JP2748056B2 - Disk controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for controlling access to a storage unit, and more particularly to a disk controller for controlling access to a disk-shaped storage medium storing data in a sector system.

[0002]

2. Description of the Related Art In a data processing system, an external storage device is used to store a large amount of data.
The external storage device includes a disk-shaped storage medium (hereinafter, simply referred to as a disk) such as a magnetic disk or an optical disk, and stores data on the disk.

In a data processing system having an external storage unit (hereinafter, referred to as a disk unit) using a disk as a storage medium, as shown in FIG. 3, an arithmetic processing unit 100 such as a CPU (central processing unit) and a disk The disk controller 1 is provided between the disk controller 1 and the unit 200. Arithmetic processing unit 100 and disk unit 200
Is transferred via the disk controller 1. That is, the disk controller 1 accesses the disk unit 200 according to a command (command) from the arithmetic processing unit 100. At the time of data writing, write data from the arithmetic processing unit 100 is written to the disk unit 200 via the disk controller 1. At the time of data reading, the disk unit 20
From 0, data is read into the disk controller 1, and the read data is transferred from the disk controller 1 to the arithmetic processing unit 100.

FIG. 4 shows a disk controller 1 shown in FIG.
FIG. 3 is a diagram showing an example of a specific configuration of FIG. Referring to FIG.
The disk controller 1 receives a control signal group 3 from an arithmetic processing unit (not shown in FIG. 4), and a control circuit 6 for controlling the operation of the disk controller 1. And a buffer 4 for performing input / output. The control signal group 3 includes not only control signals provided from the arithmetic processing unit but also signals (ready / busy signals) output from the disk controller 1 to the arithmetic processing unit 1. Buffer 4 includes a data input buffer and a data output buffer.

The disk controller 1 further includes a status register 14 for storing status information such as an operation state of the disk controller 1, a data register 15 for storing data supplied from an arithmetic processing unit or a disk unit, and a control circuit 6. Under control, the buffer 4, the status register 14 and the data register 15
And a multiplexer 5 for controlling the connection to The multiplexer 5 connects the status register 14 to the buffer 4 when transmitting status information indicating the state of the disk controller 1 to the arithmetic processing unit. The multiplexer 5 connects the data register 15 to the buffer 4 when a command or data is given from the processing unit or when data from the disk unit is transferred to the processing unit.

The disk controller 1 further includes a command register 7 for storing parameters associated with a command given from the arithmetic processing unit, a drive interface 8 for controlling input / output of data to / from the disk unit in accordance with the given command, A serial interface control (SI control) 13 for controlling a serial interface when serially transferring data to and from a disk unit is included. Drive interface 8 connects one of input port 11 and output port 12 to internal data bus 2 in accordance with a given command (given through data register 15).

After the command is stored in the command register 7, it is decoded by a decoder (not shown). The operation of each of the interfaces 8, 13 and the like is controlled according to the decoding result. The path of this control is not shown.

[0008] The input port 11 receives data provided from a disk drive (a device for controlling actual recording / reproduction of data on a disk) included in the disk unit. The output port 12 transmits the data transmitted on the internal data bus 2 to the drive of the disk unit via the drive interface 8.

[0009] Serial interface control 1
Reference numeral 3 controls a serial interface such as establishing data transfer timing required for data transfer with the disk unit drive during the data transfer.

The control circuit 6 performs a read / write operation of this disk controller and a D
The MA (direct memory access) / INT (interrupt) operation is controlled.

A disk as a storage medium normally holds information by a method as shown in FIG. In FIG. 5, the disk 16 has a plurality of sectors SE arranged along the circumference.
including. Each sector SE is provided with a sector identifier, and a corresponding sector is accessed according to the sector identifier, and information is written to or read from the accessed sector. Such a configuration in which a plurality of sectors are provided, an identifier is assigned to each sector, and information is stored is hereinafter referred to as a “sector system”.

When a disk is used in a file management system, the file management information is not stored in one sector, but refers to a sector for storing information for storing the file content itself and the content. It is divided into two sectors for storing information. That is, the file management information includes information indicating the content of the file itself,
And information for referring to the contents of this file.

In the configuration shown in FIG. 5, reference information 19 is included in the n1st sector 17, and this reference information 19 is provided.
Indicates the state where the actual contents of the file are stored in the sector (n2th sector) designated by. Such a reference method is referred to as “indirect reference”.

The reference information 19 is stored in an area shifted from the head address of the n1st sector by an offset value offset. Hereinafter, the operation for reading the contents of the file stored in the n2th sector will be described.

In the case of reading the actual file contents from the reference information 19 stored in the n1st sector 17 according to a program, the operation according to the flowchart shown in FIG. 6 is executed. The operation of reading information from a file will be described below with reference to FIGS.

