Patent Publication Number: US-6990607-B2

Title: System and method for adaptive storage and caching of a defect table

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/235,608 filed Sep. 27, 2000 under 35 U.S.C. 119(e). 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to manage defects in mass storage devices, and more particularly to distributing the defect table on the recording medium of the mass storage device and caching the defect table. 
     BACKGROUND OF THE INVENTION 
     In conventional mass storage devices, a defect table of a fixed, predetermined size, length and/or capacity is stored on the recording medium of each storage device. The defect table indicates unreliable portions of the recording medium. During production of the mass storage device, the mass storage device is tested to determine which portions, if any, of the recording medium are not sufficiently reliable for writing and reading of data. The address of the each of the unreliable portions is stored on the recording medium in the defect table. 
     Furthermore, the size of the defect table on the recording medium in conventional mass storage device is predetermined, and fixed, regardless of how many actual defects are found during testing. When the number of defects is greater than the capacity of the defect table on the recording medium, the mass storage device is discarded as unusable because unreliable portions of the mass storage device will not be identified in the defect table on the recording medium. 
     During operation of conventional mass storage devices, the defect table on the recording medium is read and the entire defect table on the recording medium is cached in a defect table in memory on the microcontroller or microprocessor of the mass storage device. The defect table on the recording medium has a predetermined size because of the limited size of the defect table in memory. The cached defect table is referred to by the microcontroller or microprocessor to determine which portions of the recording medium not to use. 
     For example, when the microcontroller or microprocessor receives a write command, the microcontroller or microprocessor will determine that the addresses indicated in the cached defect table that will not be used for writing data. When the defect table on the recording medium is cached, the entire defect table on the recording medium of the fixed size is cached. However, when the entire defect table is cached, the limitation of the size of the cached defect table limits the size of the defect table on the recording medium. This has problems, in that when the number of defects on the recording medium is less than the capacity of the cached defect table, memory is unnecessarily reserved for the cached defect table. In addition, the cached defect table is not optimized or adapted to the application of the mass storage device or the quantity of defects on the recording medium. 
     Where the mass storage device is a disc drive, during operation of disc drive, for every disc access, the target address is expressed as logical block address (LBA). The LBA is converted to a physical address expressed as a physical cylinder/head/sector (PCHS) address based on the physical layout of the drive and the information in the defect table. 
     One conventional scheme of managing defect tables is the fixed-spares-per-track defect scheme (FSPT). In FSPT, each track is allocated a fixed amount of spares throughout the whole disc drive. Defective sectors are slipped using the spare sectors assigned to each track. Unused spares can be used to replace grown defects that may occur during the drive&#39;s lifetime. When a track has more defective sectors than the reserved spare sectors, some of the sectors are reassigned to another track using linear replacement method to achieve the same logical sectors per track. In LBA to physical block address (PBA) translation using FSPT, the translation is based on a logical zone table that describes the logical layout of the drive. 
       FIG. 1  is a block diagram of a table  100  of a physical zone layout according to the conventional FSPT scheme of managing defects.  FIG. 2  is a block diagram of a table  200  of a logical zone layout according to the conventional FSPT scheme of managing defects. 
     The physical zone layout table  100  differs from the logical zone layout  200  in that one spare sector is reserved for every track. The conversion process from LBA to PCHS is accomplished by using the logical zone table  200  only as all logical zones are guaranteed a fixed number of sectors per zone. 
       FIG. 3  is a block diagram of a table  300  of track defects according to the conventional FSPT scheme of managing defects. During operation the entire defect table  300  is cached. The portions of the defect table  300  that correspond to, or are associated with, infrequently used or least recently used portions of the recording medium of mass storage device are cached. This is problematic in that infrequently used portions of the defect table  300  are cached. Therefore the cached defect table occupies more memory space than is typically useful. 
     The mass storage device is unusable when the defect table is larger than the defect buffer. During operation of the mass storage device, the cached version of the defect table (i.e. the defect buffer) will be updated when reliability problems are encountered with portions of the recording medium that are not identified by the defect table  300 . The addresses of the grown defects of the recording medium will be added to the cached defect table. Later, the defect table  300  that stored on the recording medium will be updated with the cached defect table. However, if the quantity of defects stored in the defect table  300  on the recording medium is equal to the maximum capacity of the quantity of defects that can be cached, the mass storage device is rendered unusable. 
     Furthermore, seek times can be lengthy when a singular defect table is physically distant from some of the data on the recording medium. The singular defect table on the recording medium is stored in a reserved portion of the recording medium. During operation of the mass storage device, the seek time between accesses to the defect table and the regions of the recording medium that store data can be relatively lengthy because of the relatively large physical distance between the defect table in the reserved area and the data regions. 
