Abstract: In general, in one aspect, the description includes a method of responding to storage access requests. The method includes defining at least one write area and at least one read-only area, receiving a write request specifying a first address that resides within the at least one read-only area, determining a second address in the write address area, and storing data associating the first address with the second address.

Abstract: A virtual mass storage device implements a data manager for storing information on multiple physical mass storage devices. The virtual mass storage device is organized into blocks of information which are allocated to different physical devices, thereby enabling the physical devices to operate in parallel and increase the overall transfer rate of the virtual device.

Abstract: A method for performing full optimization of most of the files on a volume in accordance with a composed optimization plan, is performed, including the separation of less frequently accessed files from those whose number or location of clusters is being more frequently modified by user applications. Optimization does not continue indefinitely—it reaches a final state even if a small percentage of its file data is still out of place under the optimization plan and therefore not in the planned part of a plan-defined, Placed Files Area. Each time a Push of out-of-place file data is attempted, or a Pull of file data into a correspondingly planned free space within the Placed Files Area is attempted, a copy of the current volume bitmap is made in order to determine what is the largest free space currently available in the Placed Files Area. Once determined, the size of the largest free space is compared to the size of the largest out-of-place range of corresponding clusters in the Placed Files Area.

Abstract: A system is configured to prioritize streaming disk I/O over non-streaming disk I/O by providing high priority queuing to streaming disk I/O and/or to throttle non-streaming disk I/O when the total disk I/O (streaming+non-streaming) exceeds a threshold amount for a given time quantum. When disk throttling is utilized, streaming disk I/O is processed in a first time quantum. Non-streaming disk I/O is processed, as much as possible, in the remainder of the first time quantum. Other non-streaming disk I/O remaining to be processed is deferred to a subsequent time quantum.

Abstract: A computer operating system method for use with removable computer memories such as optical disks, including write-once disks and write-many disks, for preserving and allowing access to prior generations of a data set, including any kind of data file. When the system is used with a write-many memory, such as a re-writeable CD, the system functions are limited so that generations of the data set older than the currently open generation cannot be revised, even though the physical media would allow revision if the system did not limit this function. To ensure that data written to a write-many disk cannot easily be revised with commonly available software, the data address table for accessing the data is written in a location that is not recognized by available software and is only recognized by software created in accordance with this invention: specifically, the data address table is written in the highest available sector while new versions of the data set are written in the lowest available sector.

Abstract: A system for responding to file system requests having file IDs comprising V, a volume identifier specifying the file system being accessed, and R, an integer, specifying the file within the file system being accessed. The system includes D disk elements in which files are stored, where D is greater than or equal to 1 and is an integer. The system includes a switching fabric connected to the D disk elements to route requests to a corresponding disk element. The system includes N network elements connected to the switching fabric. Each network element has a mapping function that for every value of V, specifies one or more elements from the set D that store the data specified by volume V, where N is greater than or equal to 1 and is an integer and N+D is greater than or equal to 3, which receives the requests and causes the switching fabric to route the requests by their file ID according to the mapping function. A method for responding to file system requests.

Abstract: A headless computer entity comprises a RAID array data storage device. The headless computer entity contains a management application, capable of configuring said RAID data storage device from a blank unformatted condition into a plurality of RAID volumes, and maintaining said RAID data storage device when in operation under error conditions, and reconfiguring said RAID data storage device under conditions of replacement of a physical data storage component of said RAID array.

Abstract: A disk cache controlling method and a disk array system which includes a plurality of disk devices and a disk cache. Data is divided and stored into the disk devices and a plurality of volumes are assigned to the disk devices. A disk array controller controls the disk devices. Assignment of new disk cache areas includes dividing each of the volumes into areas with an arbitrary fixed length, determining an access frequency for each of the divided areas of each of the volumes; and changing assignment of the disk cache areas to the divided areas according to an access frequency for each divided area. The disk cache areas are assigned to the divided areas according to a divided area having an access frequency which is the lowest.

Abstract: The present invention provides a memory system which contributes to improvement in efficiency of a data process accompanying a memory access. A memory system has a rewritable nonvolatile memory, a buffer memory, and a controller. The controller controls, in response to an access request from an external apparatus, first data transfer between the controller and the external apparatus, second data transfer between the controller and the nonvolatile memory, and third data transfer between the controller and the buffer memory, controls transfer from the controller to the buffer memory in the third data transfer and transfer from the buffer memory to the controller in a time sharing manner, and enables the first data transfer or the second data transfer to be performed in parallel with the transfer carried out in the time sharing manner.

