JP2968790B1 - Address conversion method for magnetic disk drive, magnetic disk drive, recording medium recording address conversion program - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To speed up a search for a media defect list when converting a logical address to a physical address. A medium defect list conversion unit (12) subtracts an offset value from a physical address on a medium defect list specified by the offset value, and passes the value to a search unit (21). The search unit 11 specifies the offset value to the medium defect list conversion unit 12 to indicate the offset value.
The physical address on the medium defect list is converted into a virtual logical address by the medium defect list conversion unit 12. Search unit 1
1 performs a search using the specified logical address and the virtual logical address obtained by the medium defect list conversion unit 12.
The search ends when a virtual logical address larger than the logical address appears in the medium defect table. The physical address is obtained by adding the offset value obtained as a result of the search to the logical address.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for converting a logical address into a physical address in a magnetic disk drive which accesses with a logical address and performs medium defect processing.

[0002]

2. Description of the Related Art A conventional method of converting a physical address into a logical address is as follows. If there is no defective sector from the logical address “0” to the target logical address, the logical address matches the physical address. At first,
Assuming that there are no defective sectors up to the target logical address,
The target logical address is set as a temporary physical address (hereinafter, referred to as a temporary physical address). A search is performed for a physical address lower than the temporary physical address in the medium defect list. If there is no defective sector as a result of the search, the temporary physical address becomes a true physical address, and the process ends.
However, if there is a defective sector as a result of the search, the true physical address is a value equal to or greater than the address obtained by adding the number of defective sectors up to the temporary physical address obtained by the search to the temporary physical address. Therefore, for the area larger than the current temporary physical address in the medium defect list, a value obtained by adding the number of defective sectors to the temporary physical address is set as a temporary physical address again, and a search is performed using this temporary physical address. This sequence is repeated, and if no defective sector is detected during the search, the temporary physical address is determined as a true physical address.

[0003]

The above-described conventional address conversion method performs a search on a medium defect list,
Since the search must be repeated until the medium defective sector disappears, the processing speed is slow.

An object of the present invention is to provide an address conversion method and a magnetic disk device for speeding up a search for a medium defect list when converting a logical address to a physical address.

[0005]

In the medium defect list, the position of a medium defective sector on a magnetic disk is registered for each defective sector with a physical address allocated to all sectors including the defective sector in ascending order. Reference is made by an offset value to which an address is assigned in ascending order from 0.

For such a media defect list, the present invention subtracts the offset value from the physical address on the media defect list corresponding to the specified offset value, and the resulting virtual logical address is The physical address is obtained by changing the offset value until it becomes larger than the specified logical address, and adding the final value of the offset value to the logical address.

[0007] By sequentially converting the physical address of the medium defect list into a virtual logical address, the search of the medium defect list can be suppressed to one time.

[0008]

Next, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 1, this embodiment uses an input unit 1 for receiving a logical address from a host, and a medium defect list 100 of a medium defect list storage unit 3 using a logical address obtained by the input unit 1. Search unit that performs a search using the virtual logical address converted by the medium defect list conversion unit 22 and adds the offset value obtained as a result of the search to the logical address as the number of defective sectors to obtain a physical address. 11 and the offset value specified by the search unit 11, the physical address of the medium defect list 100 is obtained, and the offset value is subtracted from the physical address to convert the physical address into a virtual logical address.
It comprises a medium defect address conversion unit 12 passed to the search unit 11 and a medium access unit 13 for reading / writing the medium 4 with the physical address obtained by the search unit 11.

FIG. 2 shows the contents of the medium defect list 100 stored in the medium defect list storage unit 3. The medium defect list 100 stores the physical addresses of the defective sectors, uses one area per medium defect, and is arranged in ascending order. Access to the media defect list 100 is as follows.
The medium defect list 100 is stored in the medium defect list storage unit 3.
This is realized by specifying the offset value of.

FIG. 3 shows the format of the medium 4. Addresses are assigned to all the sectors of the medium in ascending order from the beginning and used as physical addresses. For sectors that are not defective sectors, logical addresses are assigned in order from the beginning.

Usually, the conversion from a physical address to a logical address is performed by knowing the number of defective sectors up to the logical address.
The number can be obtained by adding the number of defective sectors to the logical address.

However, if there is no physical address corresponding to the designated logical address, the number of defective sectors cannot be simply obtained.

Therefore, when there is no defective sector, the fact that the logical address matches the physical address is used.
Assuming that the given logical address is a physical address, a search is performed for the physical address in the medium defect table 100. As a result, if there is no defective sector up to the target logical address, the provisionally determined physical address becomes a true physical address. If there is a defective sector, at least the value obtained by adding the number of defective sectors to the temporary physical address should be the true physical address. Then, a search is again performed for the defective sectors in the range in which the number of the defective sectors is added, and the search is repeated until the defective sectors cannot be detected, thereby obtaining the physical address. However, in this method, since the search has to be repeated, the processing takes time.

In the present method, the medium defect address converter 12
Thus, the virtual logical address converted from the physical address indicates the next logical address of the defective sector.
Therefore, it is possible to obtain the number of defective sectors up to the logical address in the form of an offset value of the medium defect table 100 by searching only once for a virtual logical address larger than the first logical address appearing on the medium defect table 100. It becomes possible. Therefore, the number of defective sectors up to the logical address can be obtained, and the conversion from the logical address to the physical address can be performed at high speed.

Next, the overall operation of the present embodiment will be described in detail with reference to the flowcharts of FIGS. First, the logical address obtained by the input unit 1 is input to the search unit 21. Medium defect list 100
Is registered with physical sectors of defective sectors, and are arranged in ascending order. At the end of the media defect list 100, a physical address indicating the end of the media defect list is registered.
It is registered with a unique physical address that is sufficiently larger than the physical addresses of other registered defective sectors. In this example,
It is registered with the physical address “999”.

The search unit 11 performs a binary search with a logical address on the medium defect list 100 of the medium defect list storage unit 3 so that the first area to be compared is the entire medium defect list 100 (FIG. 4 step). 21). Next, the search unit 11 checks whether the size of the area to be compared is not one. If it is 1, the process proceeds to step 28, and if it is not 1, the process proceeds to step 23 (step 22). Search unit 11
Calculates the half offset value of the area to be compared (step 23). The search unit 11 passes the offset value to the medium defect list conversion unit 12 in order to obtain a virtual logical address designated by a half offset value calculated in step 23. The medium defect list converter 12 converts the medium defect list 10 specified by the given offset value.
By obtaining a physical address of 0 and subtracting the offset value, a virtual logical address is obtained, and the value is passed to the search unit 11 (step 24). The search unit 11 compares the logical address from the input unit 1 with the virtual logical address obtained by the medium defect list conversion unit 22. If the logical address is equal to or larger than the virtual logical address, the process proceeds to step 26,
If the logical address is smaller than the virtual logical address, the process proceeds to step 27 (step 25). When the logical address is equal to or larger than the virtual logical address, the search unit 11 newly sets a range larger than the current offset value in the area compared this time.
The region to be compared is set, and the process returns to step 22 (step 26). If the logical address is smaller than the virtual logical address, the search unit 11 newly sets a range that is equal to or less than the current offset value of the currently compared area as an area to be compared, and returns to step 22 (step 27). The search unit 11 repeats Steps 22 to 27 until the condition of Step 22 is satisfied. When the condition of Step 22 is satisfied, the search unit 11 exits this loop and proceeds to Step 28. The search unit 11 satisfies the condition of step 22 and calculates the offset value at the time of exiting the loop,
It is added to the logical address obtained by the input unit 1 to obtain a physical address (step 28). Finally, the medium access unit 1
3 accesses the medium 4 according to the physical address obtained by the search unit 11.

Next, a specific example will be described with reference to FIG. 1, FIG. 2, FIG. 3, and FIG.

The format of the medium 4 shown in FIG. 3 reflects the physical address of the defective sector in the medium defect list 100. No logical address is assigned to the physical sector at the defective sector position. Next, a normal physical address is assigned. For example, the logical address “3” is normally assigned next to the physical address of the logical address “2”, but the physical address of the next sector is “4” and is registered in the medium defect list 100. , Not assigned. Further, since the next physical address "5" is also registered, it is not allocated, and the physical sector "6" is finally allocated to the logical sector "3".

If the logical address “3” is actually specified by the host in the input unit 1 of FIG. 1, the input unit 1 passes the logical address “3” to the search unit 11. The search unit 11
In step 21 in FIG. 4, all areas of the medium defect list 100 in FIG. 2 in the medium defect list storage unit 3 are set as areas to be compared first. In step 22, it is determined whether the size of the area to be compared is one. In this case, since there are six areas to be compared, the process proceeds to the next step 23.

In step 23, an offset value of a half of the area to be compared is calculated to perform a binary search. In this case, since the size of the area to be compared is “6”, the offset value is “3”, which is half of that. In step 24, the offset value calculated above is passed to the medium defect list conversion unit 12. The medium defect list conversion unit 12
The physical address “8” of the medium defect list 100 determined by the given offset value “3” is obtained. After that, the offset value “3” is subtracted from the physical address “8” to obtain the virtual logical address “5”. Search unit 11
Compares the virtual logical address "5" obtained by the medium defect list conversion unit 12 with the logical address "3" in step 24. In this case, since the logical address is smaller than the virtual logical address, the process proceeds to step 27.
In step 27, an area smaller than the current offset value “3” is set as an area to be newly compared. In this case, the offset values “0” to “3” are targeted. After the area is reset, the process returns to step S22. In step 22, since the size of the reset area is "4", step 2
Proceed to 3. In step 23, the offset value "2" of the half of the area is obtained, and in step 24, the virtual logical address "3" is similarly obtained, and in step 25, the comparison with the logical address "3" is performed. In this case, since the logical address “3” is equal to or greater than the virtual logical address “3”, the process proceeds to step 26. In step 26, the area is set again to an area larger than the current offset value “3”. In this case, only the offset value “3” is targeted. Again, step 2
In step 2, the size of the area is determined. In this case, since the size of the area is 1, the process proceeds to step 28. In step 28, the logical address “3” is added to the offset value “3”.
Are added to obtain the physical address “6”. The search unit 11 passes the obtained physical address “6” to the medium access unit 23, and the medium access unit 13 accesses the sector of the medium 4 at the physical address “6”.

Next, another embodiment of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, FIG. 2, FIG. 3, and FIG. 5, first, the logical address obtained by the input unit 1 is passed to the search unit 11. The search unit 11 sets an offset value for sequentially searching by the above-described logical address in the medium defect list 100 of the medium defect list storage unit 3 at the beginning of the medium defect list 100 (Step 31 in FIG. 5). The search unit 11 determines that the offset value is the medium defect list 10
It is determined whether the end of 0 is indicated. As a result of the judgment, if it is the last, the process proceeds to step 36;
The process proceeds to Step 33 (Step 32). The search unit 11 passes the offset value to the medium defect list conversion unit 12, and the medium defect list conversion unit 12 obtains the physical address of the medium defect list 100 specified by the offset value.
The offset is subtracted from the obtained physical address to calculate a virtual logical address, which is returned to the search unit 11 (step 33). The search unit 11 compares the logical address from the input unit 1 with the virtual logical address obtained by the medium defect list conversion unit 22. If the logical address is equal to or greater than the virtual logical address, the process proceeds to step 35, If the address is smaller than the virtual logical address, the process proceeds to Step 36 (Step 34). The search unit 11 sets the offset value to 1
Increment and return to step 32 (step 3
5). The search unit 11 determines whether the condition of step 32 is satisfied or not.
When the condition of step 34 is no longer satisfied, the process exits the loop, and the offset value at that time is added to the logical address obtained by the input unit 1 to obtain a physical address (step 36). Lastly, the medium access unit 13 includes the search unit 1
According to the physical address obtained in step 1, access to the medium 4 is performed.

Next, referring to FIG. 1, FIG. 2, FIG. 3, and FIG.
A specific example will be described.

In the medium defect list 100 of FIG. 2, the physical addresses of the defective sectors are registered, and are arranged in ascending order. The last of the medium defect list 100 is the medium defect list 1
A physical address indicating the end of 00 is registered, and is registered with a unique physical address sufficiently larger than the physical addresses of other registered defective sectors. In this example, it is registered with the physical address “999”.

