JPH0388177A - Accessing method in compact disk player - Google Patents

Abstract

PURPOSE:To shorten waiting time by performing track jump to the inside of a disk when a difference (ATN-ATP) is less than prescribed time, and repeating an access operation so as to be set within a range when it exceeds the prescribed time. CONSTITUTION:When the present location is positioned at an outer peripheral side than a designated address, it is judged whether or not a difference between accumulation time ATN after access and accumulation time ATP before access is less than the prescribed time, for example, three seconds. When it is less than three seconds, the track jump to the inside of the disk by (ATN- ATP)DELTASCT i.e. the number of tracks equivalent to the difference between the ATN and the ATP is performed. When it exceeds three seconds, an operation is repeated until the ATN coincides with the ATP. Also, the ATP shows the accumulation minute, second, and sector time of the designated address at a data readout starting position, and the ATN shows the accumulation minute, second, and sector time of the designated address read after access, and DELTASCT is the number of sectors of one track at the designated address position.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an access method in a compact disc player.

Conventional technology In a compact disc player having a track conversion table corresponding to the cumulative address frame and second data,
As a method of accessing an address with specified minutes, seconds, and sectors, the current position, that is, the cumulative time ATN including the minutes, seconds, and sector time of the specified address read after access,
Refer to the conversion table to calculate the number of tracks corresponding to each minute and second data of the cumulative time ATP including minutes, seconds, and sector time of the specified address at the target position, that is, the reading start position of the specified data read before access. Then, find the difference between the two and access a predetermined number of tracks. For example, the access is completed when the second data of the cumulative time ATH after access is within the range of 1 second before the value of the cumulative time ATP before access. However, the data was read at the location that matched the specified address.

Problems to be Solved by the Invention However, in the above-mentioned conventional access method, if the sector at the specified address is, for example, 74 sectors, one second is 75 sectors, so it takes a long time to wait from the completion of the access until the data at the specified address is read. There was a problem in that a maximum of 2 seconds was required.

The present invention solves these conventional problems,
It is an object of the present invention to provide an excellent access method for a compact disc player that allows high-speed access.

Means for Solving the Problems In order to achieve the above object, the present invention sets the number of sectors ΔSCT for one track at a specified address position,
The value of cumulative time ATN read after access is the number of sectors ΔS for one track before the cumulative time ATP before access.
The access operation is completed when the data is within the range of CT, thereby shortening the waiting time until data at a designated address is read.

Operation The present invention has the effect that, with the above-described configuration, it is possible to shorten the waiting time until data at a designated address is read, thereby speeding up the access time.

Embodiment FIG. 1 is a flow chart for explaining an access operation in an embodiment of the present invention.

To start the operation, first, when a disk is loaded into the device, the optical pickup accesses the disk glue-in track, reads the cumulative time ATP of the addresses of all the data recorded on the loaded disk, and reads the accumulated time ATP of the addresses of all the data recorded on the loaded disk. Stored in RAM. On the other hand, the address of the required data is input from the numeric keypad of the input section, and similarly
Stored in AM.

When access starts, the optical pickup moves from the inner radial side to the outer radial side of the disk, the number of tracks crossed during this movement is calculated, and the number of tracks crossed is calculated as the cumulative time before access. The number of tracks calculated from ATP is successively compared, and when that value is reached, the optical pickup is braked and the cumulative time ATN at that track position is read.

As shown in FIG. 1, in step 1, the cumulative time ATP before access and the cumulative time ATN after access are compared, and ATN is smaller than ATP, that is, the current position is located on the inner side of the specified address. If so, in step 2 it is determined whether the difference between ATP and ATN is less than a predetermined time, for example, 3 seconds. If it is less than 3 seconds, check in step 3 whether ATN is within the range of the value obtained by subtracting the number of sectors ΔSCT for one track from ATP, that is, whether it is within the range of the track one track before the specified address. It is determined whether or not. When it is determined that the address is within the range of the previous track, the access operation is completed and the play mode (data read mode) is entered, and the data is read out at the time when the address is waited until it matches the specified address. On the other hand, if it is determined that it is outside the range of the previous track, step 4 moves to the outer circumference of the disk (ATP-ATN)/ΔSCT, that is, the difference between the cumulative time ATP before access and the cumulative time ATN after access. A track jump is performed for the number of tracks, and then the data is read again in step 8. After the reading is completed,
Return to step 1.

In step 1, if the cumulative time ATN after access is greater than the cumulative time ATP before access, that is, if the current position is located on the outer periphery side of the specified address, in step 6, the difference between ATN and ATP is determined by a predetermined value. It is determined whether the time is less than 3 seconds, for example. If the time is less than 3 seconds, step 7 moves toward the inner circumference of the disk (A
TN-ATP)/ΔSCT, that is, a track jump is performed for the number of tracks that is the difference between the cumulative time ATN after access and the cumulative time ATP before access, and then data is read again in step 8, and after reading is completed, the process returns to step 1. .

If ATP-ATN is 3 seconds or more in step 2 and ATN-ATP is 3 seconds or more in step 6, a normal access operation is performed in step 5 with the number of tracks corresponding to the difference between ATP and ATN. Then, in step 8, the data is read again, and after the reading is completed, the process returns to step 1.

In this way, the above operations are repeated until the post-access cumulative time ATN matches the pre-access cumulative time ATP, or until the pre-access cumulative time ATP falls within the range of the previous track. .

Here, the number of sectors ΔSCT for one track can be found by first finding the number of tracks Tn from the following equation (1), and then substituting that value into equation (2).

V-t-Tp=-r((Tp・Tn+ro)-ro
)・・・・・・・・・(1) V: Linear velocity [m/s] t: Time (address) [seconds] rO Niprogram area innermost radius [m1Tp:) Rack pitch [mTn:) Number of racks △S CT = 75 / T n / t ・
−・−・・・(2) This ΔSCT can be sequentially calculated by the microcomputer of the compact disc player, but in this example, in order to simplify the configuration, it is calculated from the above equation (2). Based on the obtained value, divide the specified address (minutes) into predetermined blocks as shown in Figure 2, and calculate the number of sectors ΔS for one track corresponding to each block.
A data table representing CT is created, and ΔSCT is set and used based on the data table.

Effects of the Invention As is clear from the above embodiments, the present invention performs a track jump corresponding to the difference in the number of tracks after accessing a specified address within a predetermined time period, for example, less than 3 seconds, before and after the specified address, and then performs a read after the access. Accumulation valve with specified address,
The access operation is completed when the second, sector time is within the value obtained by reducing the number of sectors for one track at the specified address position from the cumulative value, seconds, sector time of the specified address at the specified read start position. This has the advantage that it is possible to shorten the waiting time until data at a designated address is read and to speed up access.

[Brief explanation of drawings]

FIG. 1 is a 70-chart for explaining the access operation of a compact disc player in one embodiment of the present invention, and FIG. 2 is the number of sectors for one track into which the designated address time is divided in one embodiment of the present invention. This is a table chart. ATP...Accumulation value, seconds, sector time, ATN... of the specified address at the specified data read start position.
- Cumulative valve, seconds, sector time of the specified address read after access, ΔSCT: Number of sectors for one track at the specified address position.

Claims (1)

[Claims] The cumulative time ATP of the designated address at the designated data read start position is greater than the cumulative time ATN of the designated address read after access, and the difference between the two is ATP-A.
If TN is less than the predetermined time, the cumulative time after access AT
The access operation is completed when the value of N is within the range of the cumulative time ATP before access minus the number of sectors ΔSCT for one track at the specified address position, and when it is outside that range, the disk is to the outer periphery of (ATP-A
TN)/ΔSCT, and if the cumulative time ATP before the access is smaller than the cumulative time ATN after the access, and the difference between the two ATN-ATP is less than a predetermined time, the track jump is performed to the inner circumference of the disk. (ATN-
ATP)/ΔSCT is performed, and if the difference between the cumulative time ATP before the access and the cumulative time ATN after the access is a predetermined time or more, a normal access operation is performed so that the cumulative time ATN after the access is the same as the cumulative time ATN after the access. An access method for a compact disc player characterized by repeating an access operation so as to be within the range.