     What is needed is a system, method and apparatus that enables a defect table on the storage medium that is adaptable and dynamic in size, capacity and length to accommodate the actual number of defects on the recording medium. What is also needed is a system, method and apparatus that enables a cached defect table that is adaptable and dynamic in size, capacity and/or length to the portions of the defect table that correspond to, or are associated with, frequently used or most recently used portions of the recording medium of mass storage device. What is also needed is a system, method and apparatus that provides a defect table on the recording medium of the storage device that has a larger capacity than the defect buffer. What is also needed is a system, method and apparatus that provides the defect table on the recording medium to be stored in a manner that reduces the seek time between the regions of data and the defect table. What is further needed is a system, method and apparatus that provides a defect table on the volatile memory device of the mass storage device that is adapted or optimized in reference to the application of the mass storage device and/or the quantity of defects on the recording medium. 
     SUMMARY OF THE INVENTION 
     The above-mentioned shortcomings, disadvantages and problems are addressed by the present invention, which will be understood by reading and studying the following specification. 
     The present invention provides systems and methods in which one or more segments of a defect table are copied to a volatile storage medium of a mass storage device from a recording medium of the mass storage device. The defect table in volatile memory is partitioned into a plurality of segments that are physically distributed throughout the recording medium. The defect table in volatile memory is also known as a defect buffer. The volatile storage medium is operably coupled to a microcontroller of the mass storage device. In one embodiment of the present invention, the defect table is stored in a manner that reduces the seek time between the regions of data and the defect table. In another embodiment, the defect table on the volatile memory medium is adapted and/or optimized in reference to the application of the mass storage device and/or the quantity of defects on the recording medium. 
     In one embodiment of the present invention, a defect table on a recording medium of a mass storage device is partitioned into a number of smaller segments. A fixed number of segments of the defect table that are associated with the most recently accessed data regions will be cached into a defect buffer in a volatile memory device of the mass storage device, therefore reducing the amount of capacity required to store or cache the defect table information in the volatile memory device. In a related embodiment of the present invention, the quantity and/or capacity of defect table segments on the recording medium and/or the quantity and/or capacity of defect table segments in the defect buffer is adapted to the quantity of defects found on the recording medium during a factory test process, or adapted to the application, such as multimedia, of the mass storage device. In another related embodiment, the partitioning of the defect table on the recording medium is in reference to the distribution of the defects on the recording medium of the mass storage device. 
     In another embodiment of the present invention, the capacity of the defect buffer is determined without reference to the quantity of the defects on the recording medium. In the example where the defect buffer capacity is less than the quantity of defects on the recording medium, a scheme is implemented to manage the swapping of defect entries in and out of the defect buffer from the defect table on the recording medium. One example of such a scheme is a most-recently-used scheme. 
     In yet another embodiment of the present invention, a method for managing a defect table of a mass storage device includes obtaining the defect table from the recording medium of the mass storage device, and copying a portion of the defect table into a volatile storage medium. 
     Still another embodiment of the present invention is a method for managing a defect table that is partitioned into a quantity of one or more segments. The capacity of the partitioned defect table is determined to be bigger than the capacity of the defect buffer. Subsequently, one or more segments of the defect table that are within the capacity of the defect buffer are copied into the defect buffer in the volatile storage medium. 
     In still yet another embodiment of the present invention, a method includes obtaining the application, such as multimedia, of the mass storage device, and adapting the capacity of the defect buffer to the application. 
     In still yet a further embodiment of the present invention, a method includes obtaining the quantity of defects on the recording medium, such as multimedia, of the mass storage device, and adapting the capacity of the defect buffer to the quantity of defects on the recording medium. 
     The present invention describes systems, methods, and computer-readable media of varying scope. In addition to the embodiments and advantages of the present invention described in this summary, further embodiments and advantages of the invention will become apparent by reference to the drawings and by reading the detailed description that follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a table of a physical zone layout according to a conventional fixed-spares-per-track scheme of managing defects. 
         FIG. 2  is a block diagram of a table of a logical zone layout according to a conventional fixed-spares-per-track scheme of managing defects. 
         FIG. 3  is a block diagram of a table of track defects according to a conventional fixed-spares-per-track scheme of managing defects. 
         FIG. 4  is a block diagram that provides a system level overview of the operation of embodiments of the present invention for managing defects. 
         FIG. 5  is a flowchart of a method for managing a defect table of a mass storage device, according to an embodiment of the invention. 
         FIG. 6  is a flowchart of a method of an embodiment of copying one or more defect table entries that are most likely to be referenced again to a volatile memory device of the mass storage device. 
         FIG. 7  is a flowchart of a method of an embodiment of copying a defect table to a volatile memory device of the mass storage device that enables the defect table on a recording medium of a storage device that has a larger capacity than a defect buffer. 
         FIG. 8  is a flowchart of a method of an embodiment of a method of further steps to  FIG. 5  where the volatile storage medium is partitioned into a quantity of one or more segments based on an application of the mass storage device. 
