JPH052550A - Input/output device control system - Google Patents

Abstract

PURPOSE:To attain an extremely extensible system without restricting the number of devices to be connected to an I/O channel device in accordance with the sorts of the devices only by adding simple functions to the I/O channel device and each device to be connected to the I/O channel device. CONSTITUTION:The I/O channel device 21 is provided with a command issuing part 22, and when a power supply is turned on, issues, an attribute command to respective devices(26-0 to 26-5) corresponding to respective ID numbers ID#0 to ID#5 by means of the command issuing part 22 in order to check which devices are connected to an I/O bus 15. When device information such as the block length and device sort of each device is returned through an attribute informing part 27 in the device, the device 21 stores the returned device information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input / output device control system for an input / output channel device in a computer system.

[0002]

2. Description of the Related Art One input / output channel device (channel)
A computer system in which several types of input / output devices (hereinafter referred to as devices) are connected to each other is generally configured as shown in FIG.

In the system of FIG. 3, reference numeral 11 denotes an input / output channel device, which is a control center of the system.
A main memory 13 that provides storage areas for various data and programs and the like are interconnected via a system bus 14.

The I / O channel device 11 has a SCSI (Sm
Various devices 16-0 to 16-5 are connected via an input / output bus 15 typified by an all Computer System Interface) bus. The devices 16-0 to 16-5 have different ID numbers (identifiers).

In the various devices 16-0 to 16-5 connected to the input / output bus 15, the length of a block (1 block) which is a designated unit of transfer amount, that is, the block length is not necessarily the same. Also, the commands used by the I / O channel device 11 for the devices 16-0 to 16-5 are not necessarily common, and are specific to the device type (such as seek command for hard disk device and optical disk device,
There is a rewind command in the tape device).

Therefore, when the input / output channel device 11 accesses the device 16-i for controlling data transfer between the main memory 13 and the device 16-i (i is any of 0 to 5). Must know the block length and device type of the device 16-i, that is, the attribute (device information) of the device 16-i. If the device information is not known, an error occurs such that the count number for data transfer is incorrect, or an unsupported command is sent to the device.

Therefore, conventionally, a method of fixing the ID number and the type of the device 16-i connected to the input / output bus 15 as shown in FIG. 3 has been applied. That is, for example, IDs # 0 to # 3
(Device 16-0 to 16-3) is a hard disk device, ID
# 4 (device 16-4) is an optical disk device, and ID # 5
(Device 16-5) was designed in advance like a tape (magnetic tape) device.

In this system, since the device type is fixedly determined by the ID number, the input / output channel device 11
The device information can be stored in advance for each ID number (ID # 0 to # 5), and correct device access was possible.

[0009]

As described above, since the ID number and the type of device are fixed in the past,
Although the I / O channel device can have device information in advance for each ID number, there is a problem that the number of devices connectable to the I / O channel device is limited depending on the type, as described below.

That is, in the example of FIG. 3, one input / output bus 15
If you can connect only up to 6 devices to
The devices connected to the input / output bus 15 were limited to a maximum of four hard disk devices, a maximum of one optical disk device, and a maximum of one tape device, and were not expandable.

Therefore, when it is desired to connect, for example, six optical disk devices in the system as shown in FIG. 3, it is necessary to apply the following method (a) or (b). (A) A method in which six channel devices similar to the input / output channel device 11 are connected to the system bus 14 and one optical disk device is connected to each. (B) Six optical disk devices can be connected (that is, I
A method of modifying the input / output channel device 11 so that D # 0 to D5 all indicate an optical disk device.

However, in the above method (a), one input / output channel device is required for each optical disk device, so that there is a problem that the system becomes expensive. Further, in the above method (b), it is necessary to modify the input / output channel device according to the configuration of the device connected to one input / output bus, and there are dozens of configurations depending on the combination of device types. There was a problem that an I / O channel device had to be prepared.

The present invention has been made in view of the above circumstances, and an object thereof is to add an easy function to an input / output channel device and a device (input / output device) connected to the input / output channel device. It is an object of the present invention to provide an input / output device control method that does not limit the number of devices connected to the device depending on the device type, and can realize a system with high expandability.

[0014]

The present invention relates to various devices (input / output devices) in an input / output channel device which are connected to the channel device via an input / output bus and to which a unique identifier is arbitrarily assigned. On the other hand, while providing a command issuing means for issuing a specific command for recognizing the device information (attribute) of the device, in each device,
It is characterized in that attribute notifying means is provided for notifying the input / output channel device of device information of its own device in response to a specific command issued by the command issuing means.

[0015]

According to the present invention, one type of input / output bus output from the input / output channel device is connected to various types of devices to which arbitrary identifiers (ID numbers) are arbitrarily assigned. In this way, when the ID number and device type are made variable, the I / O channel device cannot know the device information such as the block length and device type of the device actually connected to the I / O bus.

Therefore, in the above configuration, a command issuing means for issuing a specific command for recognizing device information is provided in the input / output channel device, and, for example, when the power is turned on,
A specific command (attribute command) is issued for each device connected to the input / output bus, and the device information of the device is inquired. The device which receives this notifies the input / output channel device of its own device information (attribute) by the attribute notifying means provided in the device. This allows the input / output channel device to know in advance the device information (block length, device type, etc.) of various devices connected to the device (via the common input / output bus).

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same parts as those in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 is a block diagram showing the configuration of a computer system having an input / output channel device directly related to the present invention. In the figure, reference numeral 21 denotes an input / output channel device, which is a specific command for recognizing device information (attribute) of various devices connected to the input / output bus 15 such as the SCSI bus output from the same channel device 21. It has a functional block (hereinafter, referred to as a command issuing unit) 22 that issues an attribute command.

