1. A database copying system for making a copy of a database, the database copying system comprising:
a first computer comprising:
a mirroring unit to, when data is written on a plurality of local disks individually, write duplicate data of the data on remote disks in a same sequence as the data was written, the remote disks corresponding to the plurality of local disks, respectively;
a current disk manager to select a first local disk out of the plurality of local disks as a current disk, and when stored data of the current disk reaches a maximum data capacity, switch the current disk to another local disk;
a data writing unit to write the data on the current disk when a data writing request arrives;
an operation information manager to, when the stored data of the current disk reaches the maximum data capacity, store first operation information in a second local disk selected out of the plurality of local disks, the first operation information requesting to update the copy of the database; and
an operation information receiver to receive second operation information indicating completion of updating the copy of the database,
wherein the current disk manager forbids the first local disk from being reselected as the current disk from the time when the current disk is switched to the other local disk to the time when the second operation information is received, and allows the first local disk to be reselected as the current disk after the second operation information is received; and
a second computer comprising:
a database update unit to, when the first operation information is copied from the second local disk to a second remote disk corresponding to the second local disk, update the copy of the database based on the duplicate data stored in a first remote disk corresponding to the first local disk; and
a transmitter to transmit the second operation information to the first computer after updating the copy of the database is completed.
2. The database copying system according to claim 1, the first computer further comprising:
an update unit to execute an update process of the database when an update request specifying a way for updating the database arrives and
output the data writing request of an update log for the executed update process.
3. A database copying method for, when data is written on a plurality of local disks individually, writing duplicate data of the data on remote disks in a same sequence as the data was written, the plurality of local disks provided in a first computer, the remote disks provided in a second computer to correspond to the plurality of local disks, respectively, the method comprising:
selecting a first local disk out of the plurality of local disks as a current disk;
writing the data on the current disk when a data writing request is received;
switching the current disk to another local disk when stored data of the current disk having the data written thereon reaches a maximum data capacity;
storing first operation information in a second local disk selected out of the plurality of local disks when the stored data of the current disk having the data written thereon reaches the maximum data capacity, the first operation information requesting to update a copy of a database provided in the second computer;
updating, when the first operation information is copied from the second local disk to a second remote disk corresponding to the second local disk, the copy of the database based on the duplicate data stored in a first remote disk corresponding to the first local disk;
transmitting, from the second computer to the first computer, second operation information indicating completion of updating the copy of the database after updating of the copy of the database is completed; and
receiving the second operation information transmitted from the remote computer, wherein:
the first local disk is forbidden from being reselected as the current disk from the time when the current disk is switched to the other local disk to the time when the second operation information is received; and
the first local disk is allowed to be reselected as the current disk after the second operation information is received.
4. A database copying method for copying data from a first computer to a second computer through a network and making a copy of a database on the second computer, the method comprising:
selecting from a plurality of local disks provided in the first computer one local disk as a current disk and another local disk as an operation information storage disk, the plurality of local disks corresponding to a plurality of remote disks provided in the second computer, respectively;
writing the data on the current disk when a data writing request arrives;
copying the data from the current disk to one remote disk corresponding to the current disk through the network in a same sequence as the data was written on the current disk;
switching the current disk to some other local disk when stored data of the current disk reaches a maximum data capacity;
writing operation information on the operation information storage disk when the stored data of the current disk reaches the maximum data capacity, the operation information indicating a local disk of which the stored data reaches the maximum data capacity among the plurality of local disks;
copying, after completion of copying the stored data of the current disk to the one remote disk, the operation information from the operation information storage disk to another remote disk corresponding to the operation information storage disk through the network;
obtaining, when the operation information is copied to the other remote disk and the operation information indicates the one local disk, the data from the one remote disk corresponding to the one local disk indicated by the operation information; and
updating the copy of the database provided in the second computer based on the data obtained from the one remote disk.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of performing a trick mode on a video signal, comprising the steps of:
in response to a trick mode command, repeating a picture in a group of pictures in the video signal to form a trick mode video signal by a processor;
determining whether to impose an upper limit on said repeating step, based on a picture type of the picture being repeated, by determining if the picture being repeated is a bi-directional predictive picture; and
selectively limiting the repeating step to a predetermined number of times up to a maximum number of pictures allowed in the group of pictures for a given standard only if the picture being repeated is a bi-directional predictive picture.