         FIG. 9  is a flowchart of a method of an embodiment of adapting the defect table in volatile memory in which the application is a multimedia application. 
         FIG. 10  is a flowchart of a method of further steps to  FIG. 5  where the volatile storage medium is partitioned into a quantity of one or more segments based on a quantity of defects of the mass storage device. 
         FIG. 11  is a flowchart of a method of an embodiment of the adapting in  FIG. 10 . 
         FIG. 12  is a block diagram of an apparatus to manage a defect table of a mass storage device, according to an embodiment of the invention. 
         FIG. 13  is a block diagram of an apparatus that includes an embodiment of the transferor in  FIG. 12 , of one or more MRU portions of a defect table into a defect buffer in a volatile storage medium. 
         FIG. 14  is a block diagram of an apparatus that includes an embodiment of the transferor in  FIG. 12  that supports a defect table on a recording medium of a storage device having a larger capacity than a defect buffer. 
         FIG. 15  is a block diagram of an apparatus that includes apparatus components that are additional to apparatus in  FIG. 12 , where the defect buffer in the volatile storage medium is partitioned into a quantity of one or more segments. 
         FIG. 16  is a block diagram of an apparatus of an embodiment of the adapter in  FIG. 15  in which the application is a multimedia application. 
         FIG. 17  is a block diagram of an apparatus that includes apparatus components that are additional to apparatus in  FIG. 12 , where the defect buffer in the volatile storage medium is partitioned into a quantity of one or more segments. 
         FIG. 18  is a block diagram of an apparatus of an embodiment of the adapter in  FIG. 17 . 
         FIG. 19  is an exploded view of one embodiment of a disc drive of the present invention. 
         FIG. 20  is a schematic view of a computer system. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
     The invention described in this application is useful for all types of disc drives, including hard-disc drives, optical drives (such as CDROMs), ZIP drives, floppy-disc drives, and any other type of drive. 
     The detailed description is divided into four sections. In the first section, a system level overview of the invention is presented. In the second section, methods for an embodiment of the invention are provided. In the third section, apparatus of the invention is described. Finally, in the fourth section, a conclusion of the detailed description is provided. 
     System Level Overview 
       FIG. 4  is a block diagram that provides a system level overview  400  of the operation of embodiments of the present invention. Embodiments of the invention operate in a multi-processing, multi-threaded operating environment on a computer, such as computer  2000  in  FIG. 20 . 
     System  400  includes a recording medium  410  on a mass storage device  420 . The recording medium  410  includes a defect table  430 . The mass storage device  420  also includes a microcontroller  440  operably coupled to the recording medium  410 . The mass storage device  420  also includes a volatile memory device  450  operably coupled to the microcontroller  440 . The volatile memory device  450  further includes a portion identified as a defect buffer  460  for the defect table  430 . The defect buffer  460  is used by the microcontroller  440  to determine if particular portions of the recording medium  410  are associated with a defect that would prohibit use of the particular portions. 
     In one embodiment of the present invention, the size of the defect buffer  460  and the defect table  430  are not dependent upon the size of each other. In varying embodiments, the size of the defect buffer  460  is greater than, less than, or equal to, the size of the defect table  430 . 
     In one embodiment of particular interest, the size of the defect buffer  460  is less than the size of the defect table  430 . In this embodiment, the defect buffer  460  contains a portion or subset of the items in the defect table  430 . This embodiment solves the problem in the prior art of limiting the size of the defect table  430  to no greater than the size of the defect buffer  460 . This embodiment also provides the advantage of enabling a larger defect table  430  than would otherwise be possible, which in turn, enables mass storage devices with a relatively large quantity of defects to be usable. This embodiment also provides the advantage of enabling a defect buffer  460  with a relatively small size in comparison to the defect table  430 . 
     In another embodiment of the present invention, the defect table  430  is divided or segmented into a plurality of defect tables, such as defect tables  471  and  472 . This embodiment also provides the advantage of enabling defect tables that are distributed throughout the recording medium, such as a defect that is distributed in close physical location to the data region that the defect table is associated with. 
     In one example, the mass storage device  420  is a disc drive, such as magnetic disc drive  1900  in  FIG. 19 . 
     Description of the Preferred Embodiment 
       FIG. 5  is a flowchart of a method  500  for managing a defect table  430  of a mass storage device  420 , according to an embodiment of the invention. Method  500  includes obtaining  510  the defect table  430  from the recording medium  410  of the mass storage device  420 . Subsequently, method  500  includes copying  520  a portion of the defect table  430  into a defect buffer  460  in a volatile storage medium  450 . In one embodiment, obtaining the defect table  430  is reading the defect table  430 . The volatile storage medium  450  is operably coupled to a microcontroller  440  and/or a microprocessor of the mass storage device  420 . In one embodiment, the mass storage device  420  is a disc drive, such as disc drive  1900  in  FIG. 19 . In another embodiment, the volatile storage medium  450  is a cache. In further embodiments, volatile storage medium is random access memory (RAM). 
     In method  500 , a portion of the defect table  430  is copied into the volatile storage medium  450 . As a result, method  500  solves the problem in the prior art of limiting the size of the defect table  430  to no greater than the size of the defect buffer  460 . This embodiment also provides the advantage of enabling a larger defect table  430  than would otherwise be possible, which in turn enables mass storage devices  420  with a relatively large quantity of defects to be usable. This embodiment also provides the advantage of enabling a defect buffer  460  with a relatively small size in comparison to the defect table  430 . 