First, in order to read the sector n1 in which the reference information 19 is stored, the arithmetic processing unit sets a sector read command and a sector number n1 to be read in the disk controller 1. That is, first, the arithmetic processing unit 10
0 issues a sector read command to the disk controller 1 (step S20). This sector read command is given via the data register 15.
Next, this command is decoded by decoding means (not shown). A configuration may be used in which the control circuit 1 is controlled in accordance with the decoding result to set the disk controller 1 in the sector read mode.

Alternatively, the sector read command is expressed by a combination of states of control signals included in the control signal group 3, and the operation state of the disk controller 1 is set under the control of the control circuit 6. Is also good.

When the disk controller 1 is set to the sector read mode, this state is set in the status register 14.

When the disk controller 1 is set to the sector read operation, the arithmetic processing unit 100 then sends out a sector number n1. The disk controller 1 stores the given sector number n1 in the command register 7 (Step S21).

The command register 7 stores the sector number n1
Is transmitted to the drive of the disk unit via the drive interface 8 and the output port 12.

In the drive of the disk unit,
Data of sector n1 is read from the disk according to the given sector number n1. The data of sector n1 read from this disk is stored in disk controller 1
Is read into the memory included in the arithmetic processing unit according to the DMA transfer mode or the program transfer mode under the control of (step S22).

In the DMA transfer mode, the data read from the disk unit by the disk controller 1 is directly read into the memory in the arithmetic processing unit.
In the program transfer mode, data transferred from the disk controller 1 under the control of the processing unit is read into a memory in the processing unit.

The arithmetic processing unit then reads out the reference information 19 from the transferred and read data of the sector n1,
It is known that the sector to be referred to is the sector n2 (step S23).

When the arithmetic processing unit detects the reference information 19 in accordance with the offset value offset, the sector read command and the sector number n2 as a parameter of this command are read in the same manner as described above in order to read the file (the contents of the n2th sector) again. Is set in the disk controller 1 (steps S24 and S25).

Then, in the same manner as described above, the n-th disk
Two-sector data is read into the memory in the arithmetic processing unit via the disk controller 1 (step S2).
6). As a result, the contents of the desired file are stored in the memory.

[0026]

In the configuration of the conventional disk controller, in order to access different sectors, it is necessary to issue a command from the arithmetic processing unit and give it to the disk controller every time each sector is accessed. is there.

Even when the sector indicated by the sector reference information is a target to be finally accessed, first, a read command is issued to read the sector in which the sector reference information is stored. It is necessary to issue a read command again to read the sector indicated by the sector reference information. That is, when reading the contents of a file in accordance with "indirect reference", it is necessary to issue a read command twice, and there is a problem that it takes a long time to read the contents of a desired file.

It is therefore an object of the present invention to eliminate the above-mentioned disadvantages of the conventional disk controller and to provide a disk controller capable of reading the contents of a desired sector at a high speed.

Another object of the present invention is to provide a disk controller capable of constructing a file management system capable of reading the contents of a high-speed file.

[0030]

A disk controller according to the present invention uses a sector number and an offset value as command parameters, designates a storage location of sector reference information according to the sector number and the offset value, and refers to the sector reference. It reads sector reference information stored in an information storage location and accesses a corresponding sector in accordance with the read sector reference information. That is, the disk controller according to the present invention stores an offset value indicating a position in the sector at which the sector reference information specifying the reference sector is stored, and compares the current access position of the sector with the stored offset value. Offset detection means for detecting a match / mismatch, and sector reference information storage means using information of a predetermined size read from the sector as reference sector identification information (sector reference information) in response to a match detection signal from the offset detection means. Means for accessing a corresponding sector according to the reference information stored in the storage means.

[0031]

According to the disk controller of the present invention,
When the offset detecting means detects a match, data of a predetermined size is stored as sector reference information for specifying a reference sector from the position where the match is detected, and the corresponding sector is accessed according to the sector reference information. Therefore, the arithmetic processing unit can access a desired sector only by issuing a single command, and can access the desired sector at high speed.

[0032]

FIG. 1 is a block diagram schematically showing an entire configuration of a disk controller according to an embodiment of the present invention. 1, parts corresponding to those of the conventional disk controller shown in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.

Referring to FIG. 1, disk controller 1 of the present invention includes offset detecting section 9 for detecting that the current position in a sector coincides with an offset value from the head of a sector specified by a command parameter. And an access sector number storage unit 10 for storing, as sector reference information, data stored in a predetermined size from a position where the match is detected, in accordance with a match detection signal from the offset detection unit 9.

