JPH11305951A - Magnetic disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the access time by building a dual port memory into a magnetic disk device to temporarily store the data and simultaneously executing both writing and reading operations to the dual port memory. SOLUTION: A magnetic disk device contains an HDC(hard disk controller) 3, a dual port memory 4 which temporarily stores the data, etc. A buffer control part 32 includes a 1st control circuit which is connected to one of both ports and generates an address, a 2nd control circuit which is connected to the other port and generates an address and a limiter circuit which is connected to one of both ports, transmits a limiter signal when coincidence is confirmed between the prescribed limit value and the address of one of both ports and temporarily stops the transmission of data at a host protocol control part 31. Thus, both writing and reading operations can be simultaneously executed with respect to the memory 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic disk drive.

[0002]

2. Description of the Related Art Generally, a magnetic disk device is used as an auxiliary storage device of a personal computer, a work station or the like. This type of magnetic disk device has a function of receiving data according to an instruction from a higher-level device and writing the data on a magnetic disk, and a function of reading data written on the magnetic disk. Further, the magnetic disk device includes a mechanical mechanism unit in which a magnetic head, a magnetic disk medium, a spindle motor, and a VCM (voice coil motor) are integrated, and an electronic circuit unit that controls them.

Reading and writing data on a magnetic disk requires time for moving the magnetic head and time for reading and writing in synchronization with the rotation of the motor. Therefore, when writing to the magnetic disk, the data from the host device is temporarily stored in the memory, and the contents of the temporarily stored memory are stored in the magnetic disk after moving the magnetic head and waiting for the rotation of the motor. Write to. The time required for reading and writing is called an access time, and it is desirable that the access time be as short as possible.

[0004] An example of shortening the access time is disclosed in, for example, JP-A-1-150953 as a disk cache device. This disk cache device
A determination unit that determines whether a corresponding disk block exists on the disk cache memory; an access information management unit that manages access information for the disk block; a read-ahead mechanism that pre-reads the disk block; and the disk cache memory. A disk management device comprising: a disk cache memory control unit for controlling; and a disk control unit for issuing a command to the disk device.
And a disk cache memory comprising a dual port memory. In this disk cache device, one port of a disk cache memory composed of a dual port memory is connected to a system bus,
The other port is connected to a disk device.

[0005] This disk cache device realizes an apparently high-speed auxiliary storage device by combining a dual port memory and a disk device. That is, since one port of the disk cache memory composed of the dual port memory is connected to the system bus and the other port is connected to the disk device, the cache memory mishit in reading data from the auxiliary storage device is achieved. At the time of data update, the required system bus bandwidth can be reduced.

[0006]

However, when the required information is not in the dual port memory, the above disk cache device needs to wait until reading from the disk device is completed. Therefore, the processing time depends on the read / write speed of the disk device itself.

It is an object of the present invention to provide a magnetic disk device capable of shortening an access time by improving a dual port memory for temporary storage and its control unit.

[0008]

According to the present invention, there is provided a magnetic disk drive which receives data according to an instruction from a host device and writes the data on a magnetic disk, reads data written on the magnetic disk and sends the data to the host device. , A dual port memory for temporarily storing data is provided, and a buffer control unit capable of simultaneously executing a write operation and a read operation with respect to the dual port memory is provided.

In the dual port memory, one port is used for exchanging data with the host device, and the other port is used for exchanging data with the magnetic disk. Transfer of data with the host device is performed via a host protocol control unit. The buffer control unit includes a first address control circuit for generating an address connected to the one port, and the other port. A second address control circuit for generating an address, connected to the one of the ports, and transmitting a limiter signal when an address at the one of the ports matches a preset limit value with the one of the ports. And a limiter circuit for temporarily suspending data transmission in the control unit.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a magnetic disk drive according to the present invention has a hard disk controller (hereinafter referred to as HDC) comprising a host protocol controller 31, a buffer controller 32, and a format controller 33. Abbreviated) 3, a dual port memory 4 for temporarily storing data, and read / write (hereinafter abbreviated as R / W) control for converting data from the HDC 3 into an analog signal and writing the analog signal to a disk medium. A head 5, a head disk assembly (hereinafter abbreviated as HDA) 7, which is a mechanical mechanism comprising a magnetic head (hereinafter referred to as a head), a disk medium, a VCM, and a spindle motor. And a CPU 2 for controlling the above-mentioned components.

