JPH04238527A - Data transferring method - Google Patents

Abstract

PURPOSE:To execute data transfer at higher speed in a disk array device. CONSTITUTION:The data transfer on a data bus which the disk of each row executes can be executed continuously without competing with each other by arranging disk devices capable of executing simultaneously the data transfer in the form of the row, and distributing uniformly the phases of the rotation synchronism of the disk devices of each row so as to shift the timing of the start and the end of the read/write of each disk device.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transfer method in a disk array device serving as an external storage device for a computer.

0002

2. Description of the Related Art A disk array device connects a plurality of disk devices to realize both large capacity and high-speed transfer. The basic configuration of a disk array device for achieving large capacity is one in which a plurality of disk devices are connected in a daisy chain configuration, as shown in FIG. In FIG. 2, 1 is a host computer, 2 is a control device, 3 is a data buffer, 4 is a control unit, 5 is a data bus, 6 is a control bus, and 7 is a disk device.

A disk array device for realizing both large capacity and high-speed transfer is a system in which a plurality of daisy chain type disk devices shown in FIG. 2 are connected as shown in FIG. 3, and each data buffer 3A, 3B is ...Data can be transferred to 3N at the same time.

In such a disk array device that can perform data transfer simultaneously, the disk devices in the first row, second row, or subsequent rows, for example, the disk devices 7A1, 7B1, . . . 7N1 in the first row, are rotated. Synchronous control device 8
In this method, the rotations are synchronized and the average rotation waiting time is half of the rotation time. The rotation synchronization control device 8 transmits an index pulse to the disk devices in each row, and the disk devices align the index mark on the medium with the index pulse. Then, set the logical address to the disk devices 7A1 and 7B in the first column.
1...7N1, and the next largest logical address in the first column is assigned to the disk devices 7A2, 7B2...7N2 in the second column.

When reading, the column from the logical address is calculated, the data is read from the disk device in that column, and the data division and synthesis device 9 stores the data in the data buffer 3.
Connect the data on A, 3B...3N.

When writing, calculate which column from the logical address, and write the data to the data buffer 3A.
, 3B, . . . , 3N, the data is divided by the data division/synthesis device 9 and written to the disk device of that column.

FIG. 4 shows a timing chart of data transfer during read in such a conventional disk array device. This is similar to the data transfer operation in one disk device. The buffer in the disk device is
It is assumed that reading or writing from the disk and transferring to the data buffer cannot be performed at the same time.

In FIG. 4, first, a read signal b for one track is read from the medium by an index pulse signal a sent from the rotation synchronizer 8 to the disk device, and the read signal b is used as a transfer signal c to transfer data through the data bus. Transfer to buffer. Normally, the transfer speed to the data buffer is sufficiently higher than the read/write speed, so the transfer speed of the disk array device is ultimately proportional to the number of disk devices that can transfer data simultaneously.

[0009] In this way, even in the conventional disk array device, high-speed transfer can be realized by transferring data to a plurality of disk devices at the same time.

0010

[Problems to be Solved by the Invention] However, in the conventional data transfer method described above, the data transfer speed is proportional to the number of disk devices that can perform data transfer simultaneously. There was a problem in that the number of items had to be increased.

[0011] Increasing the number of disk devices that can perform data transfer at the same time increases the number of data buses and control buses, which in turn increases the number of bus cables, connectors, wiring on the board, and data buffers, resulting in high costs. However, there was a problem in that the capacity of the device increased.

[0012] The present invention is intended to solve these conventional problems, and it is an object of the present invention to provide a data transfer method that can realize high-speed transfer without increasing the size of the device.

[0013]

[Means for Solving the Problems] In order to achieve the above object, the present invention arranges disk devices that can perform data transfer simultaneously in a row, and evenly distributes the rotational synchronization phase of the disk devices in each row. The read/write start and end timings of each disk device are staggered.

[0014]

[Operation] With the above configuration, the present invention uniformly shifts the read/write start and end timings of the disk devices in each column, thereby avoiding conflicts in data transfer on the data bus performed by the disk devices in each column. This can be done continuously.

[0015]

[Embodiment] An embodiment of the present invention will be described below. The system configuration for implementing the present invention is almost the same as the conventional system configuration shown in FIG. The difference is Figure 3
In the conventional device, the rotation synchronization control device 8 inside simply sends an index pulse to the disk device.
This embodiment has a function of shifting the index pulses sent to the disk drives in each row so that the rotational synchronization phases of the disk drives in each row can be evenly distributed. In other words, one rotation of 360° is shifted by 180° for up to the second row, and 120° for up to the third row.
Shift by °.

FIG. 1 shows an embodiment of the present invention, and shows a timing chart of data transfer during reading in a disk array device in which disk devices are connected in three rows.

When reading, after a command is issued to the disk devices in each column, the disk device in the first column reads data from the disk medium, and then transfers the data to the data buffer. In parallel, reading of the second row of disk devices is also performed with a 120 degree delay from the read of the first row of disk devices. Starts data transfer for the disk device. The same applies to the third row disk device. In this way, the read start and read end of the disk devices in each column are synchronized, so
Data bus usage sections do not overlap, allowing continuous data transfer.

When writing, when the data to be written is received in the data buffer, the data is divided and transferred to the first row of disk devices, and immediately after the transfer is completed, the data to be written is transferred to the data buffer. received in
Data is transferred to the second row of disk devices, and the third row of disk devices operates in the same manner.

As described above, according to the above embodiment, since the rotational synchronization phases of the three rows of disk devices are equally shifted by 120 degrees, data can be transferred at three times the conventional data transfer speed. be able to.

According to the method of the present invention, the larger the ratio between the data transfer speed on the data bus and the read/write speed from the medium, the more the number of rows of disk devices can be increased. The transfer speed of the disk array can be increased within the range where transfer interval conflicts do not occur.

[0021]

Effects of the Invention As is clear from the embodiments described above, the present invention arranges disk devices that can perform data transfer simultaneously in a row, and evenly distributes the phase of rotational synchronization of the disk devices in each row. Since data transfer is performed by shifting the read/write start and end timings of the disk array device, the transfer speed of the disk array device can be increased.

[Brief explanation of the drawing]

FIG. 1 is a timing chart showing data transfer during reading in an embodiment of the present invention.

[Figure 2] Block diagram showing the basic configuration of a disk array device connected in a conventional daisy chain type

[Figure 3] Block diagram showing the system configuration of a conventional disk array device

[Figure 4] Timing chart showing data transfer during read in a conventional disk array device

[Explanation of symbols]

1. Host computer 2 Control device 3 Data buffer 4 Control section 5 Data bus 6 Control bus 7 Disk device 8 Rotation synchronous control device 9 Data division and synthesis device

Claims (1)

[Claims] Claim 1: Disk devices that can perform data transfer simultaneously are arranged in a row, the rotational synchronization phase of the disk devices in each row is evenly distributed, and the read/write start and end timing of each disk device is A data transfer method characterized by performing data transfer by shifting the .