Abstract: A system and method for backing up data from a plurality of client computer systems. A server computer executes a plurality of processes each configured to receives back-up data from a respective one of the client computers. Each of the processes stores the back-up data into a buffer within a shared memory area. The server computer associates an identification tag with each set of back-up data which identifies from which particular client computer the data was received. The server computer then stores the back-up data and the identification tags within a storage unit. Data from a particular client is de-multiplexed from the storage unit by scanning all of the identification tags in the storage unit and sending any data which is associated with a received identification tag to the particular client.

Abstract: A system for automatically migrating a portion of a collection of information located on source data carrier(s) into an assemblage of data carriers, having: a computer memory for pass-through of a first strip of the collection; the assemblage has at least a first storage medium to which at least a first sub-portion of the first strip is written from computer memory; and once the portion of the collection has been so migrated according to a predetermined structure, a remaining portion of the collection can be written to the source data carrier (to include the source data carrier in the assemblage), the remaining portion being ordered (crunched) in conformity with the predetermined structure.

Abstract: A new storage system architecture is described that satisfies the requirements of high availability and high performance. High performance is achieved by utilizing both parallel RAID data paths to disk and a split read and write cache. The read cache is associated with a host interface controller and the write cache is distributed over independent multi-ported write cache controllers operating within a battery protected power domain. Disk and write cache failures are survived through disk redundancy; controller redundancy provides system level survival for system faults. The system is therefore tolerant of both component and power failure, including combined component and power failure.

Abstract: A volume provider unit in a computer system detects a logical block address of a read or write I/O accessing a logical volume of a storage device from a host. According to the logical block address fetched, a storage domain of the logical volume is dynamically expanded. Moreover, the storage domain of the logical volume is reduced or expanded according to an instruction of a logical volume capacity reduction or expansion from a host commander part to a volume server.

Abstract: A process/method for controlling a digital data storage unit including a multiplicity of storage media slots for receiving media storage units, a plurality of media storage units loaded in some of the storage media slots, a plurality of data storage drives each having a unique drive address, a loader mechanism for selectively moving a media storage unit between a storage media slot and one of the plurality of data storage drives, and a storage unit controller connected to at least one host computer. One or more of the data storage drives are reserved as spare data storage drives wherein the spare data storage drives are masked from the host computer such the spare data storage drives are not directly accessible by the host computer. The storage unit controller receives and decodes host commands including a source address corresponding to a storage media slot location, and a destination address corresponding to a data storage drive specified by the host computer.

Abstract: An information recording/reproduction apparatus according to one aspect of this invention includes a first recording/reproduction unit configured to execute recording, reproduction, and deletion of information for a built-in first recording medium, a second recording/reproduction unit configured to execute recording and reproduction of information for a detachable second recording medium, a recording control unit configured to control to record a library information file, that contains a plurality of pieces of library information corresponding to a plurality of contents information recorded on the first and second recording media, on the first recording medium, and a deletion control unit configured to execute a process for deleting all pieces of library information contained in the library information file, and a process for deleting all pieces of contents information recorded on the first recording medium.

Abstract: A hard disk on which table information varying depending on the model of a hard disk drive (HDD) is directly written includes: a hard disk assembly (HDA) having a hard disk for storing table information varying depending on the model of the HDD in a predetermined region of a data zone; and a main board having a RAM for reading and storing table information stored in the hard disk, a ROM for storing common table information irrelevant to the model of the HDD and programs for controlling the hard disk assembly and reading and writing of data, and a controller for reading and writing data according to the table information and programs stored in the RAM and ROM. Therefore, by storing table information varying depending on the model of an HDD in a disk and not in a ROM, a main ROM installed in the main PCB can be constructed with the same structure regardless of the model of an HDD, thereby simplifying the manufacturing process of the HDD.

Abstract: An input/output scheduling unit forms input/output groups obtained by grouping inputs/outputs to/from a disk apparatus. The input/output scheduling unit defines a ratio of the time during which each input/output group uses the disk apparatus and defines quanta &tgr;1 to &tgr;3 during which each input/output group can continuously use the disk apparatus on the basis of the defined time ratios. When input/output requests are received from a plurality of input/output groups to the disk apparatus, the input/output scheduling unit performs the time-sharing for sequentially switching the allocating times &tgr;1 to &tgr;3 between the input/output groups which competed and using the disk apparatus. Further, an allocating time of the remaining quanta is distributed to the quanta on the shortage side by an allocating time control unit in accordance with a degree of jam of each input/output group.