     The volatile storage medium  450  is operably coupled to a microcontroller  440  and/or a microprocessor of the mass storage device  420 . In one embodiment, the mass storage device  420  is a disc drive, such as disc drive  1900  in  FIG. 19 . In another embodiment, the volatile storage medium  450  is a cache. 
       FIG. 6  is a flowchart of a method  600  of an embodiment of the copying  520  in  FIG. 5  in which one or more defect table segments that are most likely to be referenced again are copied to a volatile memory device of the mass storage device. Method  600  includes determining  610  at least one of a plurality of portions of the defect table  430  that are associated with the most recently used (MRU) plurality of data regions of recording medium  410  of the mass storage device  420 . Method  600  also includes copying  620  at least one of the plurality of the MRU portions into the volatile storage medium  450 . 
     Method  600  improves the usefulness of the defect buffer  460  by copying the defect segments that are most likely to be referenced again. Thus a defect buffer  460  that stores defect segments that are most likely to be used can be reduced in capacity and size. As a result, method  600  solves the problem in the prior art of limiting the defect buffer  460  to at least the capacity of the defect table  430 . 
       FIG. 7  is a flowchart of a method  700  of an embodiment of the copying  520  in  FIG. 5  that enables a defect table on the recording medium of the storage device that has a larger capacity than the defect buffer. Method  700  includes determining  710  that the defect table is partitioned into a quantity of one or more segments. In a further embodiment, the segments are of equal size. In yet a further embodiment, the one or more segments are physically distributed throughout the recording medium. In addition, method  700  includes determining  720  that one or more segments will fit in a defect buffer, wherein the size and/or capacity of a portion and/or subset of the one or more segments is not greater than the predetermined and/or allocated size of the defect table in a volatile storage medium. Furthermore, method  700  also includes determining  730  that the defect table is bigger than the defect buffer, wherein the size of the defect table is greater than the predetermined and/or allocated size of a defect buffer in the volatile storage medium. 
     Thereafter, method  700  includes copying  740  the portion of the one or more segments of the defect table into the defect buffer in the volatile storage medium. Method  700  solves the need in the prior art for a system, method and/or apparatus that provides a defect table on the recording medium of the storage device that has a larger capacity than the defect buffer. The defect buffer is also known as a defect table buffer. 
       FIG. 8  is a flowchart of a method  800  of an embodiment of a method of further steps to method  500  where the volatile storage medium is partitioned into a quantity of one or more segments based on an application of the mass storage device. Method  800  includes obtaining  810  the application of the mass storage device. Method  800  also includes adapting  820  the quantity of the one or more segments of the volatile memory device to the application. For instance, to enable four simultaneous I/O streams for an audio/video application, the number of cache segments can be set at four. For this instance, the cache segment size is sixteen kilobytes, which at four bytes per defect entry, can store up to four thousand defect entries. 
     Method  800  satisfies the need in the prior art for a system, method and/or apparatus that provides a defect table on the volatile memory device of the mass storage device that is adapted or optimized in reference to the application of the mass storage device. 
       FIG. 9  is a flowchart of a method  900  of an embodiment of the adapting  820  in  FIG. 8  in which the application is a multimedia application. Method  900  includes obtaining  910  the quantity of simultaneous multimedia streams. Method  900  also includes setting  920  the quantity of the one or more segments in reference to the quantity of simultaneous multimedia streams. Method  900  satisfies the need in the prior art for a system, method and/or apparatus that provides a defect table on the volatile memory device of the mass storage device that is adapted or optimized in reference to the application of the mass storage device. 
       FIG. 10  is a flowchart of a method  1000  of further steps to method  500  where the volatile storage medium is partitioned into a quantity of one or more segments based on the quantity of defects of the mass storage device. Method  1000  includes obtaining  1010  the quantity of defects found during a manufacturing test process of the mass storage device. Method  1000  also includes adapting  1020  the quantity of the one or more segments to the quantity of defects. Method  1000  satisfies the need in the prior art for a system, method and/or apparatus that provides a defect table on the volatile memory device of the mass storage device that is adapted or optimized in reference to the quantity of defects on the recording medium. 
       FIG. 11  is a flowchart of a method  1100  of an embodiment of the adapting  1020  in  FIG. 10 . Method  1100  includes obtaining  1110  the quantity of available memory for storing the defect table in the volatile memory device. Method  1100  also includes determining  1120  the quantity of the one or more segments from the quantity of defects divided by the quantity of available memory. Method  1100  satisfies the need in the prior art for a system, method and/or apparatus that provides a defect table on the volatile memory device of the mass storage device that is adapted or optimized in reference to the quantity of defects on the recording medium. 
     Table 1 below shows an example of a defect table  430  that is partitioned into smaller segments,  471  and  472 , according to its coverage of data regions. Note that the size of the different defect zones are not necessarily equal. The size of the defect zones are dependent on the number of defect entries in the defect table segment. The number of defect entries per defect table segment is constant to facilitate caching. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Defect Table 
                   
