JPH0683752A - Composite storage device connected to host device - Google Patents

Abstract

PURPOSE:To prevent a composite storage device consisting of an HDD and a cassette streamer from being reset by a reset signal generated on the outside when the composite storage device is independently driven. CONSTITUTION:The composite storage device 3 consists of the HDD 6 and the cassette streamer 7. The device 3 is connected to a host device 1 through a 1st SCSI bus 2. The HDD 6 is connected to the streamer 7 through a 2nd SCSI bus 8. A 1st switch 12 is connected between the 1st and 2nd buses 2, 8. The 1st and 2nd buses 2, 8 are standardized by SCSI. At the time of writing data in the streamer 7 from the HDD 6, the 1st switch 12 is turned off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite storage device including a first storage device such as a hard disk device and a second storage device such as a cassette streamer.

[0002]

2. Description of the Related Art In a small computer system,
A plurality of peripheral devices (magnetic disk device, magnetic tape device, optical disk device, printer) are often connected to a host computer (host device). Generally, ANSI is used to connect multiple peripheral devices to a host device.
(American National Standards Institute) SCSI (Small Cmputer System)
Interface) is performed according to the standard. Peripheral device is S
Each device is called a CSI device, and each device has a SCSI ID or device number (address) for identifying them, and can communicate with a host device and between SCSI devices.

[0003]

By the way, in order to facilitate backup, a hard disk device (hereinafter referred to as HDD) and a magnetic tape device (hereinafter referred to as HDD) are provided.
There is a composite memory device that is a composite of the streamer). Composite storage device and additional SC for SCSI bus
When an SI device is connected, the host device communicates with another SCSI device via the SCSI bus during the backup operation of writing the HDD data of the composite storage device to the streamer or the restore operation of writing the streamer data to the HDD. The host device suspends the operation of all the SCSI devices when it is in the state and is in a reset condition for some reason. As a result, H
Data transmission between the DD and the streamer is also interrupted, which may cause data destruction.

Therefore, it is an object of the present invention to operate from the first storage device to the second storage device without being affected by other peripheral equipment connected to the host device or affecting other peripheral equipment. It is to provide a composite memory device capable of transferring data to a computer.

[0005]

The present invention for achieving the above object is a composite memory device connected to a host device via a first bus conforming to a predetermined interface standard, and communicating with the host device. A first storage device capable of performing communication, a second storage device capable of communicating with the host device and also capable of communicating with the first storage device, the first storage device and the second storage device. Second memory device connected to each other and formed to enable communication in accordance with substantially the same standard as the first bus.
Bus, a connection terminal for connecting to the first bus, a switch provided between the connection terminal and the second bus, and the first or second storage device in the host device. And a control means for controlling the switch to be turned on when connecting the switch and controlling the switch to be turned off when the first and second storage devices communicate with each other.

[0006]

The second bus in the composite memory device is used for communication (data transfer) between the first and second memory devices, and the second bus in the composite memory device and the host device and the first and second memory devices. It is also used for intercommunication with storage devices. The switch is used to disconnect the second bus from the first bus. When the first and second storage devices communicate with each other, the second storage device
Since the bus of is separated from the first bus by the switch,
The second bus is unaffected by the first bus. Therefore, even if a reset condition occurs on the first bus side when the switch is turned off, the first and second storage devices can continue mutual communication without interrupting the operation. Further, since the switch is turned off when the first and second storage devices are communicating with each other, the composite storage device does not occupy the first bus.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a composite memory device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a small computer system. This computer system includes a host computer (host computer) 1 and a composite storage device 3 and an HDD 4 via a first bus 2 of the SCSI standard.
Are connected by a digi-chain. Termination resistors 4 and 5 are connected to the first bus 2. Although the first bus 2 is shown by one line for simplification of the drawing, it is actually made up of eighteen consisting of nine data signal lines and nine control signal lines. .

The composite storage device 3 has an HDD 6 as a first storage device and a cassette streamer 7 as a second storage device. The HDD 6 and the streamer 7 are connected to each other by a second bus 8 complying with the SCSI standard.
This second bus 8 also has termination resistors 9, 10. A second switch 12 and a bidirectional buffer 13 are connected between an input terminal 11 for connecting to the first bus 2 and the second bus 8. It should be noted that the input terminal 11, the first switch 12, and the buffer 13 are of course provided in plural (18). Further, the host device 1, the HDD 4, the HDD 6, and the streamer 7 each include an interface conforming to the SCSI standard, that is, a bus driver circuit and a receiver circuit.

A CPU for controlling the composite storage device 3
A (central processing unit) 14, an operation button 15, and a second switch 16 are provided. The operation button 15 is the CPU 1
4 is connected to the CPU 4, and various commands are sent to the CPU 14 by this operation. The CPU 14 controls ON / OFF of the first and second switches 12 and 16 and gives a command to the HDD 6 and the streamer 7. The second switch 16 is CP
U14 is selectively connected to the second bus 8.