The format of the medium 4 in FIG. 3 reflects the physical address of the defective sector in the medium defect list 100, and no logical address is assigned to the defective sector. For example, the logical address “3” is normally assigned next to the logical address “2”, but is not assigned because the physical address of the next sector is “4” and is registered in the medium defect list 100. Also, since the next physical address “5” is also registered, it is not assigned,
Finally, the physical sector “6” is assigned to the logical sector “3”.

If the logical address “3” is actually specified by the host in the input unit 1 of FIG. 1, the input unit 1 passes the logical address “3” to the search unit 11. The search unit 11
In step 31 in FIG. 5, the head of the medium defect list 100 in FIG. 2 in the medium defect list storage unit 3 is set to an offset value. In this case, “0” is set. In step 32, it is determined whether the physical address of the medium defect list 100 specified by the offset value is “999” indicating the end of the medium defect list. In this case, the offset value is “0” and the physical address is “1”. Step 33
Then, the offset value is passed to the medium defect list conversion unit 22. The medium defect list conversion unit 12 obtains the physical address “1” of the medium defect list 100 specified by the given offset value “0”. After that, this physical address “1”
Is subtracted from the offset value “0” to obtain a virtual logical address “1”. In step 34, the search unit 11 compares the virtual logical address “1” obtained by the medium defect list conversion unit 12 with the logical address “3”.
In this case, since the logical address is equal to or greater than the virtual logical address, the process proceeds to step 35, where 1 is added to the current offset value “0” in step 35, and the process returns to step 32. In step 32, since the end of the medium defect list 100 is not yet reached, the process proceeds to step 33. In step 33, a virtual logical address "3" is obtained as described above. In step 34, comparison with the logical address "3" is performed. In this case, since the logical address "3" is equal to or greater than the virtual logical address "3", the process proceeds to step 35, where the offset value is incremented by one. Steps 32 to 35 are repeated several times while incrementing the offset value by 1. When the offset value becomes "3", in step 33, the logical address "3" is smaller than the virtual logical address "5". Then, the processing exits from the loop and proceeds to step 36. In step 36, the logical address "3" is added to the offset value "3" to obtain the physical address "6". The search unit 11 passes the obtained physical address “6” to the medium access unit 13, and the medium access unit 13 accesses the sector of the medium 4 at the physical address “6”.

[0028]

As described above, according to the present invention, the number of searches for the medium defect list when converting from a logical address to a physical address can be reduced to one and the speed can be increased.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a diagram showing the contents of a medium defect list 100.

FIG. 3 is a format diagram of a medium 4.

FIG. 4 is a flowchart illustrating a first method of address translation.

FIG. 5 is a flowchart illustrating a second method of address translation.

[Explanation of symbols]

 Reference Signs List 1 input unit 11 search unit 12 medium defect list conversion unit 13 medium access unit 3 medium defect list storage unit 4 medium 21 to 28, 31 to 36 steps

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G06F 12/16 310 G06F 3/06 306 G11B 20/10 G11B 20/12 G11B 27/10

Claims (9)

