Abstract:
A method for correcting a formatting error in a boot sector of a hard disk drive is disclosed. An error in a first formatting of a first hard disk drive is discovered, and a second formatting is extracted from a second hard disk drive storing second data. The erroneous first formatting is replaced with a modification of the second formatting, and first data is stored in the first hard disk drive with the modification of the second formatting. The first data is different from the second data.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     The present application is related to the following co-pending U.S. patent application filed on even date herewith, and incorporated herein by reference in its entirety: 
        Ser. No. 11/______ (AUS920050644US1), entitled “METHOD, SYSTEM AND COMPUTER PROGRAM PRODUCT FOR RECOVERY OF FORMATTING IN REPAIR OF BAD SECTORS IN FLASH MEMORY”.       
 
     
    
     BACKGROUND OF THE INVENTION  
       [0003]     1. Technical Field  
         [0004]     The present invention relates in general to data processing systems and in particular to hard disk drives associated with data processing systems. Still more particularly, the present invention relates to a system, method and computer program product for recovery of formatting in repair of bad sectors in hard disk drives associated with a data processing system.  
         [0005]     2. Description of the Related Art  
         [0006]     Due to advances in electronic and magnetic technology, the capacity of hard drives at any given price point is doubling annually. While the advances in storage capacity that have been witnessed over the past decade have enabled a revolution in the type and quantity of data that can be stored, the correlative reductions in size and increases in the speed of moving parts have created a daunting array of obstacles to reliability.  
         [0007]     The reliability of a hard drive is specified in terms of its mean time between failures (MTBF) and the unrecoverable error rate. Typical specifications for recent server-class drives are 1,000,000 hours MTBF and 1 unrecoverable error in 10 15  bits read. However, increases in hard disk density make it harder to maintain reliability due to lower flying heights, greater sensitivity to media defects and smaller scale. Difficulties with error frequency have prompted the creation of error-correction techniques.  
         [0008]     Some methods of error correction require manual intervention. Others, such as RAID (Redundant Array of Independent Disks) arrays (e.g., RAID-1 or RAID-5) are often used to further improve the reliability of storage systems by correcting a variety of errors through redundant storage. However, with high-capacity drives, a single level of redundancy is no longer sufficient to reduce the probability of data loss to a negligible level. Additionally and unfortunately, redundant storage of data or formatting increases both cost and storage capacity requirements.  
         [0009]     It is also possible for a disk drive to occasionally return erroneous data on a read command because a previous write command has not written to the correct location on the recording medium or because the drive failed to record on the medium at all. This type of failure may be due to an intermittent hardware failure or a latent design defect. For example, the drive might write the data to the wrong LBA (Logical Block Address) due to a firmware bug, or it may write off track, or it may fail to write at all because a drop of lubricant (commonly referred to as ‘lube’) lifts the head off of the disk surface. It may also fail to write due to any power interruption during a write or format operation.  
         [0010]     In data processing systems, failures to write carry the risk that formatting for data stored in a hard disk drive can become corrupted or damaged. As with the error correction methods for other problems in hard disks, prior art methods for recovering from corruption of formatting data involve the constant maintenance of redundant copies of the data or require that the user corrects the corruption of the formatting through replacement or manual repair.  
         [0011]     The state of prior art methods results in several drawbacks. First, maintaining redundant copies of formatting data is not desirable, due to the associated increase in storage requirements. This concern about storage requirements becomes particularly important in embedded systems or other systems in which storage resources are limited. Similarly, prior art methods that require the user to correct the corruption of formatting data through replacement or manual repair involve time costs to the user or information technology personnel. The reduction of such costs is desired.  
       SUMMARY OF THE INVENTION  
       [0012]     A method for correcting a formatting error in a boot sector of a hard disk drive is disclosed. An error in a first formatting of a first hard disk drive is discovered, and a second formatting is extracted from a second hard disk drive storing second data. The erroneous first formatting is replaced with a modification of the second formatting, and first data is stored in the first hard disk drive with the modification of the second formatting. The first data is different from the second data.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed descriptions of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:  
         [0014]      FIG. 1A  depicts a block diagram of a data processing system in which a preferred embodiment of the method, system and computer program product for recovery of formatting data for repair of bad sectors in a hard disk drive attached to a data processing system is implemented;  
         [0015]      FIG. 1B  depicts a hard disk drive attached to a data processing system in accordance with a preferred embodiment of the present invention;  
         [0016]      FIG. 1C  depicts selected sectors of hard disk drives attached to a data processing system in accordance with a preferred embodiment of the present invention;  
         [0017]      FIG. 2  illustrates a high-level logical flowchart of a method for reading and writing data, which includes performing recovery of formatting in repair of bad sectors in hard disk drive attached to a data processing system in accordance with a preferred embodiment of the present invention; and  
         [0018]      FIG. 3  depicts a high-level logical flowchart of a method for performing recovery of formatting in repair of bad sectors in a hard disk drive attached to a data processing system in accordance with a preferred embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]     The present invention takes advantage of a dual media image design, in which similar copies of formatting data, also called critical data, exist in different sectors in a hard disk drive or within multiple hard disk drives. If and when an interruption to an operation touching formatting data causes corruption of a sector of formatting data, the present invention detects the corruption and utilizes a similarly formatted sector as a template to reconstruct the corrupted formatting. The reconstructed formatting is then used to repair the corrupted sector, allowing the system to return to full capability and function without alerting the user to the corruption. The present invention provides a solution to data corruption without requiring specific redundant copies of formatting data or requiring user intervention.  
