JPH0250245A - Peripheral control device - Google Patents

Abstract

PURPOSE:To prevent unwritten data or uninformed status from being deleted with the unexpected interruption of a power source or the execution of diagnosis, etc., by providing the three types of storage parts for a function stopping flag, a function stop defusing flag and a device corresponding flag in a peripheral control device. CONSTITUTION:The peripheral control device is equipped with an input and output (I/O) control part 17 to a high order device, a reading and writing circuit 16 to external peripheral devices 21-24, a buffer 14 to execute the temporary store of data between the I/O control part 17 and the reading and writing circuit 16, storage parts 11-13 to store a processing condition when a function stop is indicated from the high order device to the peripheral devices 21-24, and a microprogram control part. Thus, the unwritten data in the buffer 14 are written by one time of indication from the high order device. Then, when the unwritten data are remained, the power source is prevented from being interrupted unexpectedly.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a peripheral control device, and particularly to a peripheral control device that does not lose unwritten data when its functions are stopped by a command from a host device. Regarding.

[Prior Art] In a peripheral control device having a buffer, data received in response to a write command from a host device is stored in the buffer, and when the storage of data in the buffer is completed, the write command is sent to the host device. Some report completion and write to peripherals asynchronously.

However, the unwritten data that exists in the buffer is
This is something that operators, maintenance staff, etc. cannot see directly. Therefore, in such peripheral control devices, it is often unclear whether or not unwritten data remains in the buffer, and the power cannot be carelessly turned off during maintenance or the like.

For this reason, conventional peripheral control devices prepare an instruction to write unwritten data in a buffer to a specific peripheral device, execute this instruction for all peripheral devices, and then turn off the power. .

[Problems to be Solved] The conventional peripheral control device described above has the following problems.

■Since instructions had to be executed for each peripheral device, in cases where the peripheral control device is connected to multiple independent host devices, while writing unwritten data in the buffer to the peripheral device. Then, a new write command is issued to another peripheral device, and there is a possibility that the function of the peripheral control device cannot be stopped.

01 If a peripheral control device has multiple connection paths, even if you try to execute an instruction to write unwritten data in the buffer, if that peripheral device is occupied by another path, the instruction cannot be executed and the It is not possible to stop the functions of the peripheral control device.

The present invention was made in view of the above problems, and it writes out unwritten data in the buffer with a single command from the host device, and also prevents the power from being inadvertently turned off when unwritten data remains. The purpose is to provide a peripheral control device that will not cause any problems.

[Means for Solving Problems] In order to achieve the above object, the peripheral control device of the present invention has an I/O control section that performs input/output I/O with a host device, and an I/O control section that performs read/write operations for external peripheral devices. a buffer that temporarily stores data between the I/O control unit and the read/write circuit, and a buffer that performs processing when the host device instructs the peripheral device to stop functioning. A storage unit that stores the status and the above ■/
This configuration includes a microprogram control section that controls the O control section and the read/write circuit, writes and reads the processing status into and from the storage section, and performs processing to stop the functions of peripheral devices.

[Example] Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a block diagram when a peripheral control device according to an embodiment of the present invention is applied to a magnetic tape control device.

In the figure, l is the entire peripheral control device, 11 is a function stop instruction flag, 12 is a function stop refusal flag, and 13 is a device correspondence flag. Further, 14 is a buffer, 15 is a microprogram control section, 16 is a read/write circuit, and 17 is an I/O control section. Further, 21 to 24 are peripheral devices.

Further, FIG. 2 is a flowchart showing an outline of processing in the peripheral control device of FIG. 1, and hereinafter, the operation of the peripheral control device of FIG. 1 will be explained according to the flow of FIG. 2.

First, the peripheral control device 1 is in a state of waiting for an input/output request from the host device (301), and upon detecting an input/output request from the host device, determines whether the sent command is a function stop command (302). If the instruction is not to stop the function, execute the operation specified by the instruction such as writing/reading data (
303) L/ is waiting for a new input/output request. Note that in the case of a data write command, when the storage of data in the buffer 14 is completed, the end of the command is reported to the host device, and then the data is written to the peripheral device asynchronously.