26-0 to 26-5 are devices connected to the input / output bus 15. In the present embodiment, the number of devices that can be connected to the input / output bus 15 is limited to a maximum of 6, for example,
As described later, there is no limitation by type. Also, the ID number (identifier) assigned to the device is not fixed depending on the type, but can be selected from the six types of predetermined ID numbers ID # 0 to ID # 5 (within the range where they do not overlap with each other). Can be assigned to. In the example of FIG. 1, the devices 26-0 to 26-5 have IDs as unique ID numbers.
# 0 to ID # 5 are assigned.

Each of the devices 26-0 to 26-5 is provided with a functional block (hereinafter referred to as an attribute notifying unit) which notifies the device information (block length, device type) of its own device according to the attribute command from the input / output channel device 21. 27) are provided.

Next, the operation of the configuration of FIG. 1 will be described with reference to the flowchart of FIG. I / O channel device 21
When the power is turned on, the device performs processing according to the flowchart of FIG. 2 in order to check what device is connected to the input / output bus 15.

That is, the input / output channel device 21 first initializes the ID number ID # i to ID # 0 (step S1), and thereafter, using the command issuing unit 22, uses the ID # i (= ID
An attribute command is issued to the device (# 0) (here, the device 26-0) via the input / output bus 15 (step S2).

In the attribute command addressed to (the device of) ID # i, the device 26-j (j is any of 0 to 5) to which the ID # i (here, ID # 0) is assigned exists in the system. If (if connected to the I / O bus 15) then it is received at the device 26-j. As a result, the device 26-j uses the attribute notifying unit 27 of the device 26-j to output device information describing its block length, device type, etc. via the I / O bus 15 to the I / O channel device 21.
To notify.

Now, the input / output channel device 21 uses ID # i
When an attribute command addressed to (device of) is issued, the timer is started (step S3), and ID # i
Waiting for device information notification from the device (step S
4) If the device information is notified (reset the timer), the information is internally stored in association with the ID number (ID # i) (step S5). On the other hand, the device 26-j to which ID # i is assigned does not exist in the system,
Therefore, even if a timeout is detected (step S
6) When the device information is not notified, the I / O channel device 21 internally stores that the device with the ID # i does not exist in the system (step S7).

The input / output channel device 21 uses the above step S.
When 5 or S7 is executed, the next ID number is set by ID # i ← ID # (i + 1) (step S8). Then, the I / O channel device 21 checks whether i ≦ 5 (step S9). If i ≦ 5, device information collection from devices with ID numbers up to ID # 5 is not completed. Then, the process returns to step S2, and an attribute command is issued to (the device of) the ID number after +1 to collect the above device information.

As described above, the input / output channel device 21
Repeats the device information collection by issuing the attribute command from ID # 0 to ID # 5. As a result, as shown in FIG. 1, when the maximum allowable number of devices, that is, the six devices 26-0 to 26-5 are connected to the input / output bus 15, these devices 26-0 to 26 -5 each device information is I
It is stored in the input / output channel device 21 corresponding to D # 0 to D5.

After that, the input / output channel device 21 operates in the main memory 13
12 that directs data transfer between the device and the device 26-j
The I / O command (SIO command) from the device 26-j can be received and the device 26-j can be accessed according to the device information of the device 26-j (collected when the power is turned on).

As described above, the input / output channel device 21 in this embodiment collects the ID numbers and device information of the devices 26-0 to 26-5 connected to the input / output bus 15 when the power is turned on. , Each device according to this device info 26
-Can access 0 to 26-5. Therefore, the ID
It is not necessary to fix the number and the type of device, and the I / O bus 15 (maximum number of devices connectable to) of the I / O channel device 21 can be used to the maximum.

That is, in the example of the system of FIG. 1, a device can be arbitrarily connected to the ID # 0 regardless of the type, whether it is a hard disk device, an optical disk device, or a tape device. This also applies to the other IDs # 1 to # 5.
Therefore, in the system of FIG.
It is possible to connect a maximum of 6 units in either type of optical disk device or tape device. In the conventional system shown in FIG. 3, as described above, only four hard disk devices, one optical disk device and one tape device can be connected.

[0030]

As described in detail above, according to the present invention,
From the I / O channel device, a specific command for recognizing the device information (attribute) of the device is attached to various devices that are connected to the I / O channel device via the I / O bus and are arbitrarily assigned unique identifiers. It is configured to be issued to each device and notified of device information from each device. By using this device information, it is possible to access each device correctly without fixing the ID number and device type. it can. Therefore, according to the present invention, the number of devices connected to the input / output channel device is not limited by the device type, and the system expandability is improved.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing an embodiment of a computer system including an input / output channel device to which the present invention is applied.

FIG. 2 is a flowchart for explaining the procedure of device information collection processing of the input / output channel device 21 shown in FIG.

FIG. 3 is a block diagram showing a conventional example.

[Explanation of symbols]

12 ... CPU, 13 ... Main memory, 14 ... System bus, 15 ... I / O bus, 21 ... I / O channel device, 22 ... Command issuing unit, 26-0 to 26-5 ... Device (I / O device), 27 ... Attribute notification part.

Claims (1)

Claim: What is claimed is: 1. A computer system comprising an input / output channel device for controlling data transfer between a main memory and various input / output devices, wherein the input / output channel device is changed to the same channel device. Command issuing means for issuing a specific command for recognizing the attribute of the input / output device to various input / output devices connected via the input / output bus and arbitrarily assigned unique identifiers, and this command issuing means An attribute notifying unit for notifying the input / output channel device of the self-input / output device from the input / output device receiving the specific command issued by the input / output device. By issuing the specific command by the command issuing means to each connected input / output device, the attribute of each input / output device can be obtained. Input and output device control method in which the butterflies.