(57) [Claims] 1. A position of a medium defective sector on a magnetic disk is registered for each defective sector with a physical address allocated to all sectors including the defective sector in ascending order.
A method of converting a specified logical address into a physical address using a medium defect list referenced by an offset value in which addresses are assigned in ascending order from a specified address value. Subtracting the offset value from the physical address on the media defect list, and changing the offset value until the obtained virtual logical address becomes larger than the specified logical address, An address conversion method for a magnetic disk device, wherein a physical address is obtained by adding the logical address to a final value. 2. A step of setting an area for comparing the specified logical address and the virtual logical address in the entire medium defect list; a step of determining whether the size of the area is 1; If the size is not 1, calculating an offset value that is half of the set area; and subtracting the offset value from a physical address on the medium defect list corresponding to the offset value, thereby obtaining the virtual logical address. And comparing the specified logical address with the virtual logical address. If the former is greater than or equal to the latter,
Setting a region larger than the current offset as a new region, and if the latter is larger than the former, setting a region equal to or smaller than the current offset value of the currently set region as a new region, and returning to the second step; The method according to claim 1, further comprising the step of adding a current offset value to the logical address if the size of the area is 1, to obtain a physical address. Setting the offset value at the beginning of the medium defect list; determining whether the offset value is at the end of the medium defect list; and setting the offset value at the end of the medium defect list. For example, a step of obtaining the virtual logical address by subtracting the offset value from a physical address on the medium defect list corresponding to the offset value, and comparing the specified logical address with the virtual logical address; If the former is greater than or equal to the latter, add 1 to the offset value and return to the second step; and if the offset value is the last in the list, and if the virtual logical address is greater than the logical address, Adding an offset value to said logical address to obtain a physical address. The method of 1, wherein the. 4. Accessing a recording medium with a logical address,
In the magnetic disk device which performs the medium defect processing, the position of the medium defective sector on the magnetic disk is registered for each defective sector with a physical address assigned to all sectors including the defective sector in ascending order, and the ascending order from 0 A medium defect list storage unit that stores a medium defect list to be referred to by an offset value assigned to an address, and an offset value from a physical address on the medium defect list corresponding to a specified offset value. A medium defect list converting means for subtracting the result and outputting the result as a virtual logical address; and obtaining the virtual logical address by designating an offset value to the medium defect list converting means; Change the offset value until the address appears, and set the final offset value to the previous value. Magnetic disk apparatus characterized by comprising: a search means for obtaining a physical address by adding to the logical address, of the medium, the medium access means for accessing the obtained physical address of a sector in the searching means. 5. The search means sets the offset value at the beginning of the medium defect list, calculates an offset of a half of the set area, obtains a virtual logical address by the medium defect list conversion means, The logical address is compared with the virtual logical address.If the former is equal to or greater than the latter, an area larger than the current offset value of the currently set area is set as a new area, and if the latter is larger than the former, the current area is set. The setting of an area smaller than the current offset value of the set area as a new area is repeated until the area size becomes 1, and the final offset value is added to the logical address to obtain a physical address. An apparatus according to claim 4. 6. The search means, after setting the offset value at the head of the medium defect list, obtains a virtual logical address by the medium defect list conversion means, and compares the logical address with the virtual logical address. If the former is greater than or equal to the latter, adding 1 to the offset value is repeated until the offset value is at the end of the medium defect list or the logical address is smaller than the virtual logical address, and the final offset value is set. 5. The apparatus according to claim 4, wherein said physical address is obtained by adding to said logical address. 7. The position of a medium defective sector on a magnetic disk is registered for each defective sector with a physical address assigned to all sectors including the defective sector in ascending order.
An address conversion program that converts a specified logical address to a physical address using a medium defect list in which addresses are assigned in ascending order from an address corresponding to the specified offset value; A medium defect list conversion process for subtracting the offset value from the physical address on the medium defect list and outputting the result as a virtual logical address; and specifying the offset value for the medium defect list conversion process, Searching means for obtaining an address, changing an offset value until a virtual logical address larger than a specified logical address appears, and adding a final value of the offset value to the logical address to obtain a physical address; For accessing the sector of the physical address obtained by the means A recording medium recording address conversion program for executing access processing to the computer. 8. The search process sets the offset value at the beginning of the medium defect list, calculates an offset of a half of the set area, and obtains a virtual logical address by the medium defect list conversion process. The logical address is compared with the virtual address, if the former is greater than or equal to the latter, the area of the currently set area, the area larger than the current offset value is set as a new area, if the latter is greater than the former, The setting of the area of the currently set area equal to or smaller than the current offset value to the new area is repeated until the area size becomes 1, the final offset value is added to the logical address, and the physical address is set. The recording medium according to claim 7, which is obtained. 9. The search process sets the offset value at the beginning of the medium defect list, obtains a virtual logical address by the medium defect list conversion process, compares the logical address with the virtual logical address, If the former is equal to or greater than the latter, adding 1 to the offset value is repeated until the offset value is at the end of the medium defect list or the logical address is smaller than the virtual logical address, and the final offset is added. The recording medium according to claim 7, wherein a physical address is obtained by adding a value to the logical address.