JPS59112353A - Data reading out system from recording medium - Google Patents

Abstract

PURPOSE:To reread data from another recording medium in duplicated recording media having individual address in each recording medium by managing an error detected at the reading out of data by a medium controlling device. CONSTITUTION:If an error detection processing part 202 detects an error during the reading out of data from a master desk 121 by a reading command, a command to stop the reading is outputted to a reading mechanism 113. An error processing program 102 analyses the error, and when the error is recoverable, rereading is commanded to a desk controlling device 110. Consequently, a command processing part 201 sets up a reading command to a register 203 corresponding to a sub-desk 122 and commands reading from the sub-desk 122 to the mechanism 113. Thus, data are reread from another correct recording medium, so that the load of a control program is reduced and other controlling functions can be completed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a reading method for a disk or the like in an information processing apparatus, and more particularly to a data reading method in a system in which recording media are duplicated.

[Prior art]

For example, with the spread of large-capacity solid-state media disks, duplication of disks is required as a countermeasure in the event of a failure. Conventionally, the method for reading data on 2m disks has been to use individual disks for each disk.
The address is set to 2, and the control program of the processing device is set to 2.
If a read command is issued by specifying the address of one of the duplicated disks, and an error occurs during the read,
The control program specified the other address of the duplicated disk, reissued a read command, and reread the data. In this way, conventionally, the control program of the processing device itself manages the individual addresses of the duplicated disks and issues a reread command for error recovery when a read error occurs. This not only increases the burden on the control program of the processing device, but also
This has the disadvantage that the memory area for storing the control program also increases. Incidentally, the same can be said when duplicating other recording media such as drums and tapes.

[Purpose of the invention]

An object of the present invention is to prevent the control program of a processing device from being aware of the individual addresses of the duplicated recording medium when an error is detected during data reading (by reissuing the same read command). The object of the present invention is to provide a method for rereading data from another recording medium.

[Summary of the Invention] In order to achieve the above object, the present invention allows a medium control device to manage a pair of duplicated recording media each having an individual address. Then, in response to a read command from the control program of the processing device, the medium control device reads data from one of the predetermined recording media, and if an error occurs during reading, the control program is instructed to read the data again. Report an error and request a retry. Upon receiving this report, the control program of the processing device reissues the same read command as before.

That is, it instructs to retry the read command. In response to this reissued read command, the medium control device selects another recording medium in which no error has occurred and reads data. The present invention will be described in detail below, taking as an example a data reading method in a disk control device with dual disks.

[Embodiments of the invention]

FIG. 1 shows one embodiment of the present invention, showing an entire computer system including a processing device 100, a disk control device 110, a disk drive device 120, a display device 130, and the like.

The processing device 100 contains a control program 101 and a processing program 103 that control the entire electronic computer system. The control program 101 includes an error handling program 102. The disk control device 110 also includes a transfer mechanism 111, a control mechanism 112, a continuous output mechanism 113, and a write mechanism 114. The disk drive device 120 is
It has a primary disk 121 and a secondary disk 122 on which data of the same content is recorded.

FIG. 2 shows the control mechanism 11 in the disk controller 110.
FIG. 2 is a detailed diagram of No. 2. That is, the control mechanism 112 includes a command processing section 201, an error detection processing section 202, and a register group 208.
Consisting of The command processing unit 201 is in charge of processing corresponding to various commands (read commands, write commands, etc.) directed by the processing device 100, and the error detection processing unit 202 is in charge of error detection and error processing for data read from the disk. . In this embodiment, it is assumed that the processing required by the command processing section 201 and the error detection processing section 202 is executed by a microprogram. FIG. 8 is a microprogram flow diagram of the command processing section 2010 for a read command, and FIG. 4 is a microprogram flow diagram of the error detection processing section 2020. The register group 208 includes a buffer register for temporarily storing write/read data, and status registers corresponding to the primary and secondary disks that indicate the status of the disk.

When an input request to the disk is issued from the processing program 108 in the processing device 100, the control program 1 that received this request creates a channel command word (CCW) group including a read command, and sends it to the disk control device. 11
Issue an input command to 0. The procedure for issuing this input command is the same as the conventional one, so a detailed explanation will be omitted.

The disk control device 110 receives a read command transferred from the processing device 100 via the transfer mechanism 111, and causes the control mechanism 112 to execute processing corresponding to the read command. That is, in the case of a read command, the command processing unit 201 in the control mechanism 112 checks whether the error of the primary disk 121 has been set in the status register corresponding to the primary disk in the register group 208, according to the processing flow shown in FIG. Step 800) If the setting has not been completed, a read instruction is set in the status register and the read mechanism 113 is instructed to read data from the primary disk 121 (step a).
o1,804).

Bladder evacuation mechanism 118 controls disk drive 120;
Data is distributed to the designated primary disk 120.