The R / W control unit 5 converts digital data from the HDC 3 into an analog signal and sends it to the head of the HDA 7 when writing to the disk. When reading from the disk, the analog signal from the head of the HDA 7 is converted into digital data and transmitted to the HDC 3. In addition, it has a function of selecting a plurality of heads and a function of notifying the CPU 2 of a head abnormality according to a command from the CPU 2.

The positioning circuit 6 has a function of controlling the VCM of the HDA 7 to move or fix the head to an arbitrary position in accordance with a command from the CPU 2, and a function of starting and stopping the spindle motor and maintaining a steady rotation. Have. Further, the CPU 2 can be notified of information on the completion of positioning and a positioning error.

The HDA 7 can mount a plurality of disk media and heads. The disk media is rotated by a spindle motor, and the spindle motor is controlled by a positioning circuit 6. The head moves by driving the VCM,
Is controlled by the positioning circuit 6.

CPU 2 is a ROM for storing programs
And a RAM for storing temporary data when operating various parameters and programs, and controls the HDC 3, the R / W control unit 5, and the positioning circuit 6 to control the entire function of the magnetic disk device. There is. Further, the CPU 2 monitors the HDC 3 to receive a command from the host device 1 to perform control for writing / reading data, and to constantly control the state of the HDC 3, the R / W control unit 5, and the positioning circuit 6. Can be monitored.

Next, the general functions of the HDC 3 will be described with reference to FIG. 2, and in particular, the operations of the buffer control unit 32 and the dual port memory 4 will be described in detail. As described with reference to FIG. 1, the HDC 3
1, a buffer control unit 32 and a format control unit 33.

The host protocol control section 31 manages communication with the host device 1. Usually, a common communication method is a SCSI interface or an I / O interface.
There is a DE interface. Data used for communication can be classified into commands and data. The commands include a data write command, a data read command, a command for changing or confirming parameters of the magnetic disk device, and a command for sensing or canceling a disk error.

The data includes data to be stored in a disk, data to be read from the stored data and passed to a higher-level device, and parameters and error data of a magnetic disk device. A command is provided at the head of the data, and the type of the data can be determined by the command.

Next, the operation of the host protocol control unit 31 will be described. Upon receiving data from the host device 1, the host protocol control unit 31 distinguishes between a command and data. 3 and 4 are time charts of data and signals between the host protocol control unit 31 and the buffer control unit 32.

With reference to FIG. 3, a description will be given of a process until data from the host protocol control unit 31 is written to the dual port memory 4 via the buffer control unit 32. The data sent from the host device 1 is sent out to the buffer control unit 32 via the data bus A. The control bus A sends out a clock signal a and a write enable signal b synchronized with one byte of data. When the limiter signal c is received from the buffer control unit 32, the operation is temporarily stopped. When the limiter signal c is released, the operation is continued. This limiter signal c monitors the address on the port A side of the dual port memory 4, and the limiter value is
Set in 2. The CPU 2 sets the limiter value in consideration of no waiting time between the format control unit 33 and the host protocol control unit 31. Usually, the CPU 2 sets the limit value of the capacity of the dual port memory 4 so that the memory overflow occurs. Check.

Next, a description will be given of a process until data from the dual port memory 4 is transmitted to the host protocol control unit 31 via the buffer control unit 32 with reference to FIG. When sending data to the host device 1, data from the dual port memory 4 is sent to the host protocol control unit 31 via the data bus A of the buffer control unit 32. The timing is defined by the clock signal a and the read enable signal b.

