JPH0498645A - Magnetic tape moving mechanism control system - Google Patents

Abstract

PURPOSE:To improve the reliability of a system by providing a spare signal line for transmitting a switching command signal besides a channel for transmitting a moving command signal between a host device and the two systems of controllers. CONSTITUTION:When a response signal can not be received from a controller 21 through a channel 11n, a host device 1n judges the fault of the device 21 and transmits the switching command signal through the signal line 11n to the controller 21 so as to command switching from the device 21 under use to a controller 22. In the case of a fault of the signal line 11n, however, any response is not enabled even to the switching command, and the device 21 still occupies a moving mechanism 31 through a signal line 201. Then, the host device 1n transmits the switching command signal through a spare signal line 13n for transmitting the switching command signal. When the switching command signal is received, the device 21 reports switching to the device 22 through signal lines 131-13n to host devices 11-1n.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic tape transfer mechanism control method, and in particular, the present invention relates to a magnetic tape transfer mechanism control method, and in particular, a transfer mechanism that transfers tape media between a magnetic tape storage and a magnetic tape device by commands of a host device. The present invention relates to a magnetic tape transfer mechanism control method that is controlled by two systems of control devices, one for use and one for backup.

[Conventional technology]

FIG. 2 is a block diagram showing a conventional magnetic tape medium transfer mechanism control system. The transfer mechanism control device has two systems, an active system control device 41 and a standby system control device 42, and transmits commands to operate the transfer mechanism 31 sent from the host devices 11 to 1n through channels 111 to lln. and 121 to 12n, and controls the transfer mechanism via the control line 20.
1 or 202 to transfer magnetic tape media between a magnetic tape storage and a magnetic tape device.

When the transfer mechanism 31 completes the transfer process according to the command,
The transfer mechanism control devices 41 and 42 terminate the command by the host device 11.
~ Report to 1n. Normally, the active control device 41 operates, but if the active control device 41 breaks down, the backup control device 42 is switched to control the transfer mechanism 31.

Now, the operation when switching from the control device 41 to the control device fi42 will be explained. Now, even though the higher-level device 1n has sent a command to the control device 41 via the channel Ion, when there is no response from the control device 41, the higher-level device 1n
n is a control device! 41 is determined to be a failure, and sends an instruction to the control device 41 to switch to the control device 42. After receiving the instruction, the control device 41 executes all the commands currently being executed, and then reports the switching to the control device 42 to all the higher-level devices 11 to 1n. During this time, even if a command is received from another higher-level device, the higher-level device is notified that the execution is refused, and the command is temporarily suspended. The host devices 11 to 1n that have received the report of switching from the control device 41 to the control device 42 send subsequent commands to the control device 42 via the channels 121 to 12n.

[Problem to be solved by the invention]

In the conventional magnetic tape transport mechanism control method, channels 111 to 1 between the control device in use and the host devices 11 to 1n
If a failure occurs in the ln, they will be unable to communicate with each other, and the higher-level device will not be able to instruct the control device in use to switch to the other control device that is on standby. system becomes impossible and the reliability of the system cannot be ensured.

The purpose of the present invention is to switch to the other control device that is on standby even if a failure occurs in the channel between the host device and the control device in use and communication between the host device and the control device in use becomes impossible. An object of the present invention is to provide a magnetic tape transport mechanism control method that can improve system reliability.

[Means to solve the problem]

The magnetic tape medium transfer mechanism control system of the present invention is a magnetic tape medium in which a transfer mechanism for transferring a tape medium between a magnetic tape storage and a magnetic tape device is controlled by two control devices in accordance with commands from a host device. In the transfer mechanism control system, a channel for transmitting a transfer command signal sent from the higher-level device to the two control devices and a response signal sent from the two control devices to the higher-level device;
and a signal line for transmitting a switching command signal sent from the higher-level device to the two control devices, and the higher-level device is configured to detect a fault in one of the two control devices in use. When this occurrence is detected, the switching command signal is sent to the one control device via the signal line to instruct switching to the other control device that is on standby.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. A channel 11 is provided between the host devices 11 to 1n and the two systems of control devices 21 and 22, the active system and the standby system, for transmitting signals etc. for commanding the transfer operation of the magnetic tape medium.
1 to 11n and 121 to 12n are provided, and in parallel thereto, spare signal lines 131 to 13n and 141 to 14n are provided for transmitting switching command signals. Now, when the higher-level device 1n has sent a transfer command to the control device F21 via the channel 11n but cannot receive a response signal from the control device 21 via the channel lln, the higher-level device 1n sends a transfer command to the control device F21 via the channel 11n. 21 has been determined to be a failure and the control device is in use! 21 to the standby control device 22 is sent to the signal line 11.
It is sent to the control device 21 via n. However, signal line 1
In the case of a failure on 1n or a failure in the entry portion thereof, it becomes impossible to respond even to the switching command, and the control device 21 remains in possession of the transfer mechanism 31 via the signal line 201. Therefore, the host device 1n sends out a switching command signal via a spare signal line 13n for transmitting the switching command signal. When the control device 21 receives the switching command signal, it executes all the transfer commands that are currently being executed, and then reports the switching to the control device 22 to all the higher-level devices 11 to 1n via the communication lines 131 to 13n. Even if a transfer command is received from another higher-level device during that time, a response is sent to the higher-level device to the effect that the execution is refused, and the transfer command is temporarily put on hold. After the host device 1n receives the switching response from the control device 21,
An instruction to start the operation is given to the control device 22 via the channel 12n. When the control device 22 becomes operational, it reports to all the host devices 'l 11 '' 1 n that it has become operational. The host device 1 n sends subsequent transfer commands via channels 121 to 12 n When the other higher-level devices receive a report of switching to the control device 22 from the control device 21 and a report from the control device 22 that the operation is possible, the other higher-level devices put the switch on hold for - hours. The maintenance personnel then sends the previous transfer command and subsequent transfer commands to the control device 22 via channels 121 to 12n. If this is carried out, the control device 21 will be in a standby state.

〔Effect of the invention〕

As explained above, according to the present invention, in addition to the channel for transmitting the transfer command signal between the host device and the two control devices, a spare signal line for transmitting the switching command signal is provided. Even if a channel failure occurs and communication between the host device and the control device in use becomes impossible, the switch command is sent from the host device to the control device in use via the signal line for transmitting the switch command signal. Since the transfer mechanism can be controlled by transmitting a signal and switching to the other standby control device, the reliability of the system can be improved.

FIG. 2 is a block diagram showing a conventional magnetic tape transport mechanism control system.

11-1n... Host device, 21.41... Active system control device, 22.44... Backup system control device, 31.
...transport mechanism, 111-lln...active channel, 121-12n standby channel, 131-13n...
. . . Working system signal lines, 141 to 14n . . . Protection system signal lines, 201, 202 . . . Control lines.

Claims (1)

[Claims] In a magnetic tape transfer mechanism control method in which a transfer mechanism for transferring a tape medium between a magnetic tape storage and a magnetic tape device is controlled by two systems of control devices according to commands from a host device, the two systems are controlled from the host device to the two systems. a channel for transmitting a transfer command signal to be sent to the control device of the controller and a response signal to be sent from the two systems of control devices to the host device, and a switching command signal to be sent from the host device to the two systems of control devices. and a signal line for transmission, and when the host device detects that a failure has occurred in one of the control devices in use among the two control devices, the host device transmits the switching command signal to the signal line. A magnetic tape transfer mechanism control method, characterized in that a command is sent to the one control device via the magnetic tape transfer mechanism to issue a command to switch to the other standby control device.