored in said second storage medium and discarding the update data stored in said second storage medium and the history information stored in said third storage medium in response to a third instruction to update said first storage medium.

8. A computer network system comprising:

a plurality of computers including a computer to be monitored, which has operating system storage means for storing data used to operate the computer itself, write monitor means for monitoring that the data stored in said operating system storage means is replaced by writing update data that corresponds to the data that is stored, and read monitor means for monitoring that the data is read from said operating system storage means;

update data storage means for storing the update data in the case where said write monitor means detects that a data updating process is to be performed;

update log storage means for storing history information of the update data in the case where the update data is stored in said update data storage means; and

a line for interconnecting said plurality of the computers, said update data storage means, and said update log storage means;

wherein said read monitor means reads the update data from said update data storage means in the case where the history information for the update data is stored in said update log storage means and reads non-updated data from said operating system storage means in the case where the history information for the update data is not stored in said update log storage means, when executing data that is read out from said operating system storage means; and

wherein any one of said plurality of the computers includes repair means for;

discarding the contents stored in said update data storage means and said update log storage means in response to a first instruction, if any, to restore said operating system storage means to its initial status,

discarding the history information, which is stored in the update log storage means, after a designated arbitrary time point and the update data, which is stored in said update data storage means, in response to a second instruction, if any, to restore said operating system storage means to its initial status at the designated arbitrary time point, and

replacing the non-updated data stored in said operating system storage means with the update data stored in said update data storage means and discarding the contents stored in said update data storage means and said update log storage means in response to a third instruction, if any, to update said operating system storage means.

9. A computer network system comprising:

a first storage medium;

a second storage medium;

a third storage medium;

a plurality of computers including a computer to be monitored; and

a line for interconnecting said first storage medium, said second storage medium, said third storage medium, and said plurality of the computers;

wherein said computer to be monitored includes a first controller capable of performing the following operations;

(i) storing data used to operate said computer itself in said first storage medium;

(ii) monitoring that the data stored in said first storage medium is replaced by writing update data therein;

(iii) storing in said second storage medium updated data replaced by the update data included in the data stored in said first storage medium upon detection that the update data is written in said first storage medium; and

(iv) storing history information of the updated data in said third storage medium in the case where the updated data is stored in said second storage medium;

wherein any one of said plurality of the computers includes a second controller capable of performing the following operations;

(v) replacing the update data stored in said first storage medium with the updated data stored in said second storage medium and discarding the updated data stored in said second storage medium and the history information stored in said third storage medium in response to a first instruction, to restore said first storage medium to its initial status;

(vi) replacing the update data stored in said first storage medium with the updated data stored in said second storage medium after a designated arbitrary time point in accordance with the history information stored in said third storage medium and discarding the history information, which is stored in the third storage medium, after the designated arbitrary time point and the corresponding updated data, which is stored in said second storage medium, in response to a second instruction, to restore said first storage medium to its initial status at the designated arbitrary time point; and

(vii) discarding the updated data stored in said second storage medium and the history information stored in said third storage medium in response to a third instruction, to update said first storage medium.

10. A computer network system comprising:

a plurality of computers including a computer to be monitored, the computer to be monitored having operating system storage means for storing data used to operate the computer itself, and write monitor means for monitoring that the data stored in said operating system storage means is replaced by writing update data that corresponds to the data that is stored therein;

updated data storage means for storing updated data which is included in the data stored in said operating system storage means and replaced by the update data in the case where said write monitor means detects that the update data is written;

updated log storage means for storing history information of the updated data in the—

case where the updated data is stored in said updated data storage means; and

a line for interconnecting said plurality of the computers, said updated data storage means and said updated log storage means;

wherein any one of said plurality of the computers includes repair means for;

replacing the update data stored in said operating system storage means with the updated data stored in said updated data storage means and discarding the contents stored in said updated data storage means and said updated log storage means in response to a first instruction, if any, to restore said operating system storage means to its initial status,

replacing the update data stored in said operating system storage means with the updated data stored after a designated arbitrary time point stored in said updated data storage means in accordance with the history information stored in said updated log storage means and discarding the history information, which is stored in the updated log storage means, after the designated arbitrary time point and the corresponding updated data, which is stored in said updated data storage means, in response to a second instruction, if any, to restore said operating system storage means to its initial status at the designated arbitrary time point, and

discarding the contents stored in said updated data storage means and said updated log storage means in response to a third instruction, if any, to update said operating system storage means.

11. A recording medium having computer readable program code for operating a computer storing data used to operate said computer itself, said computer readable program code comprising:

means for causing said computer to monitor that the stored data is replaced by writing update data that corresponds to the data that is stored;

means for causing said computer to store the update data upon detection that a data updating process is to be performed;

means for causing said computer to store history information of the update data in the case where the update data is stored;

means for causing said computer to monitor that the stored data is read;

means for causing said computer to read the update data in the case where the history information for the update data is stored when reading the stored data;

means for causing said computer to read non-updated data in the case where the corresponding history information for the data to be read is not stored when reading the stored data;

means for causing said computer to discard the stored update data and the stored history information in response to a first instruction, to restore an initial status of the stored data;

means for causing said computer to discard the history information included in the stored history information after a designated arbitrary time point and the stored update data in response to a second instruction, to restore the initial status of the stored data at the designated arbitrary time point; and

means for causing said computer to replace the non-updated data with the stored update data and discard the stored update data and the stored history information in response to a third instruction, to update the stored data.

12. A recording medium having computer readable program code for operating a computer storing data used to operate said computer itself, said computer readable program code comprising:

means for causing said computer to monitor that the stored data is replaced by writing update data that corresponds to the data that is stored;

means for causing said computer to store updated data which is included in the stored data and replaced by the update data in the case where it is detected that the update data is written;

means for causing said computer to store history information of the updated data in the case where the updated data is stored;

means for causing said computer to replace the update data with the stored updated data and discard the stored updated data and the stored history information in response to a first instruction, to restore an initial status of the stored data;

means for causing said computer to replace the update data with the updated data stored after a designated arbitrary time point in accordance with the stored history information and discard the updated data stored after the designated arbitrary time point and the stored history information in response to a second instruction, to restore the initial status of the stored data at the designated arbitrary time point; and

means for causing said computer to discard the stored updated data and the stored history information in response to a third instruction, to update the stored data.