JPH06342407A - Channel device - Google Patents

Abstract

PURPOSE:To continuously perform access from a host device to the same low order device after bus reset. CONSTITUTION:A channel device 2 connected through a bus 4 to plural low order devices 3-1-3-n, which enable access by turning to a ready state corresponding to a ready request, so as to perform access to the host devices 3-1-3-n corresponding to a request from a host device 1 is provided with a storage means 21 for storing data showing whether the plural slave devices 3-1-3-n are turned to the ready state or not, command executing means 23 for executing the command due to the host device 1, managing means 22 for reflecting the storage means 21 with changes in the ready states of the slave devices 3-1-3-n due to the operation of this command executing means 23, and bus lock control means 24 for performing the monitor of the lock state of the bus 4, lock cancel and recovery processing concerning the ready state of the plural slave devices 3-1-3-n based on the data of the storage means 21 after this lock cancel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of lower devices, such as an optical disk device and a magneto-optical disk device, which can be accessed by entering a ready state in response to a ready request. It relates to a channel device.

[0002]

2. Description of the Related Art A rewritable or write-once type optical disk device has a feature that media can be exchanged. In order to enable exchange of this medium, it is necessary to execute a ready release command as a process after use (after access). As shown in FIG. 7 and FIG. 8, the optical disk device 3 uses the ready request command (START UNI
When the ready state is changed to the ready state (READY) according to T), access becomes possible, and the ready release command (S
Not Ready (NOTR) according to TOP UNIT
EADY) and access is disabled.

When a plurality of such optical disk devices are connected to a channel device to form a system having a plurality of drives, START UNIT is transmitted for each drive (optical disk device) desired to be accessed, and STOP UNIT is sent after the access is completed. Must be sent to complete the operation. Here, if the bus line is locked due to some cause on the drive side during operation of an optical disk device and it becomes inoperable, generally the bus is reset by the host side or the device side (actually, the operator turns on the bus power supply). It often recovers from the failure by sending the operation such as dropping.).

[0004]

However, even if the bus line is restored, the bus reset (BUS RESE
As a result of T), as shown in FIG. 8, the ready state of the optical disk device 3 which has been in the ready state until now is released, and the state changes to the not ready state. For this reason,
When using the same drive thereafter, START UNI
It is necessary to send T again from the host side, and even if a bus reset is simply executed, the same drive cannot be continuously used.

The present invention has been made to solve the problems of the conventional channel device, and an object thereof is to enable an upper device to continuously access the lower device after a bus reset. It is to provide a channel device.

[0006]

Therefore, in the present invention, a plurality of lower-level devices that can be accessed by entering a ready state in response to a ready request are connected via a bus and a request from a higher-level device is received. In response to the channel device accessing the lower device, storage means for storing data as to whether or not the plurality of lower devices are ready, command executing means for executing a command by the upper device, and the command Management means for reflecting in the storage means a change in the ready state of the lower device due to the operation by the execution means, monitoring of the lock state of the bus and unlocking, and after releasing the lock, based on the data in the storage means A channel device including bus lock control means for performing recovery processing regarding the ready state of the plurality of lower devices. Configuration was.

That is, in the present invention, the monitoring / release means for monitoring the lock state of the bus by the firmware and releasing the lock state when the lock state is detected,
Bus lock control including a device state restoration unit that performs restoration processing regarding the ready states of the plurality of lower devices based on the data in the storage unit when the bus lock state is released by the monitoring / release unit Constitutes a means.

Further, according to the present invention, the bus lock condition is monitored, and when the lock condition is detected, the monitor / notification means for notifying the host device and the bus reset command are issued in response to the notification by the monitor / notification means. When it is sent from the host device, the lock release means for releasing the lock state of the bus, and the release of the bus lock state by the lock release means, based on the data of the storage means, A bus lock control unit is provided that includes a device state restoration unit that performs restoration processing regarding the ready states of the plurality of lower devices.

[0009]

According to the above construction, in the bus lock control means of the channel device, the monitoring / releasing means monitors the locked state of the bus, and when the locked state is detected, the locked state is released. That is, the bus lock is unlocked at the channel device, eliminating the need for operator intervention.
Further, the device status recovery means performs recovery processing regarding the ready status of the plurality of lower-level devices based on the data in the storage means when the bus lock status is released by the monitoring / release means. On the other hand, in the storage means, the management means reflects the change in the ready state of the lower-level device due to the operation by the command executing means, and stores data as to whether or not the plurality of lower-level devices are in the ready state. Therefore, the ready states of the plurality of lower devices are returned to before the bus lock, and the upper device can continuously access the same.

