JPS62133548A - Retry control system in input/output control device - Google Patents

Abstract

PURPOSE:To efficiently execute a retry at high speed by calculating retry control information by a firmware, and executing the retry, based on the retry control information. CONSTITUTION:A processing for issuing an SNS command is added to a software. when an I/O control circuit 8 detects a normal or abnormal end, and applies an interruption to a central control unit 2, the software decides abnormal end or an abnormal end by reading out the contents of a device status register 4-1. When it is decided to be an abnormal end, and decided to execute a retry, the SNS command is issued. As a result, a firmware calculates retry control information by executing an arithmetic working to control information extending from a start time stored in a RAM 7 to the time of generation of an error, and applies the interruption to the central control unit 2.

Description

[Detailed Description of the Invention] (Summary) When a failure occurs in an input/output device (magnetic tape, typewriter, disk device, etc.), retry control is performed by reading control information stored in memory from the time of startup until the time of failure. By calculating the retry control information and retrying based on the retry control information, the input/output control device is able to perform the retry optimally and at high speed without increasing the negative degree of soft tone air. A retry control method is disclosed.

(Field of Industrial Application) Is the present invention a retry system in a single input/output control device? In the fl method, especially when a failure occurs in an input/output device, retry control information is calculated by firmware and the retry control 17
The present invention relates to a retry control method in an input/output control device that performs retries easily and efficiently based on visual perception.

(Prior Art) Generally, when a failure occurs in an input/output device such as a magnetic tape, a typewriter, or a disk drive, a retry is performed by software to troubleshoot the failure. Conventionally, the input/output device described above has been controlled by software as shown in FIG.

That is, in order to start up the input/output control device that controls the input/output device, the central control device sets various control data in a control register provided in the input/output control device. Note that the control register is a device status register (DSR) in which state information of the input/output control device is stored.

The file address register (FAR) stores the access address of the input/output device, and the command register stores the control information for starting/stopping the input/output control device and the information for specifying the operation contents. (CMR
), a memory address register (MAR) that stores target address information for information transfer in the main memory, and a word count register (WCR) that stores information that does not indicate the number of transferred words. .

When the above-mentioned information is set in the FAR, MAR, and WCR, and a command is set in the CMH, the microprocessor is interrupted and the program is started. Then, the microprocessor accesses the input/output device based on the contents of the control register, checks whether or not the access is performed normally based on the contents of the DSR, and then accesses the WCR. Enables data transfer of the set number of words. The program ends normally when the data transfer of the number of words ends (the contents of the WCR at this time become "0"). However, if a failure occurs during the data transfer and it is determined that a retry should be performed, various control data at the time of startup are set in the control register, and a retry is performed based on the state at that time. That is, the conventional retry control method retries the program from the beginning.

(Problems to be Solved by the Invention) In the conventional glue try control method, as described above with reference to FIG. Since the retry is performed based on the above, there is a problem in that the retry process takes a long time. The problem will be specifically explained below using an example in which the input/output device is a disk device.

Generally, a file on a disk device is divided into a plurality of sectors (as shown in FIG. 4) by index marks 16 and address marks 17L.
In the example shown in FIG. 4, ζ is 64 sectors), a plurality of tracks (10 tracks in the example shown in FIG. 4) constituted by the plurality of sectors, and a plurality of tracks constituted by the plurality of trunks. Cylinder (4th
In the illustrated example, it is composed of 67 cylinders). Access to the disk device is performed sector by sector. Therefore, access starts from sector 0 of a track in a cylinder, for example, and sector 2
Assuming a case where the access processing was performed normally until then, but an error occurred in the middle of sector 3, the retry processing due to the occurrence of the error will be performed from the sector 3 mentioned above in order to improve the efficiency of processing time. It is desirable to start. but.

In the conventional method, since retry processing is started from sector O, there is a drawback that processing time becomes redundant.

(Means for Solving the Problems) The present invention solves the above-mentioned problems, and FIG. 1 shows a flow chart of the principle of the software in the present invention.

The present invention includes firmware for efficiently retrying when an error occurs. That is,...
As shown in FIG. 1, when an error occurrence is detected and a retry is determined, a sense status command (SNS command) is issued. The relevant S
When the NS command is issued, the firmware generates retry control information based on control information from the time of startup to the time of error occurrence, which is stored in the memory 7, which will be described later in connection with the embodiment shown in FIG. Calculate FAR, MAR
, WCR. Then, the FAR, MAR, W
A retry is executed based on the retry control information set in the CR.

(Function) In the conventional retry control method, the retry control method is performed from the start of the last access to the input/output device, whereas in the present invention, the retry control method is performed based on the retry control information calculated by the firmware. This is because a new attempt is made when the above error occurs.

Retry processing time is shortened and retry can be performed efficiently.

(Example) FIG. 2 shows a configuration diagram of an embodiment of the present invention.