               
               
                 Segment 
                 Data Region 
               
               
                   
               
             
            
               
                 0 
                 Cylinder 0–1050 
               
               
                 1 
                 Cylinder 1051–3011 
               
               
                 2 
                 Cylinder 3012–4320 
               
               
                 3 
                 Cylinder 4321–5399 
               
               
                 4 
                 Cylinder 5400–6429 
               
               
                 5 
                 Cylinder 6430–9599 
               
               
                 6 
                 Cylinder 9600–10698 
               
               
                 7 
                 Cylinder 10699–12799 
               
               
                   
               
            
           
         
       
     
     In Table 1, the most recently accessed data regions, as in method  600  in  FIG. 6 , are within cylinder 0–1050, cylinder 3021–4320, cylinder 5400–6429, and cylinder 9600–10698 of a disc drive, such as disc drive  1900  in  FIG. 19 . Only defect table segments 0, 2, 4 and 6 will be cached into the defect buffer. If any disc access occurs outside of these four regions, the least frequently used defect table segment will be flushed out of the defect buffer and replaced by the defect table segment that covers the newly accessed data region. 
     This approach is optimal for audio and video data storage applications, as in method  800  in  FIG. 8  and method  900  in  FIG. 9 , whereby the data access pattern is more predictable and localized. For example, there can be a maximum of four constant data streams being read from or written to the disc drive in a sequential manner. If all the four required defect table segments are cached into the defect buffer, this would minimize flushing of the cache. 
       FIG. 12  is a block diagram of an apparatus  1200  to manage a defect table  1230  of a mass storage device  1220 , according to an embodiment of the invention. Apparatus  1200  includes an obtainer  1205  of the defect table  1230  from the recording medium  1210  of the mass storage device  1220 . The obtainer  1205  obtains the defect table  1230  from the recording medium  1210 . The obtainer  1205  is operably coupled to the recording medium  1210 . In one embodiment, the obtainer  1205  of the defect table  1230  is a reader of the defect table  1230 . 
     In addition, apparatus  1200  includes a transferor  1225  of a portion of the defect table  1230  into a defect buffer  1260 . The transferor  1225  is operably coupled to the obtainer  1205 . The defect buffer  1260  is in a volatile storage medium  1250 . 
     The volatile storage medium  1250  is operably coupled to a microcontroller  1240  and/or a microprocessor of the mass storage device  1220 . In one embodiment, the mass storage device  1220  is a disc drive, such as disc drive  1900  in  FIG. 19 . In another embodiment, the volatile storage medium  1250  is a cache memory. In some embodiments, the cache memory is a cache selected from a group consisting of an associative cache, a first-in-first-out cache (FIFO), a multilevel cache, a single level cache, a chained cache, and a linked list cache. 
     In apparatus  1200 , a portion of the defect table  1230  is transferred into the defect buffer  1260 . Because only a portion of the defect table  1230  is transferred, apparatus  1200  solves the problem in the prior art of limiting the size of the defect table  1230  to no greater than the size of the defect buffer  1260 . Therefore, apparatus  1200  also provides the advantage of enabling a larger defect table  1230  than would otherwise be possible, which in turn, enables mass storage devices  1220  with a relatively large quantity of defects to be usable. This embodiment also provides the advantage of providing a defect buffer  1260  with a relatively small size in comparison to the defect table  1230 . 
       FIG. 13  is a block diagram of an apparatus  1300  that includes an embodiment of the transferor  1220  in  FIG. 12 , in which at least one of the plurality of the most-recently-used (MRU) portions of the defect table  1330  are transferred into the defect buffer  1360  in the volatile storage medium. Defect table  1330  is substantially similar to defect table  430  in  FIG. 4  and defect table  1230  in  FIG. 12 . Transferor  1305  includes a determiner  1315  of at least one of a plurality of portions of the defect table  1330  that are associated with the MRU plurality of data regions of recording medium  1310  of the mass storage device  1320 . The determiner  1315  is operably coupled to the defect table  1330  on the recording medium  1310 . 
     Transferor  1305  also includes a transferor  1325  of at least one of the plurality of the MRU portions of the defect table  1330  into the defect buffer  1360  in the volatile storage medium  1350 . The transferor  1325  is operably coupled to the determiner  1315 , the defect table  1330 , and the defect buffer  1360 . 
     Apparatus  1300  improves the usefulness of the defect buffer  1360  by transferring the defect entries that are most likely to be referenced again, from the defect table  1330  to the defect buffer  1360 . Thus, a defect buffer  1360  that stores defect entries that are most likely to be used, can be reduced in capacity and size. As a result, apparatus  1300  solves the problem in the prior art of enlarging the defect buffer  1360  to at least the capacity of the defect table  1330 , which enables a defect buffer  1360  of relatively smaller size, and a defect table  1330  of relatively larger size. 