Further, the monitoring / notifying means monitors the lock state of the bus, and when it detects the lock state, it notifies the host device, so that the host device detects the bus lock. The host device sends a bus reset command to control the channel device so as to release the locked state of the bus. The device status recovery means receives the bus reset command and performs recovery processing regarding the ready status of the plurality of lower devices based on the data in the storage means. On the other hand, in the storage means, the management means reflects the change in the ready state of the lower-level device due to the operation by the command executing means, and stores data as to whether or not the plurality of lower-level devices are in the ready state. Therefore, the ready states of the plurality of lower devices are returned to before the bus lock, and the upper device can continuously access the same.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a channel device of the present invention will be described below with reference to the accompanying drawings. In each drawing, the same constituent elements are designated by the same reference numerals, and duplicate description will be omitted. FIG. 1 shows the configuration of a channel device according to an embodiment of the present invention. The channel device 2 is connected to a host device 1 including a host CPU and the like, and is also connected via a bus 4 to a plurality of lower device optical disk devices 3-1 to 3-n. The channel device 2 is provided with a command execution means 23 for accessing the required optical disk devices 3-1 to 3-n and reading and writing data according to the command from the host device 1. Optical disc device 3-1 to 3-1
3-n is a rewritable type or a write-once type, and has a configuration in which access is made possible by entering a ready state in response to a ready request, as in the optical disc device 3 shown in FIGS. 7 and 8.

The channel device 2 has a storage means 21 (flag), and each of the optical disk devices 3-1 to 3-n (No1).
~ Non), data indicating whether or not the device is in the ready state is stored. The storage means 21 is managed by the management means 22 and is operated by the command executing means 23 to operate the optical disk devices 3-1 to 3-1.
Changes in the 3-n ready state are reflected. That is, the desired optical disk devices 3-1 to 3 from the host device 1
Ready request command (ST
ART UNIT), Ready release command (STOP
In accordance with (UNIT), the management means 22 sets and resets the corresponding area of the storage means 21.

The channel device 2 has a bus lock control means 2
4 is provided. The bus lock control means 24 monitors the locked state of the bus 4, and when the locked state is detected, the monitoring / release means 26 that releases the locked state, and the monitoring / release means 26 releases the locked state of the bus. When performed, the apparatus state restoration means 25 is provided for performing restoration processing regarding the ready states of the plurality of optical disc apparatuses 3-1 to 3-n based on the data of the storage means 21. The bus lock control means 24, management means 22, and command execution means 23 are composed of firmware.
The processing operation by this firmware is shown by the flowcharts of FIGS. 2 to 3, and the operation will be described below with reference to this flowchart.

The channel device 2 starts up when the power is turned on, and initializes flags, registers and the like (30,
31). Next, it waits for a request from the higher-level device 1 (3
2), when there is a request, check the content of the request,
When it is detected that the command is the START UNIT command, a predetermined drive state flag (corresponding area of the storage means 21) is set (33, 34).
In the case of the STOP UNIT command, the corresponding drive status flag is reset (35, 36). Thus, the channel device 1 knows the state of the drive.

START UNIT command, STOP
In the processing of a normal command such as an access to a desired optical disk device 3-1 to 3-n when it is not a UNIT command (37), it is detected whether the command is executed normally (38). . If the command is executed normally, perform normal completion processing (3
9) Return to wait for a request from the higher-level device 1. On the other hand, when the command is not executed normally, the cause is analyzed and it is determined whether it is a time-out error (40). If not timed out, the corresponding error completion process is executed (44). If the time is out, the bus 4 is judged to be in the bus lock state and the bus 4 is reset (41). For example, the channel device 2 controls the power supply of the bus 4, and the power supply is temporarily cut off when the bus is reset. Next, the state of the drive is checked by the data (flag state) of the storage means 21 (42), and the START UNIT command is sent to the required drive (43).
As a result, as shown in FIG. 7, this drive (optical disk device) is in the ready state and can be continuously accessed. So in this case,
The host device 1 can request access to the optical disk device without knowing the bus lock.

In the above embodiment, the host device 1 can request access to the optical disk device without knowing the bus lock. However, when the host device 1 is configured to know the bus lock in terms of system management. 4 adopts the configuration of FIG. The bus lock control means 24A of the channel device 2A monitors the lock state of the bus 4 and notifies the host device 1 of a notice when the lock state is detected, and a notification by the monitor / notification means 28. Accordingly, when the bus reset command is sent from the host device 1, the unlocking means 27 for unlocking the locked state of the bus 4 and the unlocked state of the bus 4 by the unlocking means 27 are released. In addition, the device state restoration means 25 for performing restoration processing regarding the ready states of the plurality of optical disc devices 3-1 to 3-n based on the data in the storage means 21.
The difference from the embodiment of FIG. The bus lock control means 24A is also composed of firmware. The processing operation by this firmware is shown by the flowcharts of FIGS. 5 to 6, and the operation will be described below with reference to this flowchart.