Abstract: A method to import a logical volume and first storage attributes assigned to that logical volume into a second virtual tape system from first virtual tape system, where the first virtual tape system is capable of communicating with one or more first host computers, and where the second virtual tape system is capable of communicating with one or more second host computers. The method maintains a logical volume in a first direct access storage device file buffer disposed in the first virtual tape system, assigns one or more first storage attributes to that logical volume, assigns an identifier to the logical volume, and writes an export physical volume that includes the logical volume, the one or more assigned first storage attributes, and the logical volume identifier. The method defines in the second virtual tape system a plurality of second storage attributes.

Abstract: A system, apparatus, and method to recover a logical volume on a read-only physical volume, or data storage cartridge, within a dual copy data storage system, such as a virtual tape server (VTS) system. The recovery follows a disaster situation involving the primary physical volume and the requested logical volume. The system, apparatus, and method include modules and steps as required to recover a logical volume through recalling a selective dual copy of the logical volume stored on a secondary physical volume. The primary and secondary logical volumes are stored on distinct physical volumes in order to provide quality storage media management and reduce the likelihood of loss of data. The recovery and recall procedures are implemented in a manner that is substantially transparent and asynchronous to a host or client. Additionally, the recovery and recall require no additional input from the host in order to carry out the recovery of the logical volume.

Abstract: A DVD disc contains a lead-in area that contains sync sectors, control data including the number of recording surfaces, disc keys and other information, and contains a Data Area occupying the main part of the available disc surface or surfaces. In order to handle the content of the disc it is necessary to know the control data and disc keys. According to the invention, the data content of the Data Area is used to determine the necessary control data, without reading information from the a lead-in area.

Abstract: A system, method, and apparatus are provided for copying a virtual volume to multiple physical volumes within a virtual tape system. The virtual tape system may include a virtual tape server (VTS), a library manager, and a plurality of tape drive units into which cartridges may be individually mounted. The virtual tape system stores virtual volumes, each of which represents a physical volume, although one or more virtual volumes are actually stored on a real physical volume. The library manager contains a volume database with a plurality of constructs and associated storage management actions. The constructs are received from a host computer connected to the VTS, but the storage management actions may be entered directly into the library manager, independently of the host. The library manager reads the management action associated with one or more constructs of a virtual volume and, along with the VTS, determines whether multiple physical copies of the virtual volume are to be made.

Abstract: Provided are a method, system, and article of manufacture for pooling of storage. Volume attributes are assigned to a plurality of physical volumes. Pool attributes are assigned to a plurality of storage pools, wherein the pool attributes include policies for borrowing and returning the plurality of physical volumes to and from the plurality of storage pools. One of the plurality of physical volumes is allocated to one of the plurality of storage pools based on the volume attributes of the one of the plurality of physical volumes and the pool attributes of the one of the plurality of storage pools.

Abstract: A method to assign one or more new storage construct names to one or more logical volumes using an operator input station capable of communicating with a virtual tape system, where that virtual tape system includes a plurality of existing logical volumes and a database which includes a plurality of logical volume records. The method first defines one or more new storage construct names, associates one or more storage actions with each of those new storage construct names, and saves the new storage construct names and the associated storage actions in the database. The method then enters, using the operator input station, a range of logical volumes, selects one or more new storage construct names, associates those new storage construct name to the range of logical volumes. The method then determines if the range of logical volumes comprises existing or new logical volumes.

Abstract: A method to maintain information in a virtual tape system comprising a library inventory using a plurality of storage attributes. The method includes forming a dataset comprising information, and assigning one or more storage construct names to that dataset. The method provides the dataset and the one or more storage construct names to the virtual tape system. The method assigns a plurality of storage attributes to the logical volume using the one or more storage construct names. The method then selects storage management actions for the logical volume based upon those assigned storage attributes.

Abstract: In a disk drive, a read-ahead operation is prevented from being aborted due to an interrupt such as an error, to prevent the operation of a host device from stopping and to enhance reliability. The disk drive is connected to a host computer, the host device, via an interface, and performs read ahead after reading data in accordance with a data read command received from the host computer. When a read-ahead abort prevention function is provided at the host computer side, if the read ahead is interrupted by detecting an error at the disk drive side during the read ahead, the host device, after receiving an error report, causes the disk drive to resume the read ahead from the address at which the read ahead was interrupted. On the other hand, when the read-ahead abort prevention function is provided at the disk drive side, the disk drive, upon detecting an error, retries the read ahead from the address at which the error occurred.

