JPH021035A - Write control system for external storage device - Google Patents

Abstract

PURPOSE:To easily restore interrupted information by using second prescribed information to compensate for a part of first information on demand by an external storage controller and an external storage device at the time of interrupting the write operation of first information from a central processing unit to the external storage device by the reset operation of the central processing unit. CONSTITUTION:A central processing unit 1 issues a command to indicate write or read, and a microprocessor 3e of a semiconductor file controller 3 analyzes the command to indicate the data volume and the transfer direction to channel and device interface parts 3b and 3c. The storage address in a semiconductor memory 2a and the write or read operation are indicated to an interface circuit part 2b of a semiconductor file device 2 through the interface part 3c. When these indications are terminated, data transfer is started through a data buffer 3a, and data is transferred by the number of transfer bytes commanded to interface parts 3b and 3c.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to write control technology for external storage devices, and in particular, when a data recording area whose write operation has been interrupted by a reset command from a host device is later accessed. Concerning techniques that are effective when applied to avoid data failures that occur in other countries.

[Conventional technology]

For example, regarding techniques for avoiding data failure in external storage devices such as magnetic disk devices connected to central processing units,
A technique disclosed in Japanese Patent No. 189460 is known.

In other words, the former technology prevents the occurrence of data failure due to access to the defective area by identifying in advance a defective area that has permanently occurred in a part of the storage medium and allocating a replacement storage area near the defective area. This is what I am trying to do.

In addition, with the latter technology, when a single external storage device is used with a mixture of information with different attributes such as normal data and programs, it is possible to provide each with attribute information and refer to the attribute information during writing operations. , which attempts to prevent data failures caused by erroneously writing information with different attributes.

[Problem to be solved by the invention]

However, in any of the above-mentioned conventional techniques, if the write operation is forcibly interrupted by a reset7) command from the host device and the data being written is recorded in an incomplete state with management information etc. missing, No consideration is given to data failures such as inability to read or write data when later accessing this incompletely recorded data.

In particular, in so-called semiconductor file devices that use semiconductor memory and have a recording format equivalent to that of magnetic disks, etc., there are usually no alternative tracks, so if such a data failure occurs, the upper central processing unit There is a problem in that it is inevitable that the processing in the process ends abnormally.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a write control technique for an external storage device that can prevent data failures caused by interruption of information write operations due to reset operations of a central processing unit. Another object of the present invention is to provide a write control technique for an external storage device that can easily restore first information whose write operation has been interrupted.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

That is, an information processing system consisting of a central processing unit, an external storage device equipped with a volatile or nonvolatile storage medium, and an external storage control device that controls the exchange of information between the central processing unit and the external storage device. When the writing operation of the first information from the central processing unit to the external storage device is interrupted by a reset operation by the central processing unit,
The external storage control device and the external storage device supplement part of the first information during a write operation with predetermined second information as needed, and write the first information in a predetermined unit independently of the central processing unit.
The information writing operation is completed.

[Effect]

According to the above-described means, when the write operation is interrupted, the first information being written is not recorded in the external storage device in an incomplete state in which, for example, management information etc. are missing, and the first information is later recorded in the external storage device. It is possible to prevent the occurrence of data failures such as inability to perform read or write operations when accessing information.

Furthermore, when the central processing unit first accesses the external storage device after the reset operation, the existence of the first information is notified to the central processing unit as third information together with the position information of the first information. 1st by processing device
information can be easily restored.

〔Example〕

FIG. 1 is a flowchart illustrating an example of the operation of a write control method for an external storage device that is an embodiment of the present invention, and FIG. FIG. 1 is a block diagram illustrating an example of an information processing system in which the method is implemented.

In this embodiment, a case will be described in which a semiconductor file device using a semiconductor memory as a storage medium is used as an external storage device.