In the command register 7, as a parameter of the sector indirect read command, a sector number for storing the reference sector information and a position (offset value offset) in the sector where the reference sector information is stored.
Are set in the command register 7.

In the "indirect read" mode, the storage location of the sector reference information is specified by the sector number and the offset value from the head of the sector identified by the sector number, and the access to the sector indicated by the sector reference information is performed. Is executed by issuing a single command.

The "direct read" mode is a mode in which the contents of a sector specified by a sector number are all read from the head position.

FIG. 2 is a flowchart showing an indirect read operation of the disk controller according to one embodiment of the present invention. The operation of the disk controller according to one embodiment of the present invention will be described below with reference to FIGS. As the data structure of the disk, the data structure shown in FIG. 5 is assumed.

First, a sector indirect read command is issued to the disk controller 1 (step S3).
1). The sector indirect read command and the sector direct read command are different from each other, and can distinguish between the indirect read mode and the direct read mode. The setting of this command may be performed on the control circuit 6 using the control signal group 3, or a command may be set on the command register 7 via the data register 15 and stored in the command register 7. The command may be decoded by a decoder (not shown) and an operation mode may be set. At this time, the command may be stored in the data register 15 instead of the command register 7.

The multiplexer 5 connects the buffer 4 to the data register 15 according to the indirect read command. The operation of the multiplexer 5 is controlled by a control circuit 6
Run under the control of

Next, as parameters of this indirect read command, the sector number n1 and the offset value offse
t is generated by the processing unit and set in the disk controller 1. More precisely, it is set in the command register 7 via the data register 15. The offset detector 9 monitors the flow of data on the internal data bus 2 using the offset value set in the command register 7 as a reference value. This offset detector 9 is provided corresponding to the offset value storage register if the register position where the offset value is set in the command register 7 is fixed.

Then, in accordance with the read command (indirect read command), the disk controller 1 sets the sector number n set in the command register 7 as a parameter.
1 is transmitted to the disk unit via the drive interface (drive IF) 8 and the output port 12. This data transmission is executed under the control of the serial interface control 13. In the disk unit, the contents of the sector with the sector number n1 are read, and the contents of the sector number n1 are transmitted to the input port 11.

Drive interface 8 transmits data applied to input port 11 onto internal data bus 2. The offset detector 9 monitors the data supplied from the drive interface 8 and monitors the position of the data provided on the internal data bus 2 in the sector having the sector number n1.

As a method for the offset detecting section 9 to know the current position in the sector, when data is transmitted from the input port 11 in byte units, the data is transmitted in synchronization with a clock signal, and thus the clock is counted. Thus, a configuration for knowing the current position in the sector may be used.
As this clock, a clock signal for determining data input / output timing in the disk controller 1 may be used. A baud rate determination clock may also be used. Further, a synchronization signal for data transfer transmitted from the serial interface 13 may be used as a clock signal. A configuration may be used in which a timer started in response to reading of data in sector n1 is used, and the current position of the sector is known from the timer output.

Further, the offset detecting section 9 may detect the change time point of the data on the internal data bus 2 to thereby know the current position in the sector. As a configuration for detecting a change in data on internal data bus 2, for example, a configuration similar to that of an address change detection circuit used for detecting an address change in a memory may be used. Offset detector 9 supplies a match detection signal to access sector number storage 10 when the position of the data transmitted on internal data bus 2 matches the offset value offset set in command register 7. Access sector number storage section 10 responds to the match detection signal from offset detection section 9 and stores the data currently or next provided on internal data bus 2 as reference sector identification information.

The data until the offset detector 9 detects a match is not stored in the data register 15 and is ignored. The ignoring of the data in the data register 15 may be performed in accordance with a control path (not shown) from the control circuit 6 under the control of the output of the command decoder (not shown) and the output of the offset detection unit 9, and a gate circuit (not shown). And the opening and closing of the gate circuit may be controlled by the output of the offset detection unit 9.

The data stored in the access sector number storage section 10 indicates the number (n2) of the sector to be read next. When the offset detector 9 detects a match, the drive interface 8 then inhibits the data input and connects the internal data bus 2 to the output port 12. Next, the disk controller 1 sends the data (reference sector specifying information) n2 stored in the access sector number storage 10 to the drive interface 8. The drive interface 8 sends this reference sector information to the disk unit via the output port 12 under the control of the serial interface control 13.

The reference sector information sent from the access sector number storage section 10 is taken into a sector number storage register of the command register 7 and sent from the command register 7 to the drive interface 8 via the internal data bus 2. Configurations may be used. In this case, in the indirect read mode, the direct read operation mode is successively performed twice without the application of the read command.