Next, a control operation between the CPU 2 and the host protocol control unit 31 will be described. The host protocol control unit 31 that has received the command from the host device 1 notifies the CPU 2 when receiving the command. Notified CP
U2 accesses the host protocol control unit 31 to check the contents of the command and reads the contents. Read the logical block address and the number of logical blocks from the command, calculate the physical address from the logical block address,
The cylinder address is sent to the positioning circuit 6 to move the head to a target position. Also, if the head address is R /
The head is transmitted to the W control unit 5 to select a head. In this way, the position for writing data to the disk is specified. When data is read from the disk, the position is specified in the same manner.

Next, a control operation between the format control unit 33 and the buffer control unit 32 will be described. Writing from the host protocol control unit 31 to the dual port memory 4 is performed via the port A, while the other port B
Then, the data of the dual port memory 4 is transmitted to the format control unit 33 by the clock signal a and the read enable signal b which are the control bus B of the format control unit 33 (see FIG. 5).

The control bus B for the clock signal a and the read enable signal b is transmitted immediately after searching for a target sector in accordance with an instruction from the CPU 2, the data is added with format data, and the R / W controller 5 (See FIG. 7).

In the operation of reading data from the disk, the format control unit 33 sends the data to the data bus B at the timing of the clock signal a of the control bus B and the write enable signal b immediately after searching for a sector according to an instruction from the CPU 2. Then, the data is written to the dual port memory 4 via the buffer control unit 32 (see FIG. 6). At this time, the data is sent from the R / W control unit 5 to the format control unit 33 in the format shown in FIG.

Next, the buffer controller 32 will be described. The buffer control unit 32 includes the host protocol control unit 3
1 and a controller for receiving data from the format controller 33 and storing the data in the dual port memory 4.
The configuration includes an address control circuit A32a, an address control circuit B32b, and a limiter circuit 32c. The address control circuit A32a counts the address in increments by the clock signal a from the control bus A and generates the address. Also, a start address is set in advance by the CPU 2 before accessing the dual port memory 4.

The address control circuit B32b includes a control bus B
The address is incremented by the clock signal "a" from, and an address is generated. Also, a start address is set in advance by the CPU 2 before accessing the dual port memory 4. Limiter circuit 32c
The CPU 2 sets a limiter value. When the limit value matches the port A address, the limiter signal c is transmitted. Upon receiving the limiter signal c, the host protocol control unit 31 suspends data transmission. Further, the CPU 2 includes a host protocol control unit 3
Recognizing that the limit value has been reached from 1, the format control unit 33 confirms the completion of data reception from the dual port memory 4, and then resets the start address in the address control circuit A32a. Usually, an initial value is set. Further, the resetting cancels the limiter signal from the limiter circuit 32c by resetting, and the host protocol control unit 31
The following data is transmitted from. However, it is assumed that the limit value is not reached in normal operation by increasing the memory capacity of the dual port memory 4.

The limiter circuit 32c is used when sending data from the host protocol control unit 31 to the dual port memory 4, and does not function when sending data from the dual port memory 4 to the host protocol control unit 31. Because the amount of data read from the disk can be controlled by the CPU 2, the format control unit 33
This is because when the data is sent to the dual port memory 4 from, the memory is not over.

Referring to FIGS. 8 and 9, a magnetic disk drive using a memory with one address bus and a data bus (FIG. 8) and a magnetic disk drive according to the present invention (FIG. 9)
And are compared. FIG. 8A shows an operation when writing data for one track to a disk. It is assumed that data 1 from the host device is data to be written to track n. Data 1 is temporarily stored in the memory in operation 1. In the operation 2, when the seek is completed, the temporarily stored memory is formatted on the disk. The processing time at that time requires time T1. Here, the seek refers to an operation of moving the head to a target track. The format means an operation of writing data in synchronization with a rotating disk.

FIG. 8B shows the operation when writing data for three tracks to the disk. It is assumed that data 1, data 2, and data 3 from the host device are data to be written to track n, track (n + 1), and track (n + 3). Data 1 is temporarily stored in the memory in operation 1. In the operation 2, when the seek is completed, the temporarily stored memory is formatted on the disk. Next, in operation 1, data 2 is temporarily stored in the memory. In the operation 2, when the seek is completed, the temporarily stored memory is formatted on the disk. Further, in operation 1, data 3 is temporarily stored in the memory. In the operation 2, when the seek is completed, the temporarily stored memory is formatted on the disk. The processing time at this time requires time T2.

As described above, in a magnetic disk drive using a memory having only one address bus and data bus, the operation of receiving data from a host device and the operation of formatting a disk can be performed simultaneously. Can not.

On the other hand, in FIG. 9A, it is assumed that data 1 from the host device 1 is data to be written to track n. Data 1 is stored in the memory from port A of dual port memory 4 in operation 1. at the same time,
The seek of operation 2 is performed, and the disk is formatted via the port B of the dual port memory 4. The processing time at that time is time T3.

FIG. 9B shows the operation when writing data for three tracks to a disk. It is assumed that data 1, data 2, and data 3 from the host device 1 are data to be written to track n, track (n + 1), and track (n + 3). In operation 1, data 1, data 2, and data 3 are sequentially transmitted to port A of dual port memory 4.
From the memory. At the same time, a seek is performed in operation 2 and the disk is formatted via the port B of the dual port memory 4. The remaining two tracks are also formatted one after another. The processing time at this time is time T4.

As described above, in the conventional device having a memory with one address bus and one data bus, the processing time T1
Alternatively, while the processing time T2 is required, in the present invention, the processing time T3 is shorter than the processing time T1, and the processing time T4 is shorter than the processing time T2. Therefore, there is an advantage that the data reception from the host device and the operation of writing the received data to the disk can be performed almost simultaneously, and the access time of the magnetic disk device is reduced.

[0034]

As described above, according to the present invention, it is possible to provide a magnetic disk drive capable of shortening the access time by improving the dual port memory and its control unit.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a magnetic disk drive according to the present invention.

FIG. 2 is a block diagram showing a connection relationship between a configuration of a buffer control unit shown in FIG. 1 and peripheral components.

FIG. 3 is a time chart of data and signals when data is transmitted from a host protocol control unit to a buffer control unit.

FIG. 4 is a time chart of data and signals when data is sent from the buffer control unit to the host protocol control unit.

FIG. 5 shows a time chart of data and signals when data is sent from the buffer control unit to the format control unit.

FIG. 6 is a time chart of data and signals when data is sent from the format control unit to the buffer control unit.

FIG. 7 is a diagram showing an example of a sector format.

FIG. 8 is a diagram for explaining an operation for writing data to a disk and a processing time in the conventional device, and FIG.
Shows the case for one track, and FIG. 13B shows the case for three tracks.

9A and 9B are diagrams for explaining an operation and a processing time for writing data to a disk in the magnetic disk device according to the present invention, wherein FIG. 9A is for one track and FIG. Show.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High-order apparatus 2 CPU 3 Hard disk controller (HDC) 4 Dual port memory 5 Read / write (R / W) control part 6 Positioning circuit 7 Head disk assembly (HDA)

Claims (2)

[Claims] 1. A magnetic disk device that receives data according to an instruction from a higher-level device and writes the data to a magnetic disk, reads data written on the magnetic disk, and sends the data to the higher-level device. A magnetic disk device, comprising a dual port memory for performing a write operation and a buffer control unit capable of simultaneously executing a write operation and a read operation with respect to the dual port memory. 2. The magnetic disk device according to claim 1, wherein one port of the dual port memory is used for transmitting and receiving data to and from the host device, and the other port is used for transmitting and receiving data to and from the magnetic disk. The transfer of data between the one port and the host device is performed via a host protocol control unit, and the buffer control unit includes a first port for generating an address connected to the one port. An address control circuit, a second address control circuit for generating an address connected to the other port, and a preset limit value connected to the one port and an address at the one port match the address at the one port. A limiter circuit for transmitting a limiter signal at a time to temporarily suspend transmission of data in the host protocol control unit. A magnetic disk drive comprising: