JPH04353632A - High speed accessing system for optical disk - Google Patents

Abstract

PURPOSE:To perform a reading operation at a mean rotation waiting time of 1/4 of rotation by reading data of a sector previously moved to a position of a head by the rotation of a disk from two data on the same track. CONSTITUTION:Data of a sector X is written in sectors separated by (m+1)/n sector. When the data of the sector X in which a track T is accessed is read, the data of the sector moved earliest to a position of a head H by the rotation of the disk is selected from a plurality of n of sectors in which the same records are written, is read. Since a sector {(m+1)/n}+X is moved earliest to the position of the head H by the rotation of the disk, the data of {(m+1)/N}+X is read. Since a rotation waiting time can be shortened at the time of reading in this manner, its accessing can be accelerated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed access method for a disk device by reducing rotational waiting time when accessing data in the disk device.

Disk devices such as magnetic disks are widely used in the field of information processing. Disk devices have the advantage of being nonvolatile and large-capacity storage devices, but due to the seek time required to move the head when selecting a cylinder and the fact that the disk device is a rotating body, it is difficult to locate the desired sector at the position of the head. Rotation waiting time is required.

As the speed of central processing units and the like in computer systems becomes faster, there is a demand for faster access speeds of disk devices.

[0004] To this end, shortening the seek time and rotation waiting time has become an issue.

[0005]

2. Description of the Related Art Conventionally, in high-speed access systems for disk devices, shortening seek time and rotational waiting time have been problems.

[0006] As shown in Japanese Patent Laid-Open No. 2-132692, an access order memory that reduces seek time has an access order in which the amount of movement is the smallest when performing a seek operation during writing or reading. A method is known in which a table is provided and an efficient access order is controlled based on the current head position using access order conversion means.

[0007]

Disk devices, such as magnetic disk devices, do not have multiple pieces of the same data on the same track. Therefore, when accessing data recorded on a track, if the data start position is at the head position at the time of starting access, the rotational waiting time is zero; If the data start position is a little past the head position, the rotation waiting time is approximately one rotation.

[0008] As described above, in a disk device, when accessing a record, an average rotational waiting time of the time required for half a rotation is required.

[0009] When records were accessed using the conventional method, a rotation wait time of half a rotation occurred each time.

The present invention was devised in view of the above points, and an object of the present invention is to provide a high-speed access method for a disk device by reducing rotational waiting time.

[0011]

[Means for Solving the Problems] A plurality of tracks (T) are formed concentrically on the surface of a storage medium consisting of a disk (D), and a head (T) is moved in the radial direction of the disk (D).
H) accesses the track (T) to write and read data, the disk device comprising:
The track (T) is divided into sectors of fixed-length data blocks, starting from the index mark to sector 0 and sector 1.
, sector 2, sector 3... The sector number is set to sector m, and consists of (m+1) sectors.

As shown in FIG. 1, the data of sector x is (m+1)
It has a plurality of (n) sectors in which the same data is written on the same track (T) and written in sectors shifted by /n sectors.

[0013] The device is provided with means for selecting a plurality (n) sectors in which the same data is written from the track (T), and when accessing the track (T) and reading data. The system selects the sector that has reached the position of the head (H) fastest by rotation of the disk from among a plurality of (n) sectors having the same data, and reads out the data.

[0014]

[Operation] As shown in Figure 1, the data in sector X is (m+1)/n
The data is written to sectors separated by sectors. When accessing track (T) and reading data in sector
The head (H) is selected by rotating the disk from among the sectors.
Select the sector that arrived at the position fastest and read the data.

In the case of FIG. 1, sector ((m+1)/n)+
Since X comes to the head (H) position fastest due to the rotation of the disk, data in sector ((m+1)/n)+X is read.

[0016] In this way, the rotational waiting time during reading can be shortened and access can be speeded up.

[0017]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 2 and 3.

In this embodiment, the same track has two pieces of the same data.

FIG. 2 shows the configuration of an embodiment of the present invention. In FIG. 2, 1 is a host device. Reference numeral 2 denotes a control device; 3, a plurality of tracks are formed concentrically on the surface of a storage medium consisting of a disk; the tracks are accessed by a head that moves in the radial direction of the disk to write and read data; It is a disk device.

The host device 1 and the disk device 3 are the control device 2
connected via. The host device 1 is connected to the disk device 3 via a data bus 4 and a buffer 5 . The operation signal 16 from the host device 1 is sent to the disk controller 12.
The disk controller 12 outputs a head position sector number read signal 13 and a read/write command signal 1.
4 is connected to the disk device 3. Disk device 3
A head position sector number signal from the head position sector number signal is connected to a comparator 11 via a head position sector number storage register 10. A logical sector number signal 6 from the host device 1 is connected to a comparator 11 via a physical sector calculation circuit 7 and a physical sector storage register 8. The physical sector identification signal 15 from the comparator 11 is connected to the disk controller 12.

FIG. 3 shows the disk (
D) is a diagram showing the surface of a storage medium consisting of tracks (T
) indicates that two pieces of the same data have been written. The disk (D) rotates around O in the counterclockwise direction of the arrow. The track (T) is divided into sectors of (m+1) fixed length data blocks, and sector numbers are set as sector 0, sector 1, sector 2, sector 3, . . . sector m from the index mark. However, m+1 is 2
Assume that it is divisible by .

The sector has the configuration shown in FIG. 4, which shows that it is composed of a sector address section 17 for storing sector addresses and a data section 18 for storing data.

Next, the operation of the above embodiment will be explained.

When writing data to the sector X address of the track (T), the operation signal 16 and the sector
A logical sector number signal 6 indicating .

The physical sector number calculation circuit 7 calculates a target physical sector number from the designated sector number signal 6. When the logical sector number signal 6 is X, the target physical sector number is X and ((m+1)/2)+X. The two calculated physical sector numbers are stored in two physical sector number storage registers 8, respectively.

Next, a head position sector number read signal 13 is sent from the disk control device 12 to the disk device 3, and the sector number section 1 of the sector located at the head (H) position is sent to the disk device 3.
7 is read out, transmitted as head position sector number signal 9, and held in the head position sector number storage register. The contents of the two physical sector number storage registers and the head position sector number storage register are compared by a comparator 11, and the result is transmitted to the disk controller 12 by a physical sector identification signal.

As a result of the comparison, if the head position sector number does not match either of the two physical sector numbers, a head position sector number read signal 13 is sent from the disk control device 12 to the disk device 3, and the next head position is determined. The sector number is read and the comparison between the head position sector number and the physical sector number is repeated.

When the head position sector number matches one of the two physical sector numbers, the disk controller 1
A write command signal 14 is transmitted from 2 to the disk device 3, and a write operation is performed. Data to be written is transferred from the host device 1 to the disk device 3 via the data bus 4 and written into the data section 18 of the sector. Further, the transferred data is held in the buffer 5.

Thereafter, the comparison between the head position sector number and the physical sector number is repeated, and when the head position sector number and the other physical sector number match, the write command signal 14 is transmitted from the disk controller 12 and a write operation is performed. However, the data held in the buffer 5 is written into the data portion 18 of the sector.

With the above operation, sector X and sector ((m+1
)/2) The same data is written to +X.

When reading data at sector X address from track (T), similar to the above write operation,
An operation signal 16 and a logical sector number signal 6 indicating sector X are transmitted from the host device 1, and the physical sector number calculation circuit 7
The target physical sector number X and ((m+1)/2)+
X is calculated.

Next, the comparison between the head position sector number and the physical sector number is repeated, and the head position sector number and 2
When any of the target physical sector numbers match, a read command signal 14 is transmitted from the disk controller 12, and a read operation is performed.

In FIG. 3, sector X and sector ((m+1)
/2) Out of +X, the head (H
) The data in sector ((m+1)/2)+X located at position is read out.

The data read from the data section 18 of the sector is transferred to the host device 1 via the data bus 4, and the read operation is completed.

In this way, in this embodiment, the track (T)
When reading the above data, the control device 2 selects the head (H) from among the multiple pieces of data by rotating the disk.
By reading the data of the sector that comes first at the position, the rotational waiting time is shortened and the read operation of the disk device is made faster.

[0036]

[Effects of the Invention] As explained above, according to the present invention,
In the read operation of a disk device, if there are no multiple pieces of the same data, an average rotational waiting time of half a rotation was required, but when there are two pieces of data on the same track, it is necessary to wait for the rotation of the disk. By reading the data of the sector that comes first to the head position, a read operation can be performed with an average rotational waiting time of 1/4 rotation.

[0037] In this way, the rotation waiting time can be shortened, which is effective in speeding up the read operation of the disk device.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a high-speed access method of a disk device according to the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is a diagram showing the surface of a storage medium of a disk device in an embodiment of the present invention.

FIG. 4 is a diagram showing a sector configuration in an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Upper device, 2... Control device, 3... Disk device, 4... Data bus, 5... Buffer, 6... Logical sector number signal, 7... Physical sector number calculation circuit, 8... Physical sector number storage register, 9... Head Position sector number signal, 10... Head position sector number storage register, 11... Comparator, 12... Disk control device, 13... Head position sector number read signal, 14... Read/write command signal, 15... Physical sector identification signal, 16 ...Operation signal, 17...Sector number part.

Claims (1)

[Claims] 1. A plurality of tracks (T) are formed concentrically on the surface of a storage medium consisting of a disk (D), and the tracks (T) are tracked by a head (H) that moves in the radial direction of the disk (D). A disk device like the one shown in FIG. 1 that accesses and writes and reads data, the track (T) is divided into sectors of (m+1) fixed length data blocks, and the track (T) is divided into sectors of (m+1) fixed-length data blocks. To, (m
+1)/having multiple (n) pieces of the same data written in sectors spaced apart by n sectors,
The device is equipped with a means for selecting a plurality (n) sectors in which the same data is written from the track (T), and when accessing the track (T) and reading data, the plurality (n) sectors are selected from the track (T). A high-speed access method for a disk device characterized in that rotation waiting time is shortened by reading out a sector that reaches the position of a head (H) fastest due to disk rotation from among sectors having the same data.