Abstract: A hard disk drive (HDD) according to an embodiment of the present invention uses three primary defect map (PDM) formats: a single-sector entry format; a multi-sector entry format; and a two-dimensional sector entry format. Methods of registering defective sectors in each such format are illustrated. Defects can be appropriately registered in a limited RAM capacity by selecting an appropriate format according to states of the defects on a magnetic disk.

Abstract: Embodiments of the invention provide a disk drive capable of preventing the deterioration of performance. In one embodiment, a disk drive includes a disk medium; a head capable of performing a read/write operation for accessing the disk medium to read information from and to write information to the disk medium; a head controller for controlling the position of the head so that the head describes a substantially spiral trajectory relative to the disk medium; and a controller capable of controlling the head controller, of performing a read/write operation for reading or writing information with reference to an identifier table associating sector identifiers identifying sectors on a specified track with logical block addresses, and of creating an identifier table for a track to be accessed next during the read/write operation.

Abstract: Embodiments in accordance with the present invention increase the reliability of a data storage device, and to reduce the circuit size. According to one embodiment of the present invention, a hard disk drive (HDD) executes not only error correction processing of data to be written to a magnetic disk, but also error correction processing of data stored in the DRAM. In the HDD according to this embodiment, one SRAM is shared by both kinds of error correction processing. As a result of executing the error correction processing of the data stored in the DRAM, the reliability of the HDD is improved. In addition, by using the same SRAM for the two kinds of error correction processing that differ from each other, it is possible to suppress the increase in circuit size.

Abstract: Embodiments in accordance with the present invention prevent abnormal action of the actuator of a disk drive. According to an embodiment of the invention, in the process of startup (power on reset (POR)), a hard disk drive (HDD) checks whether an arm electronics (AE) port table stored in an EEPROM agrees with the ports of an AE to which head device portions are actually connected before it starts the rotation of a magnetic disk to move the actuator onto a user data area. Thus, even if an HDA and a reused circuit board do not agree at the manufacture of the HDD, the abnormal action of the actuator can be prevented.

Abstract: A hard disk drive (HDD) according to an embodiment of the present invention uses three primary defect map (PDM) formats: a single-sector entry format; a multi-sector entry format; and a two-dimensional sector entry format. Methods of registering defective sectors in each such format are illustrated. Defects can be appropriately registered in a limited RAM capacity by selecting an appropriate format according to states of the defects on a magnetic disk.

Abstract: A HDD defragments itself while idle or in self-test when a defragmentation count exceeds a threshold. Also, the HDD combines G-list entries when a discontinuity count and a G-list entry density are both over a threshold.

Abstract: Embodiments of the invention provide a disk drive capable of preventing the deterioration of performance. In one embodiment, a disk drive includes a disk medium; a head capable of performing a read/write operation for accessing the disk medium to read information from and to write information to the disk medium; a head controller for controlling the position of the head so that the head describes a substantially spiral trajectory relative to the disk medium; and a controller capable of controlling the head controller, of performing a read/write operation for reading or writing information with reference to an identifier table associating sector identifiers identifying sectors on a specified track with logical block addresses, and of creating an identifier table for a track to be accessed next during the read/write operation.

Abstract: A HDD defragments itself while idle or in self-test when a defragmentation count exceeds a threshold. Also, the HDD combines G-list entries when a discontinuity count and a G-list entry density are both over a threshold.

Abstract: A method for registering a defect map within a hard disk drive is disclosed. A hard disk drive includes a recording disk, a head assembly, and a controller. Multiple sectors are formed on the recording disk, and the head assembly includes a head for reading/writing data from/to the recording disk. The controller, which controls the head assembly to read/write data from/to the recording disk, includes a defect sector positional information holding device and a sector identification device. The defect sector positional information holding device holds positional information of a defect sector disabled to read/write data therefrom/thereto the recording disk. The positional information includes the number of the defect sectors continued in a circumferential direction and in a radial direction of the recording disk.

Abstract: A method and system are disclosed to provide a defect map structure that can increase the throughput of a recording apparatus when the recording apparatus accesses a data recording medium. A defect register method according to the present invention includes the steps of detecting initial defective sectors, generating a primary defect map (PDM) where each absolute block address of initial defective sectors (D.ABA) is individually registered, discriminating a series of defective sectors consisting of a plurality of initial defective sectors with continuous D.ABA, which exist in the same track (tracks having the same cylinder identification number CYL and head identification number HED) from the individual resister PDM, and generating a PDM, where this series of defective sectors is registered in a batch, by registering a first absolute block address of the series of defective sectors (D.ABA.ST), and defective sector length (number of defective sectors D.LE) of the series of defective sectors.

Abstract: A method for registering a defect map within a hard disk drive is disclosed. A hard disk drive includes a recording disk, a head assembly, and a controller. Multiple sectors are formed on the recording disk, and the head assembly includes a head for reading/writing data from/to the recording disk. The controller, which controls the head assembly to read/write data from/to the recording disk, includes a defect sector positional information holding device and a sector identification device. The defect sector positional information holding device holds positional information of a defect sector disabled to read/write data therefrom/thereto the recording disk. The positional information includes the number of the defect sectors continued in a circumferential direction and in a radial direction of the recording disk.