Alternatively, the data stored in the access sector number storage 10 may be sent directly to the internal data bus 2 and sent to the drive interface 8. Serial interface control 13
At this time, a configuration for controlling read / write of the disk unit may be used. Further, a configuration that simply issues a control signal for synchronizing data transfer may be used. At this time, control signals for read / write and the like are output to the output port 12 via the drive interface 8.
To the drive circuit of the disk unit.

Serial interface control 1
3 controls the read / write operation of the disk unit as well, in the indirect read mode, in response to the coincidence detection signal from the offset detector 9, the serial interface control 13 resets the read operation designation signal to the disk Transmit to the unit. Either configuration may be used.

The disk unit reads the contents of sector n 2 according to the newly assigned sector number n 2 and transmits the contents to input port 11 of disk controller 1. The drive interface 8 sends out the data supplied to the input port 11 onto the internal data bus 2. Data register 15 stores data transmitted from drive interface 8 onto internal data bus 2. The multiplexer 5 controls the data register 15 under the control of the control circuit 6.
Is connected to the buffer 4. A control signal indicating data transfer is sent from the control circuit 6 to the arithmetic processing unit.

At this time, a configuration may be used in which status register 14 transmits information indicating data transfer to the arithmetic processing unit prior to data transfer. That is, a status indicating that the sector indirect read mode is in progress is stored in the status register 14, and the status information from the status register 14 is transmitted to the multiplexer 5 in response to the match detection signal from the offset detector 9.
Alternatively, a configuration in which the data is sent to the arithmetic processing device via the buffer 4 may be used.

In the arithmetic processing unit, a configuration for determining whether or not desired data is transmitted according to the status information transmitted through buffer 4 may be used. That is, more specifically, the arithmetic processing unit is in a wait state while status information indicating that the indirect read mode is being performed is provided from the status register 14,
When the data information transmitted from the status register 14 changes and becomes status information indicating the data transfer mode, a configuration may be used in which the arithmetic processing unit sets the transfer data input mode.

The data of the sector n2 stored in the data register 15 is read into the memory in the arithmetic processing unit (step S33).

As described above, in the sector indirect read command, one command is used to (1) read a sector in which reference information is stored, and (2) read a sector in which data to be actually read is stored. Are executed twice. Therefore, the contents of the desired sector can be read into the memory in the arithmetic processing unit by issuing the command once, and the contents of the desired sector can be read at a high speed.

In the above-described embodiment, a file management system is shown as an example of a sector-type data storage structure. However, the present invention is not limited to such a file management system but may have a data structure of "indirect reference". In this case, the same effects as those of the above embodiment can be obtained.

In the above embodiment, the operation of reading data in a sector into a memory in an arithmetic processing unit has been described. However, in the case where the contents of the file are to be rewritten, by changing the above-mentioned indirect read command to the “indirect write” command, the rewriting of the desired sector can be executed by issuing one command.

Also, as the storage medium, a disk-shaped storage medium such as an optical disk or a magnetic disk has been described as an example, but the data storage area is divided into a plurality of blocks.
If the storage medium has a data structure having a reference relationship between different blocks, the same effects as those of the above embodiment can be obtained.

[0058]

As described above, according to the present invention, if the position (sector number and offset value) where the sector reference information is stored is specified as a parameter, the contents of the sector indicated by the sector reference information can be read out once. It can be read by issuing a command, and the data processing time for a storage medium having a data structure of indirect reference can be greatly reduced.

The provision of the disk controller makes it possible to construct a data processing system capable of executing data processing at high speed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a disk controller according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the disk controller shown in FIG. 1;

FIG. 3 is a diagram schematically showing a general configuration of a data processing system including a disk unit as an external storage device.

FIG. 4 is a diagram showing a configuration of a conventional disk controller.

FIG. 5 is a diagram schematically showing a configuration of a storage medium having a data structure of indirect reference.

6 shows a storage medium having the data structure shown in FIG.
FIG. 7 is a flowchart showing a processing operation when reading is performed by the conventional disk controller shown in FIG.

[Explanation of symbols]

 1 Disk Controller 7 Command Register 9 Offset Detector 10 Access Sector Number Storage 15 Data Register 6 Control Circuit

Claims (1)

(57) [Claims] 1. A disk controller for controlling data input / output of a storage unit having a storage medium for storing data in a sector system, wherein the disk controller indicates a position in a sector at which information for specifying a reference sector is stored. An offset detecting means for storing an offset value and detecting a match / mismatch between a current access position of the sector and the offset value; and responding to a match detection signal from the offset detecting means, Sector reference information storing means for storing the read information of a predetermined size as the reference sector specifying information; and means for accessing the reference sector according to the reference sector specifying information stored in the sector reference information storing means. , Disk controller.