JP3305365B2 - Buffering method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buffering method for transferring data read from a disk to an external device.

[0002]

2. Description of the Related Art In a disk drive device, data recorded on a disk is read in units of sectors, and the read data is transferred to an external device via a buffer memory. As a buffering method for data transfer using the buffer memory, a single buffering method, a double buffering method, and a ring buffering method are known.

[0003] In order to explain these buffering methods, a schematic configuration of a disk drive device will be described first. In a disk drive device, FIG.
The disk 1 is mounted on the turntable 2 and is rotated by the spindle motor 3 as shown in FIG. Data is written on the disk 1 by the optical pickup 4 during recording, and data recorded on the disk 1 is read by the optical pickup 4 during reproduction. The pickup 4 is mounted on a slider (not shown) that moves in the radial direction of the disk 1. The pickup 4 includes a modulation / demodulation circuit 5, an error correction circuit 6, and a buffer RAM.
7 are connected in order. When recording, buffer RAM 7
After the data held in the error correction circuit 6 corrects the error, the data is converted by the modulation / demodulation circuit 5 for recording and supplied to the pickup 4 as recording data. On the other hand, at the time of reproduction, the read data from the pickup 4 is demodulated by the modulation / demodulation circuit 5, further error-corrected by the error correction circuit 6, and
AM7. Each operation of the modulation / demodulation circuit 5, the error correction circuit 6, and the buffer RAM 7 is controlled by the control circuit 8. The control circuit 8 is formed of, for example, a microcomputer, and performs a control operation according to a program stored in the ROM 9 in advance. Further, the control circuit 8 also performs control operations of a disk such as a focus servo and a tracking servo and a pickup drive system (not shown). The buffer RAM 7, which is a buffer memory, is 64Kbyt
It has a capacity of e (kilobytes), is connected to the input / output port 10, and performs a buffering operation for data transfer with the host computer 11, which is an external device. In FIG. 1, a portion surrounded by a dashed line is a disk drive device.

The disk 1 is divided into 32 sectors per track, and data of 512 bytes (byte) is recorded per sector. The disc 1 is provided with a basic data area, a replacement area, and a map area as shown in FIG. The basic data area is an area in which data to be recorded is written, and the replacement area has a replacement sector in which data to be recorded is written when a defective sector occurs in the basic data area. When a defective sector (any one of sectors 0 to 31) occurs in the basic data area during recording, the data is written to an alternate area of tracks N + 1 to N + P different from tracks 0 to N of the basic data area. The map area has an address correspondence table in which replacement information indicating a correspondence relationship between addresses of defective sectors and their replacement sectors is recorded. When data is written to the disk 1 at the time of data recording, the data is read out immediately and is not reproduced correctly. When it is detected that the sector is a defective sector, data to be recorded in the defective sector is recorded in a replacement sector, and the sector address of the defective sector is recorded. And the sector address of the replacement sector are paired and recorded in the address correspondence table. At the time of reproduction, the replacement information in the address correspondence table is read first, and any sector in the basic data area is defective and the address of the replacement sector can be known.

In some disks, first and second alternate areas are provided as alternate areas. If a defective sector occurs in the basic data area during recording, the defective area is recorded in the first alternate area on the same track as that track. When the first replacement area is already used or when the first replacement area has a defect, there is a case where data is written in the second replacement area on a track different from the track in the basic data area.

Further, the rotation speed of the disk 1 is 2400 rp
m and 25 msec per rotation. The data transfer rate to the host computer 11 as an apparatus is 20
00Kbyte / sec, and the transfer speed when transferring data simultaneously with reading data from the disk 1 is 1000Kbyt
e / sec. Next, the buffering operation of each system in the disk drive device having such a configuration will be described. For the sake of explanation, it is assumed that data of 128 Kbytes from the first sector to the 256th sector is transferred from the disk 1 as an example, and it is assumed that data is read from the basic data area of the disk 1 where there are no defective sectors. It is assumed that the read start sector and the specified number of sectors from the read start sector are supplied to the control circuit 8 as data.

In the operation of the single buffering system, as shown in FIG. 3, the control circuit 8 performs a seek operation for moving the information reading point of the pickup 4 to the starting point of the reading start sector (first sector). The data reading operation of the capacity of, ie, 64 Kbytes, is started (step S1). Then, it is determined whether or not reading of the specified number of sectors has been completed (step S2). If the number from the reading start sector to the current sector actually read has not reached the designated sector number, it is determined whether or not the buffer RAM 7 has been filled with the read data (step S).
3). Since the data of the full capacity of the buffer RAM 7 corresponds to data of four tracks, it takes 100 msec.