A semiconductor file control device 3 (external storage control device) is interposed between a central processing unit 1 such as a general-purpose computer and a semiconductor file device 2 (external storage device).
It is configured to control writing and reading operations for and from the semiconductor file device 2 of information exchanged between the central processing unit 1 and the semiconductor file device 2.

The semiconductor file control device 3 temporarily stores data sent from the central processing unit 1 to be stored in the semiconductor file device 2 and data read from the semiconductor file device 2 and sent to the central processing unit 1. A data buffer 3a is provided.

A channel interface unit 3b is provided between the data buffer 3a and the external central processing unit 1, and data is transferred between the data buffer 3a and a channel device (not shown) provided on the side of the central processing unit 1. It controls the giving and receiving of.

Similarly, a device interface section 3C is provided between the data buffer 3a and the semiconductor file device 2,
The configuration is such that data transfer between the data buffer 3a and the semiconductor file device 2 is controlled.

The channel interface section 3b and the device interface section 3c are collectively controlled by a microprocessor 3e that operates based on a microprogram stored in a control memory 3d.

The semiconductor file device 2 is provided with a semiconductor memo U 2 a (storage medium) and an interface circuit section 2 b that controls data exchange between the external semiconductor file control device 3 and the semiconductor memo IJ 2 a. There is.

In this case, the semiconductor file device 2 stores a magnetic disk that is a storage medium of a conventional magnetic disk device.
2a, and has a software interface similar to that of a magnetic disk drive.

That is, FIG. 3 compares an example of a track format when recording a variable length record by the so-called count key data method in the case of a magnetic disk device and the case of the semiconductor file device 2 of this embodiment. As shown in the same figure, the track format of the semiconductor file device 2 is equivalent to the track format of a magnetic disk device. There are no gaps, and each field is stored left-justified.

Furthermore, a management table T is provided at the beginning of the track in which position information of a plurality of records R8-R within the track is recorded, and the surplus area within the track is collected into one after the last record number. It forms a gap G.

Note that the home address field HA is an area in which, for example, the physical position (cylinder number, head number), status, error correction code, etc. of the track in the storage medium are recorded.

The count field C constituting the plurality of records R0 to R7 contains information on the position of the record in the storage medium, such as the cylinder number, head number, and record number, as well as information on the subsequently recorded key field and data field D. The length etc. are recorded.

In the key field, indicator information and an error correction code, etc. of the data field D to be recorded subsequently are written, and in addition, in the data field D, normal data, an error correction code, etc. are written.

The operation of this embodiment will be explained below.

First, the normal data exchange operation between the central processing unit 1 and the semiconductor file device 2 will be explained.

When a command instructing writing or reading is issued from the central processing unit 1, the semiconductor file control device 3
The microprocessor 3e analyzes the command and informs the channel interface section 3b and device interface section 3c of the amount of data (number of bytes to be transferred) and the transfer direction (in the case of a write operation, the direction from the central processing unit 1 to the semiconductor file device 2). In the case of a read operation, it instructs the direction from the semiconductor file device !ii'2 to the central processing unit 1), and also sends an instruction to the interface circuit section 2b of the semiconductor file device 2 via the device interface section 3C. , instructs a storage address and a write or read operation in the semiconductor memory 2a.

When these instructions are completed, data transfer via the data buffer 3a is started, and when the number of transfer bytes instructed to the channel interface section 3b and device interface section 3C has been transferred, the central processing unit 1 Command processing ends.

Writing and reading data to and from the semiconductor memory 2a in the semiconductor file device 2 is performed by referring to the management table T located at the beginning of the track shown in FIG.

For example, count field C, key field,
In a format write operation in which the entire data field D is written, the storage position (address in the semiconductor memory 2a) of the record immediately before the record to be written is read from the management table T, and the target record is written next to that record.

After writing the target record, the position of the record is registered by writing it in the management table T.

On the other hand, to read a record, the management table T is searched using the identification number of the target record, the position information of the record that is equal to or closest to the identification number is grasped, and the record at that position is read.