Abstract: An Error Recover Procedure (ERP) is disclosed which, during execution of the ERP, while self-diagnosing the cause of error, dynamically changes the error recovery steps of the ERP. An appropriate ERP is selected and executed according to the detected error status.

Abstract: A method and apparatus for relocating the data in defect sectors having occurred in the storage medium of an information recording and reproducing apparatus is described. If a defect occurs in a sector of a user area, the data of it is relocated to a temporary storage area. The logical block addresses (LBA's) for a group of sectors including an alternate sector are sequentially reassigned by skipping the defective sector and including the alternate sector. Data in the group of sectors are read out from the rear part of the user area according to current LBAs, and written according to new LBAs. Since the addresses of new LBAs are smaller than those of current LBAs by the number of defect sectors, the original data is not destroyed in the writing.

Abstract: The present invention provides a disk drive, a load/unload unit, and a control method thereof which are capable of reliably unloading a head slider from a disk when power is turned off and enhancing reliability. A disk drive is equipped with a VCM spindle driver for rotating a disk, a magnetic head, an actuator mechanism for moving over the surface of the magnetic disk or to an evacuating position a head slider having the magnetic head, a ramp block, and a CPU/HDC (control means) for performing control of load and unload operations, speed control of the actuator mechanism, and control of an operation of reading or writing data from or to the disk. The CPU/HDC receives a specific command issued from the host immediately before power is turned off, and executes this command, then executes unload control, and notifies the host of command completion after the unload control has been completed.

Abstract: Even in the case of a full hang state where a command to reset software is entirely ineffective, memory dump can be stored even if there is no in-circuit emulator. An HDD itself monitors a command execution time, that is, the time between reception of a command from a host computer and completion of the process of the command. If the HDD judges that it has taken an abnormally long time, a memory dump will be automatically stored on a reserved area on a disk. The memory dump can be read out from the disk at any time so that an analysis can be made.

Abstract: To decrease the number of read errors of a storage device due to bus noise when data is transferred between a host apparatus and the storage device. When a read error due to bus noise is detected, transfer of data to a host apparatus is temporarily stopped when executing rereading to eliminate bus noise which is a cause of the read error. In a preferred embodiment bus noise errors are distinguished by looking at the frequency of errors and the retry count for the previous error. The error is detected as a bus noise error if the frequency is above a threshold and the retry count is below a threshold. Data transfer can be restarted when a buffer becomes full or when the reading of the data is successfully completed.

Abstract: An error recovery procedure (ERP) in a storage device such as a rotating magnetic hard disk drive is executed to the last step regardless of the established time-out period for an instruction, thereby more reliably recovering from errors. In accordance with one embodiment of the invention, when a disk drive receives a reset instruction from a host during the execution of an ERP, it executes the ERP until the error is recovered, or to the last step without interrupting the ERP. Further, in accordance with another embodiment of the invention, when a disk drive receives a reset instruction during the execution of an ERP, it stops execution of the ERP and holds the number K of the step which was completed immediately before stopping, and when receiving a retry instruction after that, sequentially executes the ERP from the K+1-th error recovery step.

Abstract: A disk drive has an error recovery procedure with a plurality of ERP steps. An unused capacity of an alternate area on a disk for reassigning data is determined. While executing the error recovery procedure, an execution condition for reassigning data is changed based unused capacity of the alternate area. Data is reassigned to the alternate area in response to the execution condition. This prevents the early loss of the alternate area.

Abstract: A magnetic recording medium which comprises a first magnetic layer on a base and a second magnetic layer thereon, the first magnetic layer containing magnetic particles having an average particle length (long axis diameter) of 0.4 to 0.7 .mu., the second magnetic layer containing magnetic particles having an average particle length (long axis diameter) of 0.25 to 0.35 .mu., the coercive force of which being 370 to 460 oersteds, and the ratio of coercive force of the upper or second layer to that of the lower or first magnetic layer being 1.05/l to 1.5/l. The magnetic recording medium has excellent sensitivity and frequency characteristics at entire frequency bands with less noise.

Abstract: Cobalt-containing iron oxide magnetic particles having a high coercive force and a small surface electrical resistance which are useful as a recording element for a magnetic recording medium, and a method for the preparation of the same comprising reducing acicular .gamma.-Fe.sub.2 O.sub.3 particles in a reducing gas or liquid until the iron oxide reaches an intermediate oxidation state between .gamma.-Fe.sub.2 O.sub.3 and Fe.sub.3 O.sub.4, dispersing the resulting iron oxide particles into an aqueous solution containing a cobalt salt and optionally a ferrous salt and an alkali of one equivalent or more to the metal salt(s), and heating the mixture at a temperature of higher than room temperature up to a boiling point of the mixture under an atmospheric condition such that the divalent iron is substantially not oxidized. The cobalt is thereby predominantly incorporated into the most outer layer of the acicular iron oxide particles.