The channel device 2 starts up when the power is turned on, and initializes flags, registers and the like (30,
31). Next, it waits for a request from the higher-level device 1 (3
2), when there is a request, check the content of the request,
When it is detected that the command is the START UNIT command, a predetermined drive state flag (corresponding area of the storage means 21) is set (33, 34).
In the case of the STOP UNIT command, the corresponding drive status flag is reset (35, 36). Thus, the channel device 1 knows the state of the drive. Up to this point, the process is similar to that of the embodiment shown in FIG.

START UNIT command, STOP
If it is neither a UNIT command, it is detected whether a reset & start command is sent from the host device 1 (51), and if it is not a reset & start command, the desired optical disk device 3-1 to 3-n Processing of a normal command such as access to
2). In this process, it is judged whether or not there is a time-out error (53). If there is no time-out error and the command is processed normally, normal completion processing is performed (55) and the process returns to waiting for a request from the higher-level device 1.
On the other hand, if the time is out, it is determined that the bus is locked and the bus lock is notified to the host device 1 (54).

Upon receiving the notification of the bus lock, the host device 1 performs processing such as creating a history if necessary,
At the same time, a reset & start command will be sent. The channel device 2 that has received this reset & start command branches to "yes" in step 51, and the bus 4 is reset (56).
For example, the channel device 2 controls the power supply of the bus 4, and the power supply is temporarily cut off when the bus is reset. Next, the state of the drive is checked by the data (flag state) of the storage means 21 (57), and the START UNIT command is sent to the necessary drive (5).
8). As a result, as shown in FIG. 7, this drive (optical disk device) is in the ready state and can be continuously accessed. In other words, in this case, the host device 1 can continuously request access to the optical disk device by knowing the bus lock and sending a reset & start command.

[0020]

As described above, according to the present invention,
When the bus becomes locked, the bus is reset, the locked state is released, and the necessary lower-level device is returned to the original ready state, so the upper-level device continuously accesses the lower-level device after the bus is reset. There is an effect that can be done.

Further, according to the present invention, the host device is notified of the bus reset, and the channel device receives the command of the host device and resets the bus line to restore the necessary ready device to the original ready state. After the reset, there is an effect that the subordinate device can be continuously accessed. In this case, the higher-level device is involved in the bus reset, and the system management and the like can be accurately executed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a channel device of the present invention.

FIG. 2 is a flowchart showing the operation of an embodiment of the channel device of the present invention.

FIG. 3 is a flowchart showing the operation of the embodiment of the channel device of the present invention.

FIG. 4 is a block diagram of another embodiment of the channel device of the present invention.

FIG. 5 is a flowchart showing the operation of another embodiment of the channel device of the present invention.

FIG. 6 is a flowchart showing the operation of another embodiment of the channel device of the present invention.

FIG. 7 is a diagram showing a state transition of the optical disc device.

FIG. 8 is a diagram showing a state transition of the optical disc device.

[Explanation of symbols]

1 Upper device 2, 2A
Channel device 3-1 to 3-n Optical disc device 4 Bus 21 Storage means 22 Management means 23 Command execution means 24, 24
A bus lock control means 25 device state recovery means 26 monitoring / release means 27 lock release means 28 monitoring / notification means

Claims (3)

[Claims] 1. A channel that is connected to a plurality of lower-level devices that can be accessed by entering a ready state in response to a ready request via a bus and that accesses the lower-level device in response to a request from a higher-level device. In the device, a storage unit that stores data as to whether or not the plurality of lower devices are in a ready state, a command execution unit that executes a command by the upper device, and a lower device ready by an operation by the command execution unit. Management means for reflecting a change of state in the storage means, monitoring and unlocking the lock status of the bus, and after releasing the lock, based on the data in the storage means, the ready status of the plurality of lower devices. And a bus lock control means for performing a recovery process regarding the channel device. 2. The bus lock control means monitors the lock state of the bus, and when the lock state is detected, the monitor / release means releases the lock state, and the monitor / release means releases the lock state of the bus. 2. The channel device according to claim 1, further comprising: a device state restoration unit that performs restoration processing regarding the ready states of the plurality of lower devices based on the data in the storage unit when the above-mentioned is performed. 3. The bus lock control means monitors the locked state of the bus, and notifies the host device when the locked state is detected, and a bus reset in response to the notification by the monitoring / notification means. When a command is sent from the host device, the lock release means for releasing the lock state of the bus, and the data in the storage means when the lock state of the bus is released by the lock release means 2. The channel device according to claim 1, further comprising a device state restoration unit that performs restoration processing regarding the ready states of the plurality of lower devices based on the above.