If data of 64 Kbytes has not been read from the disk 1, the process returns to step S2. If data of 64 Kbytes has been read from the disk 1, the capacity of the buffer RAM 7 becomes full. Is determined (step S
4). Since we are reading from an area with no defective sectors,
An instruction is issued to transfer the data held in the buffer RAM 7 to the host computer 11 (step S5). 64Kb
The time required to transfer yte's worth of data to the host computer 11 is 32 msec.

The host computer 1 in step S5
After the transfer to the host computer 11, it is determined whether or not the data of the designated number of sectors has been transferred to the host computer 11 (step S6). If data of the specified number of sectors has not been transferred to the host computer 11, after waiting for a predetermined time,
The data reading operation for the next 64 Kbytes is started (step S7), and the process returns to step S2. When the data of the specified number of sectors has been transferred to the host computer 11, the present routine ends.

For this operation, in the single buffering system, as shown in FIG. 4, the operation time of reading data of 64 Kbytes from the disk 1 and holding it in the buffer RAM 7 by executing the step S1 of the control circuit 8 is 100 msec. is there. Immediately after the data is held in the buffer RAM 7, execution of step S5 causes the buffer RAM 7
The operation time for transferring 64 Kbytes of data held in the host computer 11 to the host computer 11 is 32 msec. During the transfer period, the disk 1 is rotating, and the reading is stopped.
The disk 1 has to make two revolutions. Therefore, after reading the first 64 Kbytes of data, the next 64 Kbytes
50 seconds including the standby state before cueing for data reading
Requires msec. The operation time of reading the next 64 Kbytes of data from the disk 1 and holding it in the buffer RAM 7 by executing the step S7 of the control circuit 8 is 100 msec.
The operation time for transferring 64 Kbytes of data held in the host computer 11 to the host computer 11 is 32 msec. Therefore,
The total time required to read 128 Kbytes of data from an area of the disk 1 having no defective sectors and transfer it to the host computer 11 by the single buffering method is 282 msec in total. In FIG. 4, the unit of byte is omitted, and the same applies to other timing charts described below.

In the operation of the double buffering system, as shown in FIG. 5, the control circuit 8 moves the information reading point of the pickup 4 to the starting point of the reading start sector, and then performs the data reading operation of the designated number of sectors, ie, 128 Kbytes. It is started (step S21). Then, it is determined whether or not reading of the specified number of sectors has been completed (step S22).
If the number from the read start sector to the current sector actually read has not reached the designated sector number, the buffer RAM
It is determined whether or not data having a half capacity (32 Kbytes) of 7 has been read (step S23). Buffer RAM7
Since the data of half the capacity of the data corresponds to the data of two tracks, it takes 50 msec.

If data of 32 Kbytes has not been read from the disk 1, the process returns to step S22. If data of 32 Kbytes has been read from the disk 1, it is determined whether or not there is a defective sector in the read sector (step S22). S24). Since the data is read from the area having no defective sector, the transfer of the data held in the buffer RAM 7 to the host computer 11 is instructed (step S25). The time required to transfer 32 Kbytes of data to the host computer 11 is 16 msec.

After the transfer to the host computer 11 in step S25, it is determined whether or not data of the specified number of sectors has been transferred to the host computer 11 (step S26). If the data for the specified number of sectors has not been transferred to the host computer 11, the process immediately returns to step S22. When the data of the specified number of sectors has been transferred to the host computer 11, the present routine ends.

Therefore, in the double buffering system, as shown in FIG.
, The data of 128 Kbytes is continuously read from the disk 1 and stored in the buffer RAM 7, so that the operation time is 200 msec. Buffer RAM
Every time 32 Kbytes of data are held in the memory 7, the execution of step S25 immediately transfers the 32 Kbytes of data held in the buffer RAM 7 to the host computer 11, and the operation time is 16 msec. Therefore, since only the transfer of the last 32 Kbytes of data to the host computer 11 is performed after reading the data from the disk 1, the 128 Kbytes of data is read from the area of the disk 1 having no defective sectors by the double buffering method. The time required to transfer the data to the computer 11 is 216 msec in total.