         [0020]     With reference now to figures and in particular with reference to  FIG. 1A , there is depicted a data processing system  100  that may be utilized to implement the method, system and computer program product of the present invention. For discussion purposes, the data processing system is described herein as having features common to a server computer. However, as used herein, the term “data processing system,” is intended to include any type of computing device or machine that is capable of receiving, storing and running a software product, including not only computer systems, but also devices such as communication devices (e.g., routers, switches, pagers, telephones, electronic books, electronic magazines and newspapers, etc.), data storage devices, and personal and consumer electronics devices (e.g., handheld computers, Web-enabled televisions, home automation systems, multimedia viewing systems, etc.).  
         [0021]      FIG. 1A  and the following discussion are intended to provide a brief, general description of an exemplary data processing system adapted to implement the present invention. While parts of the invention will be described in the general context of instructions residing as firmware within ROM within a server computer, those skilled in the art will recognize that the invention also may be implemented in a combination of program modules running in an operating system. Generally, program modules include routines, programs, components and data structures, which perform particular tasks or implement particular abstract data types. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.  
         [0022]     Data processing system  100  includes one or more processing units  102   a - 102   d , at least two units of flash memory  110  and  112  coupled to a memory controller  105 , at least one unit of RAM  111  coupled to memory controller  105 , and a system interconnect fabric  106  that couples memory controller  105  to processing unit(s)  102   a - 102   d  and other components of data processing system  100 . Commands on system interconnect fabric  106  are communicated to various system components under the control of bus arbiter  108 .  
         [0023]     Data processing system  100  further includes additional non-volatile bulk storage media, such as a first hard disk drive  104   a  and a second hard disk drive  104   b . First hard disk drive  104   a  and second hard disk drive  104   b  are communicatively coupled to system interconnect fabric  106  by an input-output (I/O) interface  114 . Although hard disks are described above, it should be appreciated by those skilled in the art that other types of media which are readable by a computer, such as a removable magnetic disks, CD-ROM disks, magnetic cassettes, hard disk drive cards, digital video disks, Bernoulli cartridges, and other later-developed hardware, may also be used to provide non-volatile bulk data storage in the exemplary computer operating environment. Additional non-volatile storage is provided in ROM  107 , which contains firmware  109  for performing various essential system operations. The present invention is performed using instructions stored as firmware  109  within ROM  107  and is illustrated with respect to two hard disk drives  104   a - 104   b  coupled to I/O interface  114 , which contains a formatting modification storage unit  180 . The present invention is also applicable to first hard disk drive  110  and second hard disk drive  112  and a wide range of other media that employ dual media image design.  
         [0024]     Data processing system  100  may operate in a networked environment using logical connections to one or more remote computers, such as remote computer  116 . Remote computer  116  may be a server, a router, a peer device or other common network node, and typically includes many or all of the elements described relative to data processing system  100 . In a networked environment, program modules employed by data processing system  100 , or portions thereof, may be stored in a remote memory storage device, such as remote computer  116 . The logical connections depicted in  FIG. 1  include connections over a local area network (LAN)  118 , but, in alternative embodiments, may include a wide area network (WAN).  
         [0025]     When used in a LAN networking environment, data processing system  100  is connected to LAN  118  through an input/output interface, such as a network adapter  120 . It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used.  
         [0026]     Referring now to  FIG. 1B , two hard disk drives attached to a data processing system in accordance with a preferred embodiment of the present invention is illustrated.  FIG. 1B  is a top view of the interior of two hard disk drives  104   a - 104   b  with the covers removed. Each of hard disk drives  104   a - 104   b  includes a suspension  198   a - 198   b  to urge a slider  196   a - 196   b  toward a disk  188   a - 188   b . Suspensions  198   a - 198   b  also provide gimbaled attachment of sliders  196   a - 196   b , which allows sliders  196   a - 196   b  to pitch and roll as sliders  196   a - 196   b  ride on air bearings. The data detected from disks  188   a - 188   b  by transducers on sliders  196   a - 196   b  is processed into a data readback signal by signal amplification and processing circuitry in integrated circuit arm electronics (AE) modules  190   a - 190   b  located near arms  194   a - 194   b . Arms  194   a - 194   b  are pivotal about joints  192   a - 192   b  to move sliders  196   a - 196   b  to a desired radial position. Tracks  184   a - 184   b  are located at radial positions on disks  188   a - 188   b . Groups of sectors  186   a - 186   b  are angularly spaced around the disk in tracks  184   a - 184   b . Groups of sectors  186   a - 186   b  are described in more detail with reference to  FIG. 1C .  
