JP2000105672A - Storage device controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a misread due to an illegal positioning by logically disabling data to be reproduced when a track other than a target track is accessed. SOLUTION: To the storage device controller 101, a data bus 108 administering a data communication with a SCSI I/F 102 and a data bus 109 which administers a data communication with a storage device 103 are connected. The controller 101 which controls this storage device 103 is provided with a function of recording in the storage device data to be recorded in the storage device 103 after EX-ORing it with scramble data comprising the track number of a target physical track to be accessed and a head number. Further the controller 101 is given a function of host transfer of data reproduced from the storage device 103 after EX-ORing it with the scramble data comprising the track number of the target physical track to be accessed and the head number.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage device having a mechanical positioning means, and more particularly to a technique applicable to a means for preventing a misread due to a positioning error.

[0002]

2. Description of the Related Art In recent years, the size of a storage element per bit has been reduced with the increase in capacity of a storage device. The increase in recording density is generally expressed by two-dimensional parameters,
For example, in a storage device having a circular medium typified by a magnetic disk device, the recording density is a track density in the radial direction (Track per Inch: TPI) and a bit density in the circumferential direction (Bit per Inch: BPI). Is expressed.

In such a storage device, a track is generally accessed using a mechanical means (an actuator or the like), but the operating speed of the mechanical system is one unit (hereinafter referred to as a sector) of a data string in a circumferential direction. Therefore, when the TPI increases, a data string of an adjacent track is erroneously read when the TPI increases.

Conventionally, in order to solve such a problem, an identification number is added to a case data sector, and the number (Logical) is added.
Block Address (hereinafter referred to as LBA) is written at the head of the sector, and the LBA read during data reproduction is checked to prevent misread. Also, as described in US Pat. No. 5,640,286, L
L not different from LBA accessed by embedding in redundant information such as ECC without writing BA directly on the medium.
When the BA data is read, a method has been adopted in which the ECC pattern becomes a completely different data string, and as a result, the data cannot be read.

On the other hand, a storage device has a sector replacement logic for moving a sector to a physically different location when the reading / writing of the sector is hindered by a flaw or defect on the medium. Here, since the LBA has a property associated with the sector, even if the sector is moved to another location by the replacement logic, the LBA does not change before and after the replacement.
Therefore, when a certain sector is replaced, the same LBA
Will exist in two places.

If such a sector is located on an adjacent track, it goes without saying that a misread is induced for the above-mentioned reason. There is no means for checking the error in the misread that occurred in such a process, and when viewed from the host controller, there has been a problem that the recorded data is garbled.

[0007]

In the above situation, it has been an object to develop means for preventing misreading when improper positioning occurs in a storage device.

An object of the present invention is to pay attention to the fact that misreads are likely to occur due to improper track positioning, and logically disable data reproduction when a track other than the target track to be accessed is accessed. This is to provide means for preventing misread.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0010]

The following is a brief description of an outline of typical inventions disclosed in the present subject matter.

That is, according to the present invention, a controller for controlling a storage device is provided with at least one of a part of data recorded in the storage device and at least one of a track number and a head number of a target physical track to be accessed.
EX-OR with byte scrambled data before recording in the storage device, and a part or all of the data reproduced from the storage device is composed of the track number and head number of the target physical track to be accessed By providing a function of performing a host transfer after EX-ORing with at least one byte of descrambling data, it is possible to prevent a data misread when an improper positioning occurs.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a magnetic disk drive according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a data recording / reproducing circuit in a storage device controller, including a function devised by the present invention. The storage device controller 101 has a SCSI I /
A data bus 108 that controls data communication with the F102 and a data bus 109 that controls data communication with the storage device 103 are connected. Communication of commands and status signals from the SCSI I / F 102 is performed via a command bus 116.

On the other hand, exchange of commands with the storage device 103 is performed using a command bus 110. SCSI
The command from the I / F 102 is analyzed by the MPU 107, and as a result, what kind of operation is to be performed on the storage device 103 is converted into a command corresponding to the storage device 103 and communicated.

Next, the flow of the data transferred from the SCSI I / F 102 in the storage device controller will be described as follows. First, when data is recorded, the location of the data is indicated by the command bus 116, and at the same time, the data is transferred via the data bus 108. The transferred data is input to the selector 111 and the ECC generation circuit 112. The ECC code generated by the ECC generation circuit 112 is added to the end of the data by the selector 111 and transferred.

Here, the scramble circuit 104 is a circuit that performs an EX-OR of the physical location information (physical track and head) of the data transferred from the selector 111 and the data analyzed by the MPU 107, and this processing is performed. After that, the data is transferred to the storage device 103 via the buffer 113.

Next, the case of reproducing data will be described. The data reproduced from the storage device is transmitted to the data bus 10
9. Descramble circuit 10 via buffer 114
5 is input. A descrambling circuit 105 is a circuit that performs an inverse conversion of the scramble circuit 104, and performs an EX-OR operation on the reproduced data and physical location information (physical track and head) in which the reproduced data is recorded.
After this processing is performed, the data is transferred to the ECC check circuit 115. Here, an ECC check of the data is performed. If there is no error in the data, the data is transferred to the SCSI I / F 102 via the data bus 108. If there is an error in the data, the next processing is instructed by the MPU 107.

[0018]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It looks like this:

FIG. 2 shows how data is scrambled / descrambled in the present invention. Gates 201, 202
Are scramble / descramble circuits for recording and reproduction, respectively. Here, b7-
The lower three bits of the track number when the track number and the head number are expressed in binary numbers are represented by b
7, b6, b5, the lower 5 bits of the head number are b4, b
3, b2, b1, and b0. As an example, if the track number is 9 and the head number is 5, the scramble data 204 is (00100101) as shown in the figure.

Here, data 203 from the host computer
Is assumed to be 1-byte repetition data for simplicity. Here, it is assumed that the data is all-bit 0 data. When the data 203 is written to the storage device, as shown in FIG. 2, the scramble data 204 and the data 203 from the host computer are EX-ORed by the gate 201, and the data 207 written to the storage device is (00100101). Become.

Similarly, when data 205 is recorded on track number 8 and head number 5, the scrambled data 206 is (00000101) as shown in FIG. 2, so that the data 208 actually written to the storage device is (0000).
0101). Here, consider a case where data of a track with track number 8 and head number 5 is read from the storage device.

If the data of track number 9 is erroneously read due to incorrect positioning of the storage device, the read data 209 is (00100
101). However, since the storage controller has instructed the positioning to the track number 8, the storage device controller descrambles the data to the track number 8, ie, (0
0000101). Therefore,
The data 211 read by the controller is (0
0100000).

Here, an ECC check is performed.
The CC data is created for the pattern (00000000) of the data 205 recorded on the track number 8 and the head number 5 and is added to the end of the data, and the ECC data itself is recorded by descrambling. Since a pattern different from the above is read, all data bytes in this sector become errors, ECC correction becomes impossible, and appropriate processing such as retry is performed. That is, even when an adjacent track is read out due to incorrect positioning, the data is not transferred to the host computer.

In the selection of scramble data, the lower 3 bits of the track number and the lower 5 bits of the head number are assigned here, but this has a redundancy of 8 tracks for the track and 32 heads for the head. . Therefore, the same scramble data is repeated for every eight tracks for the track. However, since incorrect positioning is likely to occur in a track adjacent to the target track, it can be said that having such a degree of redundancy is sufficient. Of course, it is needless to say that the track / head redundancy can be changed by changing the allocation of the scramble data.

[Brief description of the drawings]

FIG. 1 is a data flow diagram in a storage device controller of the present invention.

FIG. 2 is a diagram showing a format of data scrambling / descrambling.

[Explanation of symbols]

101: Storage device controller, 102: SCSI interface, 103: Storage device, 104: Scramble circuit, 105: Descramble circuit, 106: Register for storing a physical track / head number, 107:
MPU (microprocessor unit), 108 ... data bus (SCSI I / F controller), 109 ...
Data bus (controller⇔storage device), 110 command bus (controller⇔storage device), 111 selector, 112 ECC generation circuit, 113 buffer, 114 buffer, 115 ECC check circuit, 116 command bus (SCSI I / F controller), 201: scramble circuit, 202: descramble circuit, 203: data transferred from SCSI I / F, 204: scramble data for data recorded in track number 9, head number 5, 205
... Data transferred from the SCSI I / F, 206... Scramble data for data recorded on track number 8 and head number 5, 207... Data recorded on track number 9 and head number 5, 208. Data recorded in head number 5, 209... Track number 9, data erroneously reproduced from head number 5,
210: scrambled data for reproducing data from track number 8 and head number 5, 211: data descrambled from erroneously reproduced data.

Claims (6)

[Claims] 1. A storage device controller for controlling a recording / reproducing operation of a storage device, wherein the storage device performs an operation of writing an error correction code (hereinafter, ECC) added to data of one sector to be transferred to the storage device. A function that can scramble the physical track number and head number of the
A storage device controller having a function of descrambling an ECC added to data transferred from the storage device with a physical track number and a head number of the storage device which performs a read operation of the data. 2. The storage device controller has at least one byte of scramble / descramble data comprising a physical track number and a head number of a storage device for recording / reproducing data, and one sector to be transferred to the storage device. EX-OR the ECC data to be added to the data string with the scrambled data and the function to EX-OR the ECC data added to the data string of one sector transferred from the storage device with the descrambled data. The storage device controller according to claim 1. 3. A storage device controller for controlling a recording / reproducing operation of a storage device, wherein at least one byte of sync byte data indicating a head of one sector of data to be transferred to the storage device is written. A function capable of scrambling the physical track number and head number of the storage device, and the physical track number and head number of the storage device performing the read operation of the sync byte data indicating the beginning of the data string of one sector transferred from the storage device And a storage device controller having a function of descrambling. 4. The storage device controller according to claim 1, wherein said storage device controller scrambles / stores at least one byte of a physical track number of a storage device for recording / reproducing data and a head number.
A function of EX-ORing at least one byte of sync byte data indicating the beginning of a data string of one sector to be transferred to the storage device with the descramble data and the scrambled data, and data of one sector transferred from the storage device 4. The storage device controller according to claim 3, wherein the storage device controller has a function of EX-ORing sync byte data indicating a head of a column with the descrambling data. 5. A storage controller for controlling a recording / reproducing operation of a storage device, wherein a data string to be transferred to the storage device can be scrambled with a physical track number and a head number of the storage device performing the data write operation. A storage device controller having a function of descrambling a data string transferred from the storage device with a physical track number and a head number of the storage device performing a read operation of the data. 6. The storage device controller has at least one byte of scramble / descramble data including a physical track number and a head number of a storage device for recording / reproducing data, and a data string to be transferred to the storage device. 6. The storage device controller according to claim 5, which has a function of EX-ORing the data sequence with the scrambled data and a function of EX-ORing the data sequence transferred from the storage device with the descrambled data.