Next, when data is transferred from the central processing unit 1 to the semiconductor file device 2, that is, the semiconductor file device 2
An example of a processing procedure when a reset is commanded from the central processing unit 1 during a data writing operation will be described with reference to FIGS. 1 and 2.

In addition, in FIG. 1, for convenience of illustration, the home address field HA and the count field C are shown.

The key field and data field D are each H
They are abbreviated as A field, C field, field, and D field.

Data from the central processing unit 1 to the semiconductor file device 2 via the semiconductor file control device 3 (first information)
When a reset is commanded from the central processing unit 1 during the write operation (step 100), the transfer of data from the central processing unit 1 to the semiconductor file control device 3 and the semiconductor file device 2 is interrupted.

At this time, the channel interface section 3b of the semiconductor file control device 3, triggered by the reset command, supplements the untransferred data from the central processing bag W1 with predetermined pseudo data (second information) and sends it to the data buffer 3a.

In this way, after a reset command is issued from the central processing unit 1, the write operation for one field of the record being written is performed independently of the central processing unit 1 by the hardware of the semiconductor file control device 3 and the semiconductor file device 2. is executed (step 110).

When the write operation for one field is completed, a reset command is issued to the microprocessor 3e, and the execution address of the microprocessor 3e is changed to a specific address of the microprogram in the control memory 3d set in advance. Then, the microprocessor 3e starts operating from the specific address of the microprogram.

First, in the control memo 'J3d, the central processing unit 1
Since the command that was being executed at the time when the reset command was received from is stored, read it out. It is determined whether the command is a format writing command that involves rewriting (step 120).

If a format write command is being executed, it is checked whether the field in which writing was interrupted is the home address field HA (step 130).

If the field in which writing was interrupted is not the home address field HA, the write position of the record for which the write operation has been completed is written in the management table T at the beginning of the track independently of the central processing unit 1 (step 1).
40).

Next, it is determined whether the field for which writing was interrupted is count field C (step 150).

If the field for which writing was interrupted is count field C, the length of the key field in the count field C is checked (step 160), and if the length of the key field is not 0, that is, key field K exists. In this case, pseudo data corresponding to the length of the key field is used as a key field and the semiconductor memory
a (step 170).

Further, if the length of the key field is 0, that is, if the key field K does not exist, the process of step 170 is skipped.

Next, the length of data field D is determined from count field C, and pseudo data (second information) corresponding to the length of data field D is written as data field D into the semiconductor memo IJ 2 a (step 180).

On the other hand, if it is determined in step 150 that the field for which writing was interrupted is not count field C, it is further determined whether or not it is key field K (step 190), and if writing is in progress in the key field. , step 180 is similarly performed.

Further, in the step 130, if it is determined that the field whose writing has been interrupted is the home address field HA, the record R0 in the management table T
In step 200 for deleting subsequent registrations, all records of the track to which the home address field HA belongs are erased.

Next, a sense byte (third
information) is created (step 210).

This sense byte contains, for example, the polycomb number, cylinder number, head number, etc. that identifies the semiconductor file device 2 that was in the process of writing when the reset command was issued from the central processing bag [1] from other external storage devices. Includes numbers, etc.

Note that the sense byte creation process in step 210 is determined to be not a format write command in step 120, and further in step 220, only the 0 part of the data field is rewritten without changing management information etc. It is also executed when it is determined that an update write command is being executed.

After the reset command is issued, when the host central processing unit 1 issues the first command to the semiconductor file device 2, the semiconductor file control device 3 performs a unit check to report the hardware status of the semiconductor file device 2. Following the information, the sense byte is sent to the central processing unit l.
Send to.

The central processing unit 1 that has received the sense byte performs appropriate recovery processing on the data (first information) stored inside the semiconductor file device 2 specified by the sense byte, and then Normal data exchange between the processing device 1 and the semiconductor file device 2 is started.