Next, in the operation of the ring buffering system, as shown in FIG.
After moving the information reading point to the starting point of the reading start sector,
The data reading operation of the designated number of sectors, that is, 128 Kbytes is started (step S41). Then, it is determined whether or not the next sector is a defective sector (step S4).
2). Since we are reading from an area with no defective sectors,
Proceeding to step S43, it is determined whether or not data of one sector or more is newly held in the buffer RAM 7 (step S43). If data of one sector has not been read from the disk 1, the process returns to step S42. If data of one sector has been read from the disk 1, the data of one sector held in the buffer RAM 7 is sent to the host computer 11. (Step S4)
4). After the transfer to the host computer 11 in step S44, it is determined whether or not data of the specified number of sectors has been transferred to the host computer 11 (step S4).
5). If data of the specified number of sectors has not been transferred to the host computer 11, step S42 is immediately executed.
Return to When the data of the specified number of sectors has been transferred to the host computer 11, the present routine ends.

In the ring buffering method, as shown in FIG. 8, the control circuit 8 executes step S41 to continuously read data of 128 Kbytes from the disk 1 and hold the data in the buffer RAM 7, so that the operation time is as follows. 200 msec. Every time data of one sector is newly held in the buffer RAM 7, the data of one sector held in the buffer RAM 7 is immediately transferred to the host computer 11 by executing step S44,
The transfer operation time for one sector is 0.5 msec. Therefore, since only the transfer of the last one sector of data to the host computer 11 is performed after the data is read from the disk 1, the disk 1 is stored in the ring buffering system.
The total time required to read 128 Kbytes of data from the area having no defective sector and transfer it to the host computer 11 is 200.5 msec.

In addition, in actuality, even in each buffering method, a transfer time for one sector is further required for error correction, but is omitted. Thus, disk 1
When a defective sector is not included in the sector in the basic data area to be read from the data, the data transfer is performed in the order of the ring buffering method, the double buffering method, and the single buffering method as described above. However, when a sector to be read from the disk 1 includes a defective sector, it is not always faster in this order.

For example, when there is a defective sector on each track in the radial direction due to a scratch on the disk 1,
A defective sector occurs every Kbyte. That is, data to be recorded in the defective sector is recorded in the replacement sector. 128 Kb to transfer to host computer 11 as above
The operation of each buffering method in the case where four defective sectors A to D exist one for every 16 Kbytes as shown in FIG. 9 in the basic data area for reading data for yte will be described. In the replacement area, replacement sectors A ′ to D ′ corresponding to defective sectors A to D are formed, and data of an address correspondence table of the map area is read in advance and stored in a RAM (not shown) in the control circuit 8. Because it is remembered,
It is assumed that the read sector is a defective sector from the data in the address correspondence table.

In the operation of the single buffering system, as shown in FIG. 3, the control circuit 8 determines in step S3 that 64 Kbytes of data have been read from the disk 1, and then determines in step S4 the defective sector that has been read. Is determined. If there is a defective sector, a seek operation for moving the information reading point of the pickup 4 to the replacement area is performed, and then the data of the replacement sector corresponding to the defective sector is read and stored in the buffer RAM 7 (step S8). The data holding in the buffer RAM 7 is performed at the buffer holding position corresponding to the defective sector. After the execution of step S8, it is determined whether or not data of the specified number of sectors has been read (step S8).
9). If the data of the designated number of sectors has not been read, a command to transfer the data held in the buffer RAM 7 to the host computer 11 is issued, and the information reading point of the pickup 4 is moved to the start point of the sector to be read next ( Step S10). Then the buffer RAM
The data reading operation for the capacity of 7, that is, 64 Kbytes is started (step S11), and the process returns to step S2.

When data of the specified number of sectors has been read in step S2,
When it is determined that the data of 256 sectors has been read from step S4 and the process proceeds from step S4 to step S8, the information reading point of the pickup 4 is moved to the replacement area, and each data of the replacement sector corresponding to the defective sector is read. Can be After execution of step S8, the process moves from step S9 to step S5.