On the other hand, if the command sent from the host device is an instruction to stop the function, the function stop instruction flag 11 is set to ° l'',
Set function stop refusal flag 12 to '0' device compatible flag 1
All 3's are 11? (304). Further, from now on, all input/output requests sent from the host device to the I/O control unit 17 are ignored until the series of processing described below is completed. Then, the following checks are sequentially performed on all connected peripheral devices 21-14.

■Check if there is unwritten data in the buffer 14 (
305), if there is unwritten data, writing to the peripheral device is executed (306).

(2) If writing fails, 'l' is set in the function stop refusal flag 12 (307-30B).

If there is no unwritten data in the buffer, the presence or absence of unreported status is checked (3/O), and if there is unreported status, the function stop refusal flag 12 is set to +1' (308).

(3) If neither red write data nor unreported status exists, the bit for the peripheral device in the device correspondence flag 13 is reset (311).

■Sequentially performing the above checks, check whether the function stop refusal flag is set to ``l'' (312). If it is 19, report the rejection of the function stop instruction to the host device (3
09).

(3) If the function stop refusal flag 12 is '0', it is checked whether all the device support flags 13 are set to 90' (313).

(2) If all device correspondence flags 13 are not set to 90', the check for all peripheral devices has not yet been completed, and the check from step 305 is repeated.

■If the device support flags 13 are all +0', there is no unwritten data or unreported status inside the peripheral control device l, so it reports to the host device that it is possible to stop the function (314 ).

As described above, in this embodiment, when a command from a higher-level device instructs to stop the function of a specified peripheral control device,
A function stop instruction flag that remembers that a function stop instruction has been received, and a function stop instruction flag that remembers that a function stop instruction has been received, and a function check flag that indicates that the peripheral control device connected to the peripheral control device has no unwritten data remaining in the buffer. It has a device compatible flag that indicates that there is no effect by stopping the function, and a function stop refusal flag that indicates that the function stop instruction from the host device should be rejected if the function cannot be stopped.

When it receives an instruction to stop the function from a higher-level device, it ignores new input/output requests and stores all peripheral devices in the buffer until it reports to the higher-level device whether or not the function can be stopped. Checks whether there is any unwritten data remaining or status that has not been reported to the host device, and if unwritten data remains in the buffer, executes writing to the peripheral device. When there is no longer any unwritten data regarding the peripheral device, the device flag for the peripheral device is set to indicate that there is no effect due to the outage. If it is not possible to stop the function of a peripheral *J# device, such as when it remains in the buffer or there is an unreported status, set the function stop refusal flag and set all device support flags. When it becomes possible to stop the function, or when the function stop refusal flag is set, a function is achieved to report to the host device whether or not the function can be stopped.

[Effects of the Invention] As explained above, the present invention provides peripheral control H@ with three functions: a function stop flag, a function stop refusal flag, and a device compatible flag.
It is possible to write all the unwritten data in the buffer to the peripheral device with a single command from the host device. If data remains in the buffer or unreported status remains, unwritten data can be prevented from being accidentally turned off, diagnosed, etc. by refusing to stop the function to the host device. This has the effect of providing a peripheral RS device that can prevent loss of unreported status and other information.

[Brief explanation of the drawing]

FIG. 1 is a block diagram when a peripheral control device according to an embodiment of the present invention is applied to a magnetic tape control device, and FIG.
2 is a flowchart showing an outline of processing in the peripheral control device of FIG. 1. FIG. 15: Microprogram 1 # section 16: Read/write circuit 17: I/O control section 21 to 24: Im side FiK

Claims (1)

[Claims] An I/O control unit that performs input/output I/O with a host device, a read/write circuit that reads/writes to an external peripheral device, and a a buffer for temporarily storing data; a storage unit for storing a processing state when the peripheral device is instructed to stop functioning from the host device;
A microprogram control unit that controls the /O control unit and the read/write circuit, writes and reads the processing status to and from the storage unit, and performs processing to stop the functions of the peripheral device. Peripheral control device.