In the figure, numeral 1 is an input/output control device (IOc), 2 is a central control device (CC), and 3 is an input/output device.

In the illustrated example in FIG. 2, a disk unit (DKU) is shown.

In the input/output control device (rOc) 1, reference numeral 4 is a control register, and the device status register (D
SR) 4-1. Input/output device (D in the example shown in Figure 2)
A file address register (FAR) 4-2 in which access addresses of KU) are stored. A command register (C
MR) 4-3. Memory address register (MAR) 4-4, which stores the target address for information transfer in the main memory (not shown). and a word count register (WCR) 4-5 in which transfer word number information is stored.

Also, 5 is a microprocessor (μP), 6 is a ROM
, 7 is a RAM, 8 is an IO control circuit (10CTL) that controls 10 (DKU 3 shown), 9 is a program mode control circuit (PMCTL) that controls program mode transfer, 10 is an IO address verification circuit (to ■〇8), which performs verification of 10 addresses.

11 is an interrupt control circuit ([NTCTL) that controls interrupt operations; 12 is a switching circuit (SEL); 13
First-in first-out register (
14 is an IDMA mode control circuit that controls transfer in IDMA mode, and 15 is a DMA mode control circuit that controls transfer in DMA mode. Hereinafter, the glue try control method of the present invention described above with reference to FIG.
) 3 will be explained using an example of a command to transfer data.

Based on the software shown in FIG. 1 described above, the central controller (CC) 2 controls the file address registers (FAR) 4-2. Memory address register (M
AR) 4-4. and word count register (W
Control information at startup (hereinafter referred to as initial information) is set in the command register (CMR) 4-5, and the command register (CMR
) 4-3 causes an interrupt to the microprocessor (μP) 5, and the ROMG
The following processing is started based on the above firmware.

The initial information is stored in the RAM 7 by the firmware, and the central control unit (CC) 2 and 10 (
Data transfer between DKU) 3 and switching circuit (SEL) 1
2. PIFO13 and IO system? 11 circuits (IOcT
I-) via 8.

And the word count register (WCR) 4
If the content of −5 becomes “0” and the above command ends normally, or if an error occurs and the above command ends abnormally, the 10 control circuit (rOcTL) 8 detects the normal end or abnormal end. and interrupts the microprocessor (μP) 5, which in turn interrupts the central controller (CC) 2.

In response to the interrupt, the software determines whether the command has ended normally or abnormally due to the occurrence of an error by reading the contents of the device status register (DSR) 4-1. If it is determined that the process has ended abnormally, it is determined whether or not to perform a primary retry. If it is determined to retry, the S
Issue the NS command. When the SNS command is issued, the firmware calculates retry control information by processing the control information stored in the RAM 7 from the time of startup to the time of error occurrence, and sends the information to the central controller (C
C) Interrupt 2. When the interrupt occurs, the central controller (CC) 2 sets the retry control information,
A retry is executed based on the retry control information.

The above has described the connection try control method when the instant input/output device is a disk device in connection with the embodiment shown in FIG.

Needless to say, the same applies to magnetic tape devices, typewriters, etc.).

(Effects of the Invention) As explained above, according to the present invention, 1) simply by adding processing for issuing an SNS command to conventional software, 2) retry control information is calculated by firmware, and the retry control information is Since the retry is performed based on the above, the retry processing time can be shortened and the versatility of the software is not impaired. Therefore, it is possible to perform high-speed and efficient processing without unnecessary processing.

[Brief explanation of drawings]

Figure 1 shows the principle flow of the software in the present invention.
2 is a configuration diagram of an embodiment of the present invention, and FIG. 3 is a flow chart of software in a conventional system.
FIG. 4 shows an example of the file address structure of a disk unit. In the figure, 1 is an input/output control device, and 2 is a central control device. 3 is an input/output device (disk device), 4 is a control register,
4-1 is a device status register. 4-2 is a file address register, 4-3 is a command register, 4-4 is a memory address register, 4-5 is a word count register, 6 is a ROM,
7 is a RAM, 8 is a 10 control circuit, 9 is a program mode control circuit, 10 is a ■0 address verification circuit, 11 is an interrupt control circuit, 12 is a switching circuit, 13 is a first-in.
14 represents a first out register, 14 represents an I DMA mode control circuit, and 15 represents a DMA mode control circuit.

Claims (1)

[Scope of Claims] At least a control register (4) is provided in which a group of control information for controlling the input/output device (3) is stored, and the input/output device (3) is controlled based on the contents of the control register (4).
), an input/output control device (1) for controlling the control process, comprising: a memory (7) for storing the control information group that is updated in accordance with the progress of the control process prior to the control process; and an abnormal termination of the control process. At times, firmware is provided to read out the control information group from the start of the control process to the occurrence of an abnormality from the memory (7) and calculate retry control information, and perform a retry based on the retry control information. A retry control method for an input/output control device characterized by: