JPH0277955A - Input/output controller - Google Patents

Abstract

PURPOSE:To attain the report of the sense data with the start of a command at the next execution of a job by turning on an active switch even in a sense byte holding state after the occurrence of a fault. CONSTITUTION:When a READY switch is turned on, a READY state production part 4 reads the state of the READY switch and turns on a READY flag to give an instruction for lighting a READY lamp. If a command is received from a host device 1 under such conditions, a state byte production part 5 and a state byte report part 6 work. Then the channel end and the device end of a state byte are reported as long as the READY flag is kept ON. Hereafter the part 4 turns off the READY flag when a STOP switch is turned on. At the same time, an instruction is produced to turn off the READY lamp. When an error occurs while an input/output controller 2 is kept in a stop state, a sense byte is produced and a sense byte holding flag is turned on.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an input/output control device, and is particularly suitable for a failure recovery method after completion of input/output operations with a host device.

[Conventional technology]

Conventional equipment uses SenseByte for unit checks, as described in the manual for the HITACH-8538-C1 disk controller (published by Hitachi, Ltd., January 1980, document No. 8080-2-075). It is possible to report to the host device any number of times as long as the information is constantly present.

In the state where sense information is held, unless a sense command is issued from the higher-level device, that sense information will be withheld and will be in the ready state (hereinafter referred to as READY).
It is called a state. ) [Problem to be solved by the invention] A failure during input/output operation with a host device creates a sense byte and reports a device abnormality at the start or end of a command operation. In the READY state, an input/output control device that executes an operation has a means of reporting a failure to a higher-level system. However, printer control devices have the following problems. The printer is brought to a halt state by an operator's operation, and even in the halt state, operations such as outputting data on a buffer inside the printer control device onto paper or sending paper to a stacker are executed.

If the print data is damaged due to a paper jam or the like during operation in such a stopped state and it is necessary to print the optical job again, the device must be turned off once to notify the host device of the occurrence of the failure. Must be in READY state.

However, in the conventional device, the failure is reset by turning on the switch that puts the device in the READY state.

Since it was in the READY state, there was no way to report the error to the higher-level device. Therefore, in some conventional devices, in order to prevent the above, by turning on the READY state switch, the host device is notified of N0TREADY to RE.
There was also a device that reported the device end of ADY, restarted the device from the higher level device, and then reported the unit check of the pending sense byte. However, this method still has the following problems. In the case where the machine is stopped while an input/output operation is being performed as described above, even if the device abnormality can be reported to the higher-level device, the print data may be lost due to a paper jam etc. when the machine is stopped after the job is finished and the paper is being sent to the stacker. In the case where the machine is damaged, the command activation from the host device is not received, so the sense byte of the device abnormality remains pending, and even if the READY state switch is turned on, the READY state cannot be set unless the next job is executed. Therefore, there was a problem in which the operator was unable to operate the switch or the error appeared to have not been cleared even though the cause of the error had been cleared.

An object of the present invention is to make it possible to report the suspended sense byte to the host device without resetting it once it is in the READY state.

[Means to solve the problem]

The above purpose is achieved by providing a means for setting the READY state by turning on a switch for setting the READY state, and a means for creating and reporting a unit check status byte for new activation from the host device. .

[Effect]

The input/output control device according to the present invention uses a means to enter the READY state even when a sense byte is pending.
state. On the other hand, in response to a new command activation from a host device, a unit check of pending sense data is reported by means of creating and reporting a status byte.

As described above, the subsequent operations of the host device and the input/output device operate according to the input/output operation sequence of a general information processing device. In other words, the input/output device enters the N0TREADY state when the unit check is created, and by turning on the switch for setting the device to the READY state, reports an asynchronous device end report to the host device. The host device issues the command again, and the command is executed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. It consists of a host device 1 and an input/output control device 2, and the input/output operations between the devices are common operations of information processing devices and will be omitted.

The input/output control device 2 stores a microprogram therein and has a microprocessor and memory. READY status creation unit 4° status byte creation unit 5. Status byte report section 6
is a processing group of microprograms that run on the above microprocessor. READY state operation and display section 3
is READYX first, 5TOP switch.

Turn on the READY lamp. The operation is shown below.

By turning on the READY switch, the READY state generation unit 4 reads the state of the switch and
Turn on flag. Then, an instruction is given to turn on the READY lamp. If a command is issued from the host device 1 in this state, the status byte creation unit 5. The status byte reporting unit 6 operates.

If the READY flag is on, the channel end and device end of the status byte are reported. After that, 5TOP
When the switch is turned on, the READY state creation section 4
Turn off the ADY flag.

Then, it instructs the READY lamp to turn off.

When the input/output control device 2 is in a stopped state and the READY flag is off, 9 For example, in a kanji printer control device, a paper feeding operation is performed, but if an error such as a jam occurs, a sense byte is created and the sense byte is Turn on the pending flag. This operation is executed by another processing group within the microprogram within the input/output control device 2. The above operation is the same as that of the conventional device. When the READY switch is turned on in the above state, the READY flag is turned on even if the sense byte pending flag is on. And the READY lamp is lit. When a command is activated from the host device 1, the status byte creation unit 5 sets a unit check in the status byte if the sense byte pending flag is on, and the status byte reporting unit 6 inputs and outputs the status byte to report it to the host device 1. Perform actions and report.

At the same time, the status byte generator 5 turns off the READY flag and turns off the READY lamp via the READY status generator 4. When a unit check is reported, a sense command is issued from the higher level device 1, the status byte creation unit 5 turns off the sense byte pending flag, sets the channel end and device end in the status byte, and the status byte reporting unit 6 sends a sense command to the higher level device. 1 will be reported.

The flow of the above operation is shown in FIG. FIG. 3 shows the operation of the kanji printer control device and the input/output operation with the host device according to the embodiment. FIG. 3 also shows an operational comparison with a conventional device.

〔Effect of the invention〕

According to the present invention, even if the sense byte is pending due to a failure other than the input/output operation with the host device, if the cause of the failure is cleared by turning on the operable switch, the lamp remains operational. , until a command is issued from the higher-level device while the sense byte is pending, as in conventional devices.

By not making it possible to operate, it does not appear to be inoperable to the operator.

In addition, in order to prevent an inoperable state in some conventional devices, the ready state lamp is turned on by turning on the ready switch even while the sense bite is pending.

The pending sense data was cleared and could not be reported to the host device, but according to the present invention, the sense data can be reported by starting the command at the next execution of the jib.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an input/output control device and a host device according to an embodiment of the present invention, Fig. 2 is a flowchart of processing of the module group in Fig. 1, and Fig. 3 is an operation of a host device and an input/output control device. It is a diagram comparing the conventional operation and the operation of the present invention. 1... Input/output control device, 2... Upper device.

Claims (1)

[Claims] 1. Equipped with a means for creating and reporting a status byte to the host device, a switch for transitioning to an operational state, and a means for turning on the above switch to enable the operation, and turning on the above switch while the sense byte is pending. The input/output device is characterized in that the unit is brought into an operational state by the means for making it into an operational state, and on the other hand, when activated from a host device, the unit check is reported by the means for creating and reporting the status byte. Control device.