       FIG. 14  is a block diagram of an apparatus  1400  that includes an embodiment of the transferor  1220  in  FIG. 12  that enables a defect table on a recording medium of a storage device having a larger capacity than a defect buffer. Transferor  1405  includes a partition determiner  1415  that determines that the defect table, such as defect table  1330  in  FIG. 13 , on the recording medium  1410  is partitioned into a quantity of one or more segments,  1471  and  1472 . In a further embodiment of apparatus  1400 , the segments are of equal size. In yet a further embodiment, the one or more segments,  1471  and  1472 , are physically distributed throughout the recording medium  1410  in locations that are close to the data that the segments are associated with. For example, in reference to Table 1, defect table segment 4 is stored on cylinder 5400 &amp; 6430 and defect table segment 6 is stored on cylinder 9600 &amp; 10699 respectively. 
     Partition determiner  1415  is operably coupled to the recording medium  1410 . Furthermore, transferor  1405  also includes a size determiner  1425  that determines that the defect table, such as defect table  1330  in  FIG. 13  is bigger than the defect buffer  1460 , wherein the size of the defect table  1330  is greater than the predetermined and/or allocated size of the defect buffer  1460  in the volatile storage medium  1450 . Size determiner  1425  is operably coupled to the recording medium  1410 . 
     Thereafter, transferor  1405  includes a segment transferor  1435  that transfers the portion of the one or more segments,  1471  and  1472 , of the defect table into the defect buffer  1460  in the volatile storage medium  1450 . Segment transferor  1435  is operably coupled to the recording medium  1410 , the partition determiner  1415 , and the size determiner  1425 . 
     Apparatus  1400  solves the need in the prior art for a system, method and/or apparatus that enables a defect table on the recording medium  1410  of the storage device  1420  that has a larger capacity than the defect buffer  1460 . 
       FIG. 15  is a block diagram of an apparatus  1500  that includes apparatus components that are additional to apparatus  1200  in  FIG. 12 , where the defect buffer  1560  in the volatile storage medium  1550  is partitioned into a quantity of one or more segments. Apparatus  1500  includes an obtainer  1515  of the application of the mass storage device  1500 . The obtainer  1515  obtains an indication of the type of application from a source, such as the reserved portion of the recording medium  1510 . 
     Apparatus  1500  also includes an adapter  1525  of the quantity of the one or more segments of the defect buffer  1560  in the volatile memory device  1550  to the application. For instance, to enable four simultaneous I/O streams for and audio/video application, the number of cache segments in the defect buffer  1560  is be set to four. For this case, the cache segment size is sixteen kilobytes, which at four bytes per defect entry, can store up to four thousand defect entries. The adapter  1525  is operably coupled to the obtainer  1515  and the defect buffer  1560 . 
     Apparatus  1500  satisfies the need in the prior art for a system, method and/or apparatus that provides a defect buffer  1560  on the volatile memory device  1550  of the mass storage device  1520  that is adapted or optimized in reference to the application of the mass storage device  1520 . 
       FIG. 16  is a block diagram of an apparatus  1600  of an embodiment of the adapter  1525  in  FIG. 15  in which the application is a multimedia application. Apparatus  1600  includes an obtainer  1610  of the quantity  1615  of simultaneous multimedia streams. Apparatus  1600  also includes a setter  1620  of the quantity of the one or more segments in reference to the quantity of simultaneous multimedia streams. Apparatus  1600  satisfies the need in the prior art for a system, method and/or apparatus that provides a defect table on the volatile memory device of the mass storage device that is adapted or optimized in reference to the application of the mass storage device. 
       FIG. 17  is a block diagram of an apparatus  1700  that includes apparatus components that are additional to apparatus  1200  in  FIG. 12 , where the defect buffer  1760  in the volatile storage medium  1750  is partitioned into a quantity of one or more segments. Apparatus  1700  includes an obtainer  1715  of the quantity of defects found during a manufacturing test process of the mass storage device  1720 . Apparatus  1700  also includes an adapter  1725  of the quantity of the one or more segments in the defect buffer  1760  to the quantity of defects. Apparatus  1700  satisfies the need in the prior art for a system, method and/or apparatus that provides a defect buffer  1760  on the volatile memory device  1750  of the mass storage device  1720  that is adapted or optimized in reference to the quantity of defects on the recording medium  1710 . 
       FIG. 18  is a block diagram of an apparatus  1800  of an embodiment of the adapter  1725  in  FIG. 17 . Apparatus  1800  includes an obtainer  1810  of the quantity  1815  of available memory for storing the defect table in the volatile memory device. Apparatus  1800  also includes a determiner  1820  of the quantity of the one or more segments  1825  from the quantity of defects  1830  divided by the quantity of available memory  1815 . Apparatus  1800  satisfies the need in the prior art for a system, method and/or apparatus that provides a defect table on the volatile memory device of the mass storage device that is adapted or optimized in reference to the quantity of defects  1830  on the recording medium. 
     The components of apparatus  1200 ,  1300 ,  1400 ,  1500 ,  1600 ,  1700 , and  1800  can be embodied as computer hardware circuitry or as a computer-readable program, or a combination of both. 
     More specifically, in the computer-readable program embodiment, the programs can be structured in an object-orientation using an object-oriented language such as Java, Smalltalk or C++, and the programs can be structured in a procedural-orientation using a procedural language such as C or assembly language. The software components communicate in any of a number of means that are well-known to those skilled in the art, such as Application Program Interfaces (A.P.I.) or interprocess communication techniques such as Remote Procedure Call (R.P.C.), Common Object Request Broker Architecture (CORBA), Component Object Model (COM), Distributed Component Object Model (DCOM), Distributed System Object Model (DSOM) and Remote Method Invocation (RMI). 
       FIG. 19  is an exploded view of one embodiment of a disc drive of the present invention, this embodiment showing one type of magnetic disc drive  1900  having a rotary actuator. The disc drive  1900  is one example of mass storage devices, such as compact disc (CDROM) devices, tape cartridge devices, digital versatile disc (DVD) or digital video disc (DVD) devices. Other embodiments include other configurations and data recording and/or reading technologies. The disc drive  1900  includes a housing or base  1912 , and a cover  1914 . The base  1912  and cover  1914  form a disc enclosure. Rotatably attached to the base  1912  on an actuator shaft  1918  is an actuator assembly  1920 . The actuator assembly  1920  includes a comb-like structure  1922  having a plurality of arms  1923 . Attached to the separate arms  1923  on the comb  1922 , are load beams or load springs  1924 . Load beams or load springs are also referred to as suspensions. Attached at the end of each load spring  1924  is a slider  1926 , which carries a magnetic transducer  1950 . In some embodiments, transducer  1950  includes an electromagnetic coil write head and a magneto-resistive read head. The slider  1926  with the transducer  1950  form what is often called the head. It should be noted that many sliders have one transducer  1950  and that is what is shown in the figures. It should also be noted that this invention is equally applicable to sliders having more than one transducer, such as what is referred to as an MR or magneto-resistive head in which one transducer  1950  is generally used for reading and another is generally used for writing. On the end of the actuator assembly  1920  opposite the load springs  1924  and the sliders  1926  is a voice coil  1928 . 
     Attached within the base  1912  is a first magnet  1931  and/or a second magnet  1930 . As shown in  FIG. 19 , the second magnet  1930  is associated with the cover  1914 . The first and second magnets  1930 ,  1931 , and the voice coil  1928  are the key components of a voice coil motor which applies a force to the actuator assembly  1920  to rotate it about the actuator shaft  1918 . Also mounted to the base  1912  is a spindle motor. The spindle motor includes a rotating portion called a spindle hub  1933 . In this particular disc drive, the spindle motor is within hub  1933 . In  FIG. 19 , a number of discs  1934  (one or more; four are shown) are attached to the spindle hub  1933  to form disc assembly. In other disc drives, a single disc or a different number of discs may be attached to the hub. The invention described herein is equally applicable to disc drives which have a plurality of discs as well as disc drives that have a single disc. The invention described herein is also equally applicable to disc drives with spindle motors, which are within the hub  1933  or under the hub. 
       FIG. 20  is a schematic view of a computer system  2000 . Advantageously, the invention is well-suited for use in a computer system  2000 . The computer system  2000  may also be called an electronic system or an information handling system and includes a central processing unit, a memory and a system bus. The information handling system includes a central processing unit  2004 , a random access memory  2032 , and a system bus  2030  for communicatively coupling the central processing unit  2004  and the random access memory  2032 . The computer system  2000  includes a disc drive device. The computer system  2000  may also include an input/output bus  2010  and several peripheral devices, such as  2012 ,  2014 ,  2016 ,  2018 ,  2020 , and  2022 , which may be attached to the input output bus  2010 . Peripheral devices may include hard disc drives, magneto-optical drives, floppy disc drives, monitors, keyboards and other such peripherals. Any type of disc drive may use the method for loading or unloading the slider onto the disc surface as described above. 
     CONCLUSION 
     In conclusion, systems and methods are disclosed through which the capacity of a defect buffer in a microcontroller of a mass storage is determined without regard for the quantity of defects on a recording medium. The capacity of the defect buffer is determined in varying examples, based on the amount of available space and/or the application of the storage device. In one embodiment, the capacity of the defect buffer is less than the quantity of defects on the recording medium, wherein entries in a defect table on the recording medium are swapped in and out of the defect buffer as needed, such as using a most-recently-used scheme. Systems and methods are also provided through which the defect table is divided or segmented into a plurality of defect tables that are physically distributed throughout the recording medium. 
     In one embodiment of the present invention, a method  500  for managing a defect table of a mass storage device includes obtaining  510  the defect table from the recording medium of the mass storage device, and copying  520  a portion of the defect table into a volatile storage medium. In one embodiment, the obtaining the defect table is reading the defect table. The volatile storage medium is operably coupled to a microcontroller and/or a microprocessor of the mass storage device. In one embodiment, the mass storage device is a disc drive, such as disc drive  1900  in  FIG. 19 . In another embodiment, the volatile storage medium is a cache. 
     One embodiment of the copying  520  includes determining  610  at least one of a plurality of portions of the defect table that are associated with the most recently used (MRU) plurality of data regions of the mass storage device, and copying  620  at least one of the portions of the defect table into a volatile storage medium. The volatile storage medium is operably coupled to the microcontroller of the mass storage device. 