Abstract: One embodiment of the disclosures made herein is a method for facilitating restoration of a system configuration of a data processing system. In accordance with such embodiment, a hidden recovery partition and an active system configuration partition are created on a first resident storage unit of a data processing system. An image of a baseline system configuration is stored in the hidden recovery partition. A modified system configuration is created and is stored in the active system configuration partition. The modified system configuration is modified with respect to the baseline system configuration. The data processing system is operated in accordance with the modified system configuration. The image of the baseline system configuration is accessed for restoring operation of the data processing system in accordance with the baseline system configuration.

Abstract: A method for improving disk drive performance by reducing the overhead associated with the command processing code requesting a seek. As multiple commands are queued up in a command queue, a next command is identified and immediately stored in a servo position queue, as soon as the next command location is determined. Therefore, as the drive electronics are prepared for read and write operations, the servo system initiates the actuator to move the read/write head to the next command location. By the time the read/write head arrives at the next command location, the drive electronics are ready for the read/write operation. As a subsequent command is determined, its location is again entered into the position queue, overwriting the previous command location.

Abstract: A circuit external to a memory controller in a processing system places a dynamic random access memory into a self-refresh state in response to a predetermined condition associated with a power-down or reset event.

Abstract: An apparatus is provided for surface-based data mapping for a disk drive system and a method of operation in which adjacent data tracks on the data storage surfaces of a disk drive are grouped into data track sets and data track sets on different data storage surfaces are grouped into bunches. The bunches are used to determine how to perform the logical to physical data layout mapping inside the disk drive. A disk drive controller controls disk read/write heads and provides a data layout mapping that maps logically adjacent data blocks to a data track, then to an adjacent data track radially along the same surface in a data track set in a bunch, and then to a different data track in a different data track set in the bunch.

Abstract: A storage virtualization selection technique “automates” a virtualization selection process to create virtual disk (vdisk) storage objects over a volume of a file system implemented by a storage operating system of a multi-protocol storage appliance. The file system provides a virtualization system that aggregates physical storage of a set of disks or portions (e.g., extents) of disks into a pool of blocks that can be dynamically allocated to form a vdisk. The file system also provides reliability guarantees for the vdisks in accordance with its underlying architecture. That is, the file system organizes its storage within volumes created among the managed disks. The vdisk is thereafter created as a storage object within a volume and, thus, inherits the underlying reliability configuration associated with that volume.

Abstract: The present invention provides an integrated controller to process both optical reads and optical writes of multiple optical media. The integrated controller includes a host interface; a buffer manager coupled to the host interface; an embedded memory coupled to the buffer manager; an integrated encoding/decoding engine coupled to the buffer manager; a data channel interface coupled to the integrated encoding/decoding engine; and an integrated servo/recording processor coupled to the integrated encoding/decoding engine and the data channel interface, where the integrated servo/recording processor includes a set of write strategies. The present invention provides a controller which integrates the functionality of the conventional controllers into an integrated processor. With the controller in accordance with the present invention, a single drive may be provided which can read CD-based and DVD-based formats, read and write to Write Once Media, and read and write to Rewritable Media.

Abstract: The invention may be embodied in a method and a related computer system. The computer system includes a host computer with a native drive-access routine having a limited address range, and a disk drive with a protected area that is inaccessible to a user's preferred operating system. The protected area also lies beyond the limited address range. The method includes receiving and detecting a command in the disk drive for reading a master boot record to initiate a bootload of the operating system. In response to detecting the command, the method includes transferring a drive-selected master boot record that, when executed in the computer system, initiates a process that enables address spoofing, loads an extended-address drive-access routine from the protected area using spoofed addresses within the limited address range, and executes the extended-address drive-access routine to replace the native drive-access routine for providing access to the protected area.

Abstract: A high availability storage system is provided in a server. The server includes a plurality of storage controllers. The storage controllers may be connected to storage enclosures that house the physical devices. If one controller fails, the second controller assumes command of the drive array handled by the failed controller with no interruption of server operation or loss of data. The controllers are connected to the physical drives via a channel or bus, such as a small computer systems interface bus. When two or more teaming controllers are active, the channel or bus may be split to increase throughput. A team driver is provided to direct and redirect requests to the appropriate controllers. The team drive may detect a failed controller, rejoin the bus, and assign control of all logical or physical drives to the remaining active controller. The team driver may also detect a new controller being added to the system, slit the bus, and divide the logical drives between the teaming controllers.

Abstract: A disk device controller (1) performs reading/writing of data and management information from/to a first disk device (4) and a second disk device (5). The first disk device (4) and the second disk device (5) hold their device information and storing the management information and the data from the disk device controller (1). A reference device information holder (3) holds previously set reference device information peculiar to the device. A master disk decider (2) decides which one of the first disk device (4) and the second disk device is the master disk, based on the device information and the management information held in the first disk device (4) and the second disk device (5), and the reference device information held in the reference device information holder (3).