         [0027]     Turning now to  FIG. 1C , a set of selected sectors of hard disk drives attached to a data processing system in accordance with a preferred embodiment of the present invention are depicted. First hard disk drive  104   a  contains a group of sectors  186   a , containing four sectors  152   a - 158   a . Boot sector  152   a  contains a header  160   a , a partition table offset  162   a , partition names  164   a  and a partition table size  166   a , which are collectively referred to as formatting data  160   a - 166   a , while sectors  154   a - 158   a  contain stored data, such as that data used by applications. Second hard disk drive  104   b  contains a groups of sectors  186   b , containing four sectors  152   b - 158   b . Boot sector  152   b  contains a header  160   b , a partition table offset  162   b , partition names  164   b  and a partition table size  166   b , which are collectively referred to as formatting data  160   b - 166   b , while sectors  154   b - 158   b  contain stored data, such as that data used by applications. Thus, sectors  154   a - 158   a  of first hard disk drive  104   a  (and usually do) contain first data different from the second data within sectors  154   b - 158   b  of second hard disk drive  104   b.    
         [0028]     Turning now to  FIG. 2 , a high-level logical flowchart of a method for reading and writing data, which includes performing recovery of formatting for repair of bad sectors in storage systems attached to a data processing system in accordance with a preferred embodiment of the present invention is illustrated.  
         [0029]     For illustrative purposes, the exemplary discussion of  FIG. 2  and  FIG. 3  contained herein will refer to a format operation being performed on first hard disk drive  104   a , with the use of second hard disk drive  104   b  to provide backup format data. One skilled in the art will quickly realize that either of first hard disk drive  104   a  and second hard disk drive  104   b  may provide backup to the other during format operations. The process starts at step  200 , and then proceeds to step  204 , which depicts I/O interface  114  beginning a critical operation to a boot sector  152   a  of storage within hard disk drive  104   a . The process next moves to step  206 . At step  206 , I/O interface  114  reads sector  152   a  of first hard disk drive  104   a . The process then proceeds to step  208 , which illustrates I/O interface  114  updating a local copy of the data contained in boot sector  152   a  of first hard disk drive  104   a  read in step  206 . The process next moves to step  210 .  
         [0030]     At step  210 , I/O interface  114  erases the boot sector  152   a  of hard disk drive  104   a  read in step  206 . The process then proceeds to step  212 , which depicts I/O interface  114  performing verification and recovery functions, which are detailed below with respect to  FIG. 3 , on the formatting data  160   a - 166   a  of boot sector  152   a  read in step  206 . The process next moves to step  214 . At step  214 , I/O interface  114  rewrites boot sector  152   a  of first hard disk drive  104   a  read in step  206 . The process then ends at step  216 .  
         [0031]     Referring now to  FIG. 3 , a high-level logical flowchart of a method for performing recovery of formatting for repair of bad sectors in hard disk drive systems attached to a data processing system in accordance with a preferred embodiment of the present invention is depicted. The process starts at step  300  and then moves to step  302 , which illustrates I/O interface  114  verifying header  160   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206 . The process then proceeds to step  304 . At step  304 , I/O interface  114  determines whether the verification of header  160   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206  succeeded. If the verification of header  160   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206  did not succeed, then the process moves to step  306 .  
         [0032]     Steps  306 - 316  represent a generalized recovery process, which is used in response to the determination of a failure of a verification at any of step  304  and steps  318 - 328  (which are explained below). At step  306 , I/O interface  114  asserts an internal flag bit indicating a verification failure. The process next proceeds to step  308 , which illustrates I/O interface  114  copying a binary image of a boot sector  152   b  of second hard disk drive  104   b , which is similar to boot sector  152   a  of first hard disk drive  104   a  read in step  206 , to a formatting modification storage unit  180  in I/O interface  114 . The process then moves to step  310 , which depicts I/O interface  114  reading formatting data  160   b - 166   b  from the binary image in formatting modification storage unit  180  of boot sector  152   b  of second hard disk drive  104   b . The process next proceeds to step  312 . At step  312 , I/O interface  114  modifies, to the extent necessary, the formatting data  160   b - 166   b  from the binary image in formatting modification storage unit  180  of boot sector  152   b  of second hard disk drive  104   b  for use as a replacement for the corrupted formatting data  160   a - 166   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206 .  