The error detection process m202 in the control mechanism 112 inspects the data successively output from the primary disk 121 according to the process flow shown in FIG.
11 to the processing bag [100 (step 40
0,401). In this way, if no error is detected during the continuous output of data that has been transferred j times, the transfer mechanism 111
reports the normal completion of the read command to the processing device 1000 control program 101. When the continuation command is successfully completed, the control program 101 notifies the processing program 108 of the completion of the input request.

This also applies when no error is detected in data read from the secondary disk 122, which will be described later.

- If an error is detected in the read data from the primary disk 121, the error detection processing unit 202
Since the read instruction is set in the status register corresponding to the primary disk 208, the data is transferred to the primary disk 1.
21 (step 402).
), sets in the status register that an error has occurred in the primary disk 121 (resets the read instruction),
An instruction to stop the continuous output is given to the continuous output mechanism 11B (steps 408 and 404). Furthermore, processing device ii 100
create error information indicating that the error is recoverable;
The error information is transferred to the processing device 100 via the transfer mechanism 111.
0 control program 101 (step 405
, 406).

FIG. 5 shows the processing flow of the error handling program 102 within the control program 101.

That is, the error processing program 102 in the control program 101 analyzes error information according to the processing flow shown in FIG. Then, if the error is recoverable (step 500), the disk controller 11 instructs the disk controller 11 to retry the read command.
0, the display device 130 notifies the operator of the error occurrence, and records the error information in a file (steps 501 to 508).

When the command processing unit 201 of the control mechanism 112 in the disk controller [110] receives the reissue read command via the transfer mechanism 111, the command processing unit 201 executes the process according to the processing flow shown in FIG.
After confirming whether the error has occurred next to the primary disk 121 (step 800), it is checked whether the secondary disk 122 is normal using the status register corresponding to the secondary disk (step 80).
2). Here, if it is found that the secondary disk 122 is also abnormal, the command processing unit 201 creates unrecoverable error information without instructing the bladder evacuation mechanism 118 to read data from the secondary disk 122, and causes the transfer mechanism 111 to The processing bag [100 is notified through the process (steps 805 and 806).

On the other hand, if the secondary disk 122 is normal, a read instruction is set in the status register corresponding to the secondary disk, and the subsequent output mechanism 118 is instructed to read data from the secondary disk 122 (steps 808 and 804).

The data read from the secondary disk 122 is stored in the control mechanism 1.
If there is no error, the error detection processing unit 202 of TL7. ,). - If an error is detected in the retrieved data from the secondary disk 122, the error detection processing unit 202 sets the read instruction in the status register corresponding to the secondary disk in register #203, so that the data is Knowing that it is from the secondary disk 122 (step 402), it sets the relevant status register to indicate that an error has occurred and issues an instruction to the reading mechanism 113 to stop reading (steps 407 and 408). Furthermore, in this case, since both the primary and secondary disks 121 and 122 are not normal, error information indicating that the processing bag @ 100 is unrecoverable is created and notified to the processing device 1000 control program 101 via the transfer mechanism 111. (steps 409 and 406).

Upon receiving unrecoverable error information from the disk control device 110, the error processing program 102 in the control program 101 reports the error to the processing program 103 and similarly to the operator according to the processing flow shown in FIG. and record the error information to a file (step 5)
04.505.506).

Although the present invention has been described above with respect to a disk device, it goes without saying that it can be similarly applied to external storage devices such as drums and tapes.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a system configuration in which the recording medium is dual-electronic, if an error is detected one day when reading data from the recording medium, the open side that controls the entire system One program does not need to be aware of the individual addresses of the two storage media (,
By simply reissuing the same read command, it becomes possible to retrieve data from another normal storage medium.
1. The burden on wholesale programs is reduced, and each station is able to enhance other control functions.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of the configuration of an acid computer system to which the invention is based, Fig. 2 is a detailed diagram of the control mechanism in Fig. 1, and Figs. 8 to 5 are for explaining the method of the present invention. FIG. 2 is a processing flow diagram. 100... Processing device, 101... Control program,
102...Error processing program, 108...Processing program, 110...Disk control device, 111...
...Transfer 1 number, 112...Control a pattern, 11B...
Enlightening mechanism, 114... Writing mechanism, 120... Disk drive interposition, 121.122... Disk, 20
1...Command Building Department, 2 (J2...Niji-Detection Processing Department., Agent Makoto Suzuki (shoulder) Figure 1

Claims (2)

[Claims] (1) A processing device, a control device that controls read/write to a recording medium based on commands from the processing device, and a primary and secondary record with a duplex structure that is connected to the control device and records the same data. In an electronic computer system comprising a medium, the control device reads data from the primary recording medium in response to a read command from the processing device;
If an error is detected in the read data, a retry request is issued to the processing device, and upon receiving the retry request, H
d) The processing device reissues the same read command as before, and in response to the reissued read command, the control device selects a sub-recording medium and re-reads the data. A method for reading data from a medium. (2) When the control device detects an error while reading data from the primary recording medium, and when the sub-recording medium can be re-read, the control device reports the error indicating that re-reading is possible as a retry request to the processing device; 2. A method for reading data from a recording medium according to claim 1, wherein when it is impossible, an irrecoverable error is reported.