     Another embodiment of the copying  510  includes determining  710  that the defect table is partitioned into a quantity of one or more segments. In a further embodiment, the segments are of equal size. In yet a further embodiment, the one or more segments are physically distributed throughout the recording medium. In addition, the copying  510  includes determining  720  that one or more segments will fit in a defect buffer, wherein the size of a portion and/or subset of the one or more segments is not greater than the predetermined and/or allocated size of the defect table in a volatile storage medium. The copying  510  also includes determining  730  that the defect table is larger than the defect buffer, wherein the size of the defect table is greater than the predetermined size of a defect table in the volatile storage medium. Thereafter, the copying  510  includes copying  740  the portion of the one or more segments of the defect table into the defect table in the volatile storage medium. 
     In an embodiment of method  500  where the volatile storage medium is partitioned into a quantity of one or more segments, method  500  also includes obtaining  810  the application of the mass storage device, and adapting  820  the quantity of the one or more segments to the application. In one embodiment of the adapting  820 , the application is a multimedia application and the adapting  820  includes obtaining  910  the quantity of simultaneous multimedia streams, and setting  920  the quantity of the one or more segments in reference to the quantity of simultaneous multimedia streams. 
     In an embodiment of method  500  where the volatile storage medium is partitioned into a quantity of one or more segments, method  500  also includes obtaining  1010  the quantity of defects found during a manufacturing test process of the mass storage device, and adapting  1020  the quantity of the one or more segments to the quantity of defects. In one embodiment of the adapting  1020 , the adapting includes obtaining  1110  the quantity of available memory for storing the defect table in the volatile memory device, and determining  1120  the quantity of defects divided by the quantity of the one or more segments from the quantity of available memory. 
     In one embodiment of the present invention an apparatus for managing a defect table  1230  stored on a recording medium  1210  of a mass storage device  1220  includes an obtainer  1205  of the defect table  1230  from the recording medium  1210  of the mass storage device  1220 , wherein the defect table  1230  is partitioned into a plurality of portions, and a transferor  1225  of one of the plurality of portions of the defect table into a volatile memory device  1250 , the transferor  1225  being operably coupled to the obtainer  1205 . 
     In one embodiment of the transferor  1225 , the transferor includes a determiner  1315  of at least one of a plurality of portions of the defect table that are associated with a plurality of most-recently-used data regions of the recording medium of the mass storage device, the determiner being operably coupled to the defect table on the recording medium, and a transferor  1305  of at least one of the plurality of the most-recently-used portions of the defect table into the volatile storage device  1350 , the transferor  1325  being operably coupled to the determiner  1315 , the defect table  1330 , and the defect buffer  1360 . 
     In another embodiment of the transferor  1225 , the transferor  1225  includes a partition determiner  1415 , that determines that the defect table on the recording medium  1410  is partitioned into a quantity of one or more segments,  1471  and  1472 , the partition determiner  1415  being operably coupled to the recording medium  1410 , a defect table size determiner  1425 , that determines that the defect table on the recording medium is bigger than the defect buffer  1460  in the volatile memory device  1450 , the size determiner  1425  being operably coupled to the recording medium  1410 , and a segment transferor  1435 , that transfers the portion of the one or more segments of the defect table on the recording medium  1410  into the defect buffer  1460  in the volatile storage device  1450 , the segment transferor  1435  being operably coupled to the recording medium  1410 , the partition determiner  1415 , and the size determiner  1425 . In a further embodiment, the one or more segments,  1471  and  1472 , include one or more segments that are physically distributed throughout the recording medium  1410 . 
     In yet a further embodiment of the present invention, a defect buffer  1560  in the volatile storage medium  1550  is partitioned into a quantity of one or more segments, and the apparatus includes an obtainer  1515  of the application of the mass storage device  1510 , that obtains an indication of the type of application from a source, and an adapter  1525  that adapts the quantity of the one or more segments of the defect buffer  1560  in the volatile memory device  1550  to the application, the adapter  1525  being operably coupled to the obtainer  1515  and the defect buffer  1560 . In a further embodiment, where the application is a multimedia application, the adapter  1525  includes an obtainer  1610  of the quantity  1615  of simultaneous multimedia streams, and a setter  1620  of the quantity of the one or more segments in reference to the quantity  1615  of simultaneous multimedia streams, the setter  1620  being operably coupled to the obtainer  1610  of the quantity of simultaneous multimedia streams. 
     In still a further embodiment of the present invention, wherein a defect buffer  1760  in the volatile storage medium  1750  is partitioned into a quantity of one or more segments, the apparatus includes an obtainer  1715  of a quantity of defects found during a manufacturing test process of the mass storage device  1720 , and an adapter of the quantity of the one or more segments in the defect buffer  1760  to the quantity of defects, the adapter being operably coupled to the obtainer  1715 . 
     It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.