Therefore, in the single buffering system, as shown in FIG.
The operation time for reading 64 Kbytes of data from the disk 1 and holding it in the buffer RAM 7 by executing
00 msec. Subsequently, by executing step S8, the seek time for the information reading point of the pickup 4 to move to the replacement area is 50 msec, and the time for reading the data of the replacement sector A 'corresponding to the defective sector A is 0.8 msec. After that, the next 64 Kb of the basic data area
The seek time to move to the starting point for reading data of yte is 50 msec. During this seek time, 64 stored in the buffer RAM 7 by the execution of step S10.
Kbytes of data are transferred to the host computer 11, but the operation time is 32 msec, which is shorter than the seek time. After the seek operation to the basic data area is completed, the control circuit 8 executes step S11 to execute the next 6
The operation time for reading 4 Kbytes of data and storing it in the buffer RAM 7 is 100 msec, and
8, the time for seeking the replacement area is 50 msec, and the replacement sector B corresponding to the three defective sectors B to D is used.
The time to read the data of '-D' is 2.3 msec.
The operation time for transferring 64 Kbytes of data held in the buffer RAM 7 to the host computer 11 is 32 msec.
It is. Therefore, the total time required to read 128 Kbytes of data from the area where the four defective sectors of the disk 1 are located and transfer it to the host computer 11 by the single buffering method is 385.1 msec in total.

In the operation of the double buffering method, as shown in FIG. 5, the control circuit 8 determines in step S23 that data of half the capacity of the buffer RAM 7 has been read, and then in step S24 a defect in the sector read. It is determined whether or not there is a sector. If there is a defective sector, the data reading operation from the disk 1 is stopped (step S27), the information reading point of the pickup 4 is moved to the replacement area, and the data of the replacement sector corresponding to the defective sector is read. The data is stored in the buffer RAM 7 (step S28). After the execution of step S28, it is determined whether or not data of the specified number of sectors has been read (step S29). If the data of the designated number of sectors has not been read, a command to transfer the data held in the buffer RAM 7 to the host computer 11 is issued, and the information reading point of the pickup 4 is moved to the start point of the sector to be read next ( Step S30). Then
The operation of reading the remaining data from the disk 1 is started (step S31), and the process returns to step S22.

When data of the designated number of sectors has been read in step S22, that is, when it is determined that data of 256 sectors has been read from the disk 1, if the process proceeds from step S24 to step S27, the pickup 4 Is moved to the replacement area, and each data of the replacement sector corresponding to the defective sector is read. After execution of step S28, the process moves from step S29 to step S25, and the data held in the buffer RAM 7 is transferred to the host computer 11.

Therefore, in the double buffering method, as shown in FIG.
By executing step 1, 64 Kbytes of data are continuously read from the disk 1 and stored in the buffer RAM 7, so that the operation time is 100 msec. Buffer RAM
When the first 32 Kbytes of data are stored in step 7, since no defective sector is included therein, step S2 is immediately executed.
5, the first 3 stored in the buffer RAM 7
Data of 2 Kbytes is transferred to the host computer 11. Since the transfer operation time is 16 msec, it is included in the period for reading the second 32 Kbytes of data from the disk 1. After reading the second 32 Kbytes of data including the defective sector A, the data reading from the disk 1 is stopped, and the seek time to the replacement area is 50 msec by executing step S28. The time for reading the data of A 'is 0.8 msec.

Thereafter, the seek time for moving from the replacement area to the starting point for reading the third 32 Kbytes of data in the basic data area is 50 msec. During this seek time, the second 32 Kbytes of data held in the buffer RAM 7 are transferred to the host computer 11 by executing step S30, but the operation time is 16 msec, which is shorter than the seek time. After the seek operation to the basic data area is completed, the control circuit 8 executes step S31 to read the third 32 Kbytes of data including the defective sectors B and C from the disk 1 and store the data in the buffer RAM 7 in 50 msec. Yes, the seek time to the replacement area is 50 msec by executing step S8 again, and the time to read data of the replacement sectors B ′ and C ′ corresponding to the two defective sectors B and C is 1.6 msec. The same seek operation is performed for the fourth 32 Kbytes of data including the defective sector D, and only the transfer of the fourth 32 Kbytes of data to the host computer 11 is performed after the data is read from the disk 1. 128Kbyt from the area where the defective sector of the disk 1 exists by the double buffering
The total time required to read e minutes of data and transfer it to the host computer 11 is 469.2 msec.

Next, in the operation of the ring buffering system, as shown in FIG.
It is determined whether or not the read sector has a defective sector. If there is a defective sector, the reading operation is stopped (step S46), and the 1
A command to transfer the data of the sector to the host computer 11 is issued (step S47), the information reading point of the pickup 4 is moved to the replacement area, and then the data of the replacement sector corresponding to the defective sector is read and stored in the buffer RAM 7. It is held (step S48). After the execution of step S48, it is determined whether or not data of the specified number of sectors has been read (step S49). If the data of the specified number of sectors has not been read, the transfer of the data newly held in the buffer RAM 7 to the host computer 11 is commanded, and the data is moved to the start point of the next sector to be read (step S50). Next, the operation of reading the remaining data from the disk 1 is started (step S5).
1) Return to step S42.

If it is determined in step S49 that data for the specified number of sectors has been read, that is, if it is determined that data for 256 sectors has been read from the disk 1, the process proceeds to step S43. Therefore, in the ring buffering method, as shown in FIG. 12, first, the control circuit 8 executes step S41 to continuously read 56 Kbytes of data in an area having no defective sector from the disk 1 and hold the data in the buffer RAM 7. Therefore, the operation time is 87.5 msec. Since the next sector is defective sector A, the reading is stopped in step S46. Every time data of one sector is newly stored in the buffer RAM 7, the data of one sector stored in the buffer RAM 7 is immediately transferred to the host computer 11 by executing step S44, and the transfer operation time of one sector is performed. Is 0.5 msec. After the reading is stopped, in step S47, the data of the sector one sector before the defective sector A is transferred to the host computer 11, and the transfer operation time for one sector is 0.5 msec.

Next, by executing step S48, the seek time to the replacement area is 50 msec, and the time to read the data of the replacement sector A 'corresponding to the defective sector A is 0.
8 msec. Thereafter, the seek time for moving from the replacement area to the start point of the sector next to the defective sector A in the basic data area by executing step S50 is 50 msec. When returning to the start point of the sector next to the defective sector A in the basic data area, by executing step S51, the data of 15.5 Kbytes up to the sector immediately before the defective sector B is continuously read and stored in the buffer RAM 7. The operation time is 24.2 msec. Then, steps S47 and S4
8. It takes 101.3 msec to read the replacement sector B 'for the defective sector B by the operations of S50.

Since the same operation as described above is performed for defective sectors C and D, 128 Kbytes of data is read from the area where the defective sector of the disk 1 is located by the ring buffering method and transferred to the host computer 11. The required time is a total of 603 msec.

[0030]

As described above, if a defective sector exists in a sector in the basic data area of the disk to be transferred, in the ring buffering system, the pickup 4 is transferred to a corresponding alternate sector for each defective sector. Since the seek operation for moving the information reading point is performed, there is a disadvantage that more time is required for data transfer than in the single buffering method or the double buffering method.

It is an object of the present invention to provide a buffering method for completing data transfer in a short time even if a defective sector exists in a sector in a basic data area of a disk to be transferred.

[0032]

A buffering method according to the present invention comprises: a basic data area in which data is recorded in sector units; a replacement area in which data to be recorded in a defective sector of the basic data area is recorded; Buffering for transferring data read from a disk having a data area and a map area in which replacement information indicating the correspondence between sectors of the replacement area is recorded as continuous data to an external device via a buffer memory The method is characterized in that replacement information is read at the time of data transfer, and one of a plurality of different predetermined buffering methods is selectively used based on the read replacement information. .

[0033]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a buffering method according to the present invention.
This is applied to the disk drive shown in FIG. Next, the buffering operation when data from the sector address S to the sector address E in the basic data area of the disk 1 is transferred to the host computer 11 will be described according to the operation of the control circuit 8.

The control circuit 8, as shown in FIG.
The replacement information from the address S to the address E of the disk 1 is read from the address correspondence table in the map area (step S61), and the address S is set to the pointer P (step S62). Next, the pointer P moves to the address E
Is determined (step S63). P ≠ E
In this case, it is determined whether or not a defective sector exists from the address indicated by the pointer P to the address E (step S64).

From the address indicated by the pointer P to the address E
If there is no defective sector before, the data of each sector from the address indicated by the pointer P to the address E is transferred by the ring buffering method (step S65). The data transfer of the ring buffering method is obtained by executing the operation shown in FIG. In this case, step S45
Then, it may be determined that the designated sector number is E−S + 1. After the execution of step S65, the pointer P is increased by the number of transferred sector addresses (step S66).
Move to step S63. When step S63 is executed after execution of step S65, P = E, so this routine ends.

If it is determined in step S64 that there is a defective sector from the address indicated by the pointer P to the address E, the control circuit 8 determines from the address indicated by the pointer P the address corresponding to the capacity of the buffer RAM 7 as shown in FIG. It is determined whether or not there is a defective sector before (step S67). If there is no defective sector from the address indicated by the pointer P to the address corresponding to the capacity of the buffer RAM 7, the data of the sector from the address indicated by the pointer P to the sector address immediately before the sector address where the defective sector exists is stored in a ring buffering system. (Step S68). The data transfer of the ring buffering method may be performed by performing the operation shown in FIG. 7 as in step S65. Since the control circuit 8 reads the replacement information from the address correspondence table in the map area,
Assuming that the address of the defective sector is D, step S4
In S49, it may be determined that the designated sector number is DS + 1. After execution of step S68, the control circuit 8
The process moves to execution of step S66.

If it is determined in step S67 that there is no defective sector between the address indicated by the pointer P and the address corresponding to the capacity of the buffer RAM 7, the range from the address indicated by the pointer P to the address corresponding to the capacity of the buffer RAM 7 is set. It is determined whether only one defective sector exists (step S69). When the control circuit 8 determines that only one defective sector exists from the address indicated by the pointer P to the address corresponding to the capacity of the buffer RAM 7 from the address correspondence table in the map area, the sector at the address indicated by the pointer P is a defective sector. It is determined whether or not there is (step S70). Pointer P
In the case where the sector of the address indicated by, that is, the sector of the first address is a defective sector, the control circuit 8 moves the information reading point of the pickup 4 to the replacement area, and then reads the data of the replacement sector corresponding to the defective sector. Then, the data is stored in the buffer RAM 7 (step S71), and the stored data is transferred to the host computer 11 (step S72). Thereafter, the process proceeds to step S66.

If the sector at the address indicated by the pointer P is not a defective sector in step S70, it is determined whether the data capacity from the address indicated by the pointer P to the address E is within the capacity of the buffer RAM 7 (step S73). Since the capacity from the address indicated by the pointer P to the address E can be obtained from the number of sectors, the buffer RAM
7 can be determined. The capacity from the address indicated by the pointer P to the address E is the buffer RAM.
If the capacity is larger than 7, the process proceeds to step S68 to transfer data from the address indicated by the pointer P to the sector address immediately before the sector address where the defective sector exists, by the ring buffering method.

On the other hand, when the capacity from the address indicated by the pointer P to the address E is within the capacity of the buffer RAM 7, the data of the sector from the address indicated by the pointer P to the address E is transferred by the single buffering method (step S74). . The data transfer of the single buffering method is obtained by executing the operation shown in FIG.

If it is determined in step S69 that only one defective sector exists in the range from the address indicated by the pointer P to the address corresponding to the capacity of the buffer RAM 7, there are two or more defective sectors in that range. Therefore, it is determined whether or not the capacity from the address indicated by the pointer P to the address E is within the capacity of the buffer RAM 7 (step S75). This operation is the same as step S73. If the capacity from the address indicated by the pointer P to the address E is larger than the capacity of the buffer RAM 7, the data of the sector from the address indicated by the pointer P to the address corresponding to the capacity of the buffer RAM 7 is transferred by the single buffering method (step S76). ). The data transfer of the single buffering system is also obtained by executing the operation shown in FIG. If the capacity from the address indicated by the pointer P to the address E is within the capacity of the buffer RAM 7, the process proceeds to step S74 to transfer the data of the sector from the address indicated by the pointer P to the address E by the single buffering method. After execution of step S74 or S76, the control circuit 8 proceeds to execution of step S66.

According to the buffering method according to the present invention, as shown in FIG. 9, four defective sectors A to D exist in 256 sectors (128 Kbytes) of the basic data area to be transferred, one for every 16 Kbytes. In this case, since the defective sector A is in the 113th sector and exists within the capacity (128 sectors) of the buffer RAM 7 and there is no defective sector in 56 Kbytes from the first sector to the 112nd sector, step S68 is executed. You. As a result, as shown in FIG. 15, 56 Kbytes of data from the first sector to the 112th sector are continuously read from the disk 1 and stored in the buffer RAM 7, so that the operation time is 87.5 msec. Since the next 113th sector is defective sector A, the reading is stopped in step S46. After the reading is stopped, the data of the 112th sector one sector before the defective sector A is transferred to the host computer 11 in step S47, and the transfer operation time for one sector is 0.5 msec. Step S4
During the period (25 msec) during which the disk 1 makes at least one rotation due to the stop of reading by No. 6, the next 113rd sector does not become the information reading point of the pickup 4.