In this way, according to this embodiment, the semiconductor file device 2
Even if a write operation is forcibly interrupted by a reset command from the higher-level central processing unit 1, the information such as the record being written may be stored in an incomplete state with, for example, management information missing. do not have.

For this reason, for example, when the central processing unit l accesses a record stored in an incomplete state in the semiconductor file device 2, writing or reading operations become impossible, and the execution of a program using the data becomes abnormal. Data failures such as data termination are prevented from occurring.

Furthermore, the sense byte notifies the central processing unit 1 of the existence and location of records that may contain errors whose write operations have been forcibly interrupted by a reset command from the host central processing unit 1. The central processing unit 1 can easily perform repair processing on information such as records.

In the above embodiment, the case where the count key data method is adopted as the recording format in the semiconductor memory 2a has been described, but the present invention is not limited to this, and any recording format may be used. .

Further, the external storage device is not limited to a semiconductor file device using a semiconductor memory as a storage medium, but any other storage medium may be used.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

In other words, information consisting of a central processing unit, an external storage device including a volatile or nonvolatile storage medium, and an external storage control device that controls the exchange of information between the central processing unit and the external storage device. In the processing system,
When the write operation of the first information from the central processing unit to the external storage device is interrupted due to a reset operation by the central processing unit, the external storage control device and the external storage device may perform the write operation as necessary. Part of the first information is supplemented with predetermined second information, and the write operation of the first information in a predetermined unit is completed independently of the central processing unit, so that the write operation is interrupted. The first information being written when the first information is written is not recorded in the external storage device in an incomplete state with, for example, management information missing, and when the first information is accessed later, read or write operations are It is possible to prevent the occurrence of data failures that would make it impossible.

Furthermore, when the central processing unit first accesses the external storage device after the reset operation, the existence of the first information is notified to the central processing unit as third information together with the position information of the first information. 1st by processing device
information can be easily restored.

[Brief explanation of the drawing]

FIG. 1 is a flowchart illustrating the operation of a write control method for an external storage device that is an embodiment of the present invention, and FIG. 1 is a block diagram showing an example of an information processing system. 1...Central processing unit, 2...Semiconductor file device (
external storage device), 2a...semiconductor memory, 2b...
Interface circuit unit, 3... Semiconductor file control unit (external storage control device), 3a... Data buffer, 3b... Channel interface unit, 3C...
Device interface section, 3d...Control memory, 3e...Microprocessor, T...Management full, HA...Home address field, C.
...Count field, K...Key field, D
...Data field, Ro-R-...Record, G, ~G,, G...Gap. Agent Patent Attorney Yamato Kanai Procedural Amendment (Method) The statement ``-Browak diagram illustrating an example.'' on page 2, line 5 of the statement of contents of the amendment is amended as follows. l. Incident display: ``Example plotter diagram, Figure 3 of Patent Application No. 36575 of 1988 is an explanatory diagram showing an example of the storage format of 2° invention name data in a semiconductor file device.'' External storage device Name related to the case of the person who corrects the writing control method (510)

Claims (1)

[Scope of Claims] 1. A central processing unit, an external storage device including a volatile or nonvolatile storage medium, and an external storage that controls the exchange of information between the central processing unit and the external storage device. and a control device, when a write operation of first information from the central processing unit to the external storage device is interrupted by a reset operation by the central processing unit, the external storage control device and the external storage device supplements a part of the first information during the write operation with predetermined second information as necessary, and completes the write operation of the first information in a predetermined unit independently of the central processing unit. A write control method for an external storage device, characterized in that: 2. The external storage control device detects the existence of the first information when the central processing unit first accesses the external storage device after the reset operation.
2. The write control system for an external storage device according to claim 1, wherein said central processing unit is notified of said information together with a storage location of said information as third information. 3. The write control method for an external storage device according to claim 1, wherein the storage medium is a semiconductor memory in which the information is stored in a recording format equivalent to a magnetic disk.