         [0033]     The necessary modifications will vary with particular embodiments of the present invention and on the basis of differences between the particular type of hard disk drive used and the particular data stored in sectors  154   a - 158   a  of hard disk drive  104   a  and in sectors  154   b - 158   b  of hard disk drive  104   b . In a preferred embodiment, some data from formatting data  160   b - 166   b  is capable of direct reuse. For instance, data extracted from header  160   b  is directly reusable in header  160   a . Likewise, partition table offset  162   b  is directly reusable as partition table offset  162   a  and partition table size  166   b  is directly reusable as partition table size  166   a.    
         [0034]     In a preferred embodiment, partition names  164   a  will be derived by changing the trailing digit of partition names  164   b  to correspond to a designator identifying the hard disk drive  104   a  in which they exist. A preferred embodiment contains hard disk drive  104   b , which is designated by convention as ‘hard disk  2 ’ with partition names boot 2 , kern 2 , dump 2  and user 2 . A preferred embodiment also contains hard disk drive  104   a , which is designated by convention as ‘hard disk  1 ’. When modifying partition names  164   b  for use as partition names  164   a , memory controller  105  will create partition names boot 1 , kern 1 , dump 1  and user 1 .  
         [0035]     In alternative embodiments, other formatting data  160   b - 166   b , such as partition names  164   a  will be derived from a scan of the sectors  154   a - 158   a  of hard disk drives  104   a . Following block  312 , the process then moves to step  314 , which illustrates I/O interface  114  updating the sector  152   a  of hard disk drive  104   a  read in step  206  with the formatting created in step  312  for use as a replacement for the corrupted formatting data  160   a - 166   a  formerly present in the sector  152   a  of hard disk drive  104   a  read in step  206 . The process then ends at step  316 .  
         [0036]     Returning to the verification process at step  304 , if the verification of header  160   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206  succeeded, then the process moves to step  318 , which depicts I/O interface  114  verifying partition offset table  162   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206 . The process next moves  320 . At step  320 , I/O interface  114  determines whether verification of partition offset table  162   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206  succeeded. If I/O interface  114  determines that verification of partition offset table  162   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206  did not succeed, then the process moves to step  306 , which is described above. If I/O interface  114  determines that verification of partition offset table  162   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206  succeeded, then the process proceeds to step  322 . At step  322 , I/O interface  114  verifies the validity of various partition names  164   a  in boot sector  152   a  of first hard disk drive  104   a  read in step  206 .  
         [0037]     The process then proceeds to step  324 , which depicts I/O interface  114  determining whether verification of the validity of partition names  164   a  in boot sector  152   a  of first hard disk drive  104   a  read in step  206  succeeded. If verification of the validity of partition names  164   a  in boot sector  152   a  of first hard disk drive  104   a  read in step  206  did not succeed, then the process moves to step  306 , which is described above. If verification of the validity of partition names  164   a  in boot sector  152   a  of first hard disk drive  104   a  read in step  206  succeeded, then the process moves to step  326 , which illustrates I/O interface  114  verifying partition table size  166   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206 . The process then moves to step  328 . At step  328 , I/O interface  114  determines whether verification of partition table size  166   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206  succeeded. If verification of partition table size  166   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206  did not succeed, then the process moves to step  306 , which is described above. If verification of partition table size  166   a  of boot sector  152   a  of first hard disk drive  104   a  read in step  206  succeeded, then the process ends at step  316 .  
         [0038]     As shown with respect to first hard disk drive  104   a  and second hard disk drive  104   b , the present invention takes advantage of a dual media image design, in which similar copies of formatting data, also called critical data, exist in different boot sectors  152   a  and  152   b  in a hard disk drive or within multiple units of flash memory. If and when an interruption to an operation touching formatting data  160   a - 166   a  causes corruption of a boot sector  152   a  of formatting data  160   a - 166   a , the present invention detects the corruption and utilizes a similarly formatted boot sector  152   b  as a template to reconstruct the corrupted formatting data  160   a - 166   a . The reconstructed formatting is then used to repair the corrupted boot sector  152   a , allowing the system to return to full capability and function without alerting the user to the corruption.  
         [0039]     While the invention has been particularly shown as described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. It is also important to note that although the present invention has been described in the context of a fully functional computer system, those skilled in the art will appreciate that the mechanisms of the present invention are capable of being distributed as a program product in a variety of forms, and that the present invention applies equally regardless of the particular type of signal bearing media utilized to actually carry out the distribution. Examples of signal bearing media include, without limitation, recordable type media such as floppy disks or CD ROMs and transmission type media such as analog or digital communication links.