Next, by executing step S66, the pointer P indicates the 113th sector of the defective sector. Since there are four defective sectors A to D from the 113th sector indicated by the pointer P to the 240th sector corresponding to the capacity of the buffer RAM 7, single buffering is performed for the 113th to 240th sectors by executing step S76. The data is transferred by the method. Therefore, by executing step S1, 64 Kbytes of data from sector 113 to sector 240 of disk 1 are read and buffer RA is read.
The operation time held in M7 is 100 msec. Subsequently, the time for seeking the replacement area by executing step S8 is 50 msec, and the time for reading the data of the replacement sectors A ′ to D ′ corresponding to the defective sectors A to D is 3.1 ms.
ec. Thereafter, the seek time from the replacement area to the starting point for reading the next 64 Kbytes of data in the basic data area is 50 msec. During this seek time, the data of 64 Kbytes held in the buffer RAM 7 is transferred to the host computer 11 by executing step S10.

After the seek operation to the basic data area is completed,
By executing step S66, the pointer P indicates the 241st sector of the defective sector. Since there is no defective sector from the 241st sector to the 256th sector of the address E, step S65 is executed. Therefore, since 8 Kbytes of data from the 241st sector to the 256th sector are continuously read from the disk 1 and stored in the buffer RAM 7 by the ring buffering method, the operation time is 12.5 msec. Only the transfer of the last 256 sector data to the host computer 11 is performed after reading the data from the disk 1, and the operation time is 0.5 msec. Therefore, four defective sectors A to D
The total time required to read 128 Kbytes of data, one for every 16 Kbytes, and transfer it to the host computer 11 is 328.6 msec.
This can be shortened compared to the conventional single system shown in FIG.

Next, the first data in the basic data area of the disk 1
When data of 128 Kbytes from the sector to the 256th sector is read and transferred to the host computer 11, when one defective sector F exists in the 161st sector as shown in FIG. The operation of the ring method will be described. The control circuit 8 executes step S68 to continuously read 80 Kbytes of data from the first sector to the 160th sector and store them in the buffer RAM 7 by the ring buffering method as shown in FIG. 0.5
The data is transferred to the host computer 11 with a delay of msec. This operation time is 125 msec + 0.5 msec. Next, since the seek operation to the replacement area is performed by executing step S71, 50 msec is required, and the data of the replacement sector F ′ corresponding to the defective sector F is read, and the data is read by 0.8 msec.
msec is required. Thereafter, by performing step S65, a seek operation is performed in which the information reading point of the pickup 4 moves from the replacement area to the start point of the 162nd sector next to the defective sector F in the basic data area by the ring buffering method. 50 msec. 47.5 Kbytes of data from the 162nd sector to the 256th sector are continuously read and held in the buffer RAM 7,
The held data is transferred to the host computer 11 with a delay of 0.5 msec. This operation time is 74.2 msec + 0.
5 msec. Therefore, the total time required to read 128 Kbytes of data in which one defective sector F exists and transfer the data to the host computer 11 is 301 msec in total. This is exactly the same as the operation of the ring buffering method.

FIG. 18 shows the operation and the lapse of time when the 128-Kbyte data shown in FIG. 16 is transferred by the single buffering method, and FIG. 19 shows the operation and the lapse of time when the data is transferred by the double buffering method. The time required to read and transfer data from the disk 1 is 332.8 ms in total in the single buffering method.
ec, total 316.8 msec for double buffering method
It is.

Next, when reading 64 Kbytes of data from the first sector to the 128th sector of the basic data area of the disk 1 and transferring the data to the host computer 11, one byte within the range of 64 Kbytes as shown in FIG. The operation of the buffering method according to the present invention when one defective sector G exists in the 33rd sector will be described.

The control circuit 8 executes step S74 to read 64 Kbytes of data from the first sector to the 128th sector by the single buffering method as shown in FIG. 21, and the read time is 100 msec. Subsequently, a seek operation to the alternate area is performed, and the seek time is 50 msec. The data of the replacement sector G 'corresponding to the defective sector G is read, and the read time is 0.8
msec. After that, the 6 stored in the buffer RAM 7
4 Kbytes of data are transferred to the host computer 11, and the transfer operation time is 32 msec. Therefore, the total time required to read 64 Kbytes of data in which one defective sector G exists and transfer it to the host computer 11 is 182.8 msec in total. This is exactly the same as the operation of the single buffering method.