Abstract: When writing to a hard disk drive, an effective track skew is used which differs from the track skew used when reading from the disk. During reads from the disk, the disk controller uses a traditional logical track layout and logical block address (LBA) numbering having a track skew value related to read settle time. A different effective track skew value, optimized for write settle time, is used, however, when writing to the disk. Logical blocks are written to the disk out-of-sequence in order to accommodate this different effective track skew value.

Abstract: A disk array control device includes a plurality of channel interface (IF) units, a plurality of disk IF units, a cache memory unit, and a shared memory unit. The connection system between the plurality of channel IF units and plurality of disk IF units and the cache memory unit is different from the connection system between the plurality of channel IF units and plurality of disk IF units and the shared memory unit. In the invention, the plurality of channel IF units and the plurality of disk IF units are connected via a selector to the cache memory unit whereas the plurality of channel IF units and the plurality of disk IF units are directly connected to the shared memory unit with no selectors.

Abstract: A computer system for multi-type DRAM support includes a first slot for receiving a first type DRAM, a second slot for receiving a second type DRAM, a north bridge chip, and a control circuit. The first slot includes a plurality of first slot pins, and each of them corresponds to a first pin assignment. The second slot includes a plurality of second slot pins, and each of them corresponds to a second pin assignment. The north bridge chip includes a plurality of chip pins, and each of them corresponds to a first and second pin assignment. When the control circuit generates a first control signal, the pin assignments of the chip pins are defined as the first pin assignments. When the control circuit generates a second control signal, the pin assignments of the chip pins are defined as the second pin assignments.

Abstract: A hard drive optimization function is provided to the set-up utility of the basic input/output service (BIOS) of a computer system. When executed, the optimization function benchmarks the hard drive's overall performance with sequential accesses for a number of transfer block sizes, employing various access block sizes for each transfer block size. In one embodiment, the optimization function determines the optimal transfer block size by comparing the average throughput (kbytes/sec) for the transfer block sizes examined. The average throughput for each transfer block size is determined through a number of sequential accesses made using the access block sizes. The access block sizes are systematically synthesized in accordance to a number of benchmarking parameters.

Abstract: A virtual sequential data storage (VSDS) system includes a VSDS controller coupled to physical data storage and a host machine with at least one host application. The controller is configured to carry out commands from the host application referencing VSDS. A router installed at the host intercepts prescribed types of host application commands directed to the controller. For each intercepted read/write command, the router determines a target physical location in physical data storage to carry out the intercepted host read/write command. Also, if the host application command is a read command, the router transfers data requested by the read command from the target physical location to the host application bypassing the controller. If the host application command is a write command, the router transfers write data associated with the write command from the host application to the target physical location bypassing the controller.

Abstract: In accordance with the invention, a system and method for further enhancing the transfer efficiency of the disk is provided. In an aspect of the invention, a hierarchical data structure for storing a portion of data in a data file is provided. The data structure includes a granule storage unit that is configured to store individual bits of data, a randomly sized component data unit that is configured to group a sequence of granules as a related data unit, and an extent transfer unit that is configured to group at least one component data unit as a data file. The granule storage unit may include at least one header granule and at least one data granule. The header granule includes metadata information relating to the component data unit.

Abstract: A storage subsystem includes a disk control unit having a cache memory and disk units under control thereof is connected to a central processing unit through an interface such as FC-SB2 which the central processing unit issues an I/O request including a chain of plural commands and data asynchronously with responses from the disk control unit. The disk control unit executes commands having target data hit on the cache memory independently of the order of receipt of plural commands from the central processing unit, in parallel with the staging of target data of commands resulting in cache misses from a disk unit to the cache memory.

Abstract: An optimizing tool optimizes a computer system's page space by basing the page size on the amount of real memory in the computer system. The optimization tool determines the amount of real memory in the computer system. The amount of memory is multiplied by a multiplier to determine an optimal amount of page space to allocate. In one embodiment the multiplier used is two (2) so that the amount of page space is double the amount of real memory. The optimal page space is compared with the amount of page space currently allocated in the computer system. If more page space is needed, the optimization tool determines where on the computer system's disk space the additional page space should be added. In a UNIX embodiment, the optimization tool determines whether a non-root volume group exists on the system. A non-root group without a paging space is examined for a new paging space addition. If a non-root group is found, the paging space needed is added to the non-root group.