2. The method according to claim 1, wherein the trick mode comprises a frame advance trick mode.
3. The method according to claim 1, wherein the method further comprises the step of setting a display indicator of a subsequent adjacent picture to the repeated bi-directional predictive picture to a predetermined value limited to the maximum number of pictures allowed in the group of pictures.
4. The method according to claim 1, wherein the display indicator comprises a temporal reference field having an integer value.
5. The method according to claim 1, wherein the trick mode comprises a slide show trick mode.
6. The method according to claim 1, wherein the trick mode comprises a field advance trick mode, and wherein each field in the picture is repeatedly displayed until a subsequent field is decoded.
7. The method according to claim 1, wherein at least a portion of the trick mode video signal is decoded by a remote decoder.
8. The method according to claim 1, wherein the method further comprises the step of successively increasing a temporal reference field for each of the pictures being repeated and limiting the temporal reference field of a last picture in a group of pictures to a maximum number allowed in a group of pictures for a given standard.
9. The method according to claim 1, wherein the method further comprises the step of setting a temporal reference field of the picture being repeated to a value of a temporal reference field for the picture.
10. A method of performing a trick mode on a video signal, comprising the steps of:
in response to an advance trick mode command, repeating a bidirectional predictive picture in a group of pictures in the video signal to form a trick mode video signal by a processor, wherein the bidirectional predictive picture contains a display indicator having a display indicator value;
determining whether to impose an upper limit on said repeating step, based on a picture type of the picture being repeated, by determining if the picture being repeated is a bi-directional predictive picture
selectively limiting the repeating step to a predetermined number of times up to a maximum number of pictures allowed in the group of pictures for a given standard only if the picture being repeated is a bidirectional predictive picture; and
setting the display indicator of the repeated bidirectional predictive picture to the display indicator value.
11. The method according to claim 10, wherein at least a portion of the trick mode video signal is decoded by a remote decoder.
12. The method according to claim 10, wherein a last picture in a group of pictures of the video signal is set to the maximum number allowed in a group of pictures for a given standard.
13. The method according to claim 10, wherein the advance trick mode command comprises a frame advance trick mode command requiring a repeat of at least one bi-directional predictive frame picture.
14. The method according to claim 10, wherein the advance trick mode command comprises a field advance trick mode command requiring a repeat of at least one bi-directional predictive field picture.
15. A system for performing a trick mode on a video signal, comprising:
a controller for reading data from a storage medium and outputting the video signal; and
a processor programmed to:
receive a trick mode command;
in response to the advance trick mode command, repeat a bi-directional picture of an original bi-directional picture in a group of pictures in the video signal to form a trick mode video signal, wherein the picture contains a display indicator;
determine whether to impose an upper limit on said repeating step, based on a picture type of the picture being repeated, by determining if the picture being repeated is a bi-directional predictive picture
selectively limit the repeating of the bi-directional picture to a predetermined number of times up to a maximum number of pictures allowed in the group of pictures for a given standard only if the picture being repeated is a bidirectional predictive picture; and
set the display indicator of the repeated picture in the trick mode video signal to a value for the original bi-directional picture.
16. The system according to claim 15, wherein the processor is further programmed to set the display indicator of a subsequent picture of the video signal to the maximum value allowed for a group of pictures for a given standard.
17. The system according to claim 15, wherein the trick mode comprises an advance trick mode.
18. The system according to claim 15, wherein the picture to be repeated comprises a bidirectional predictive picture.
19. The system according to claim 15, wherein the display indicator comprises a temporal reference field having an integer value.
20. The system according to claim 16, wherein the advance trick mode is selected from the group of modes comprising a frame advance trick mode, a frame 3 slide show trick mode, a field advance trick mode and a field slide show trick mode.
21. The system according to claim 15, wherein at least a portion of the trick mode video signal is decoded by a remote decoder.
22. A system for performing a trick mode on a video signal, comprising:
a controller for reading data from a storage medium and outputting the video signal; and
a processor programmed to:
receive an advance trick mode command;
in response to the advance trick mode command, repeat a picture in a group of pictures in the video signal to form a trick mode video signal, wherein the picture contains a display indicator;
determine whether to impose an upper limit on a number of times the picture is repeated, based on a picture type of the picture, by determining if the picture is a bi-directional predictive picture; and
selectively limit the number of times the picture is repeated to a predetermined number of times up to a maximum number of pictures allowed in the group of pictures for a given standard only if the picture is a bi-directional predictive picture.
23. The system according to claim 22, further comprising a remote decoder for decoding at least a portion of the trick mode video signal.