As shown in FIG. 2, the bidirectional buffer 13 has first and second buffers 21 and 22 connected in antiparallel, and a bus monitor 23 connects the first and second buffers 21 and 2 to each other.
2 is configured to be on / off controlled. The bus monitor 23 is a signal line 24 on the initiator side (host device 1 side) and a target side (HDD, streamer side) signal line 2
5 is connected to. The signal line 24 is a BUS as a signal indicating that the initiator side device requests acquisition of the right to use the bus or a signal indicating that the bus is in use.
The Y signal is provided. The signal line 25 is supplied with a BUSY signal as a signal indicating a request for acquisition of the bus use right from the target side device or a signal indicating that the bus is in use. The bus monitor 23 is a BUSY signal line 24.
It is determined which of the signal and the BUSY signal of the signal line 25 has occurred earlier, and the first or second buffer 21 or 22 corresponding to the earlier signal is controlled to the ON state. For example, when a low-level BUSY signal is first generated on the initiator-side signal line 24 as shown in FIG.
In response to this, generates a low level switch control signal as shown in FIG. 3 (B), and activates the first buffer 21. If the BUSY signals are generated at the initiator side and the target side at exactly the same time, the buffer 21,
It is configured to operate by giving priority to only one of the two.

H of the host device 1 and the composite memory device 3, for example
During communication with the DD 6, the first switch 12 is turned on and the second switch 16 is turned off based on the operation of the operation button 15. Since the HDD 6 has a SCSI ID (address), the host device 1 can use this address to specify the HDD 6 for communication. Communication between the host device 1 and the streamer 7 is also performed by the same method.

When writing the data in the HDD 6 to the streamer 7, the first switch 12 is operated by operating the operation button 15.
Is turned off and the second switch 16 is turned on. CPU
A command signal 14 for writing data from the HDD 6 to the streamer 7 is sent to the second switch 16 and the second bus 8.
The data is given to the HDD 6 and the streamer 7 via the to write predetermined data. As a result, the data in the HDD 6 can be backed up by the streamer 7. A similar method is used when transferring the data of the streamer 7 to the HDD 6. The first switch 12 disconnects the composite storage device 3 from the first bus 2 when transferring data only inside the composite storage device 3. Therefore,
The host device 1 and the first bus 2 can be used without being restricted by the composite memory device 3. Further, even if the host device 1 or the HDD 4 is in a reset condition and a signal indicating reset is generated, the composite memory device 3 can continue the operation regardless of the reset condition signal.

[0013]

MODIFICATION The present invention is not limited to the above-mentioned embodiments, and the following modifications are possible. (1) The composite storage device 3 is not limited to the combination of the HDD 6 and the streamer 7, but the combination of the HDD and the magneto-optical disk device, the combination of the HDD and the HDD, the HDD
And a floppy disk device can be combined. (2) It is applicable not only to the SCSI standard but also to the case of using another type of interface. (3) First using a switch instead of the buffer 13
The bus 2 and the second bus 8 may be connected or disconnected. For example, when the second bus 8 is connected to the first bus 2 without using the buffer 13, the terminating resistors 9 and 10 of the second bus 8 are disconnected by a switch.

[Brief description of drawings]

FIG. 1 is a block diagram showing a computer system according to an embodiment of the present invention.

2 is a block diagram showing a buffer of FIG. 1. FIG.

FIG. 3 is a waveform diagram showing a state of each part of FIG.

[Explanation of symbols]

 1 Host Device 2 First Bus 3 Complex Storage Device 6 HDD 7 Streamer 8 Second Bus

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[Procedure amendment]

[Submission date] July 12, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

[0003]

By the way, in order to facilitate backup, a hard disk device (hereinafter referred to as HDD) and a magnetic tape device (hereinafter referred to as HDD) are provided.
There is a composite memory device that is a composite of the streamer). HDD and streamer under the control of host device
In addition, during backup operation to write the HDD data of the composite storage device to the streamer or to streamer data to HD
During the restore operation of writing to D, for example, Li host device
When a reset condition occurs due to the set button being pressed by mistake , the host device suspends the operation of all SCSI devices. As a result, the data transmission between the HDD and the streamer is also interrupted, and it is necessary to retransmit the data.
It will be important.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

The object of the present invention is to provide a composite memory device can transfer data from the first storage device without affected by the host equipment to the second storage device.

Claims (1)

[Claims] 1. A first according to a predetermined interface standard.
A first storage device capable of communicating with the host device, the first storage device capable of communicating with the host device, and the first storage device capable of communicating with the host device.
A second storage device capable of communicating with the second storage device, the first storage device and the second storage device are connected to each other, and comply with substantially the same standard as the first bus. A second bus formed so that communication is possible; a connection terminal for connecting to the first bus; a switch provided between the connection terminal and the second bus; The switch is controlled to be turned on when the first or second storage device is connected to the host device, and the first and second storage devices are controlled.
Storage device including control means for controlling the switch to be turned off during mutual communication of the storage devices.