FIG. 22 shows the operation and time lapse when transferring 64 Kbytes of data shown in FIG. 20 by the double buffering method, and FIG. 23 shows the operation and time lapse when the data is transferred by the ring buffering method.
The time required to read and transfer data from the disk 1 is 216.8 msec in total in the double buffering system and 201 msec in total in the ring buffering system.

In the above-described embodiment, a method in which the single buffering method and the ring buffering method are mixed is described. However, a method in which the double buffering method and the ring buffering method are mixed may be used.
In this case, the steps S74 and S76 shown in FIG. 14 may be performed by the control circuit 8 using the double buffering method. Further, it is apparent that a method combining the single buffering method and the double buffering method or a method combining the single buffering method, the double buffering method and the ring buffering method may be used.

In the above embodiment, the disk 1 is divided into 32 sectors per track and 512 bytes of data are recorded per sector.
Is 64 Kbytes, but is not limited to these values. Further, it may be determined whether to use the single buffering method or the double buffering method according to the capacity of the buffer RAM 7.

[0051]

As described above, in the buffering method of the present invention, one of a plurality of different predetermined buffering methods is selected based on the replacement information read from the replacement area of the disk. The data is read by the selected buffering method and transferred to an external device. Therefore, when a defective sector is present in a sector in the basic data area of the disk to be transferred, an appropriate buffering method is used according to replacement information such as the number and position of the defective sector. Data transfer can be completed in time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a disk drive device to which a buffering method of the present invention is applied.

FIG. 2 is a diagram showing a configuration of each area of a disk.

FIG. 3 is a flowchart showing the operation of the single buffering method.

FIG. 4 is a diagram showing operation timing of a single buffering method.

FIG. 5 is a flowchart showing the operation of the double buffering method.

FIG. 6 is a diagram showing operation timing of the double buffering method.

FIG. 7 is a flowchart showing the operation of the ring buffering method.

FIG. 8 is a diagram showing operation timing of the ring buffering method.

FIG. 9 is a diagram showing positions when four defective sectors exist in a basic data area.

FIG. 10 is a diagram showing operation timing of the single buffering method.

FIG. 11 is a diagram showing operation timing of the double buffering method.

FIG. 12 is a diagram showing operation timing of the ring buffering method.

FIG. 13 is a flowchart showing the operation of the control circuit when the buffering method according to the present invention is applied.

FIG. 14 is a flowchart showing an operation of a continuation of the operation of the control circuit in FIG. 13;

FIG. 15 is a diagram showing operation timing when the buffering method according to the present invention is applied.

FIG. 16 is a diagram showing a position when one defective sector exists in a basic data area.

FIG. 17 is a diagram showing operation timing when the buffering method according to the present invention is applied.

FIG. 18 is a diagram showing operation timing of the single buffering method.

FIG. 19 is a diagram showing operation timing of the double buffering method.

FIG. 20 is a diagram showing a position when one defective sector exists in a basic data area.

FIG. 21 is a diagram showing operation timing when the buffering method according to the present invention is applied.

FIG. 22 is a diagram showing operation timing of the double buffering method.

FIG. 23 is a diagram showing operation timing of the ring buffering method.

[Explanation of Signs of Main Parts]

 Reference Signs List 1 disc 2 turntable 3 spindle motor 4 optical pickup 5 modulation / demodulation circuit 6 error correction circuit 7 buffer RAM 8 control circuit 9 ROM 10 input / output port 11 host computer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 20/10 G06F 3/06

Claims (3)

(57) [Claims] 1. A correspondence relationship between a basic data area in which data is recorded in sector units, a spare area in which data to be recorded in a defective sector of the basic data area is recorded, and each sector in the basic data area and the spare area. A buffering method for transferring data read from a disk having a map area in which replacement information indicating the replacement is recorded as continuous data to an external device via a buffer memory, wherein said replacement is performed during data transfer. A buffering method comprising: reading information; and selectively using one of a plurality of different predetermined buffering methods based on the read replacement information. 2. The buffering method according to claim 1, wherein the plurality of different predetermined buffering schemes are a single buffering scheme and a ring buffering scheme. 3. The buffering method according to claim 1, wherein the plurality of different predetermined buffering methods are a double buffering method and a ring buffering method.