A method for implementing software hot-backup of main and reserve machines

The on-line/off-line software hot back-up method includes the following steps: a. for the off-line board in normal operation to send mass back-up request to the on-line boar; b. for the on-line board receiving the request to perform the mass back-up including TCP protocol datan of the off-line board; c. to enter real-time data back-up state, to judge whether to have change in the datan including TCP protocol datan of the on-line board, and if yes, for the on-line board to send real-time back-up message to the off-line board and go to step d., or if no, go to step e.; d. for the on-line board to transmit the changed data to the off-line board after the off-line receives the message; e. to judge whether the on-line board is in normal running, and if yes, to back to step c., or if no, go to step f.; and f. to change over between the on-line board and the off-line board before to enter the normal operation state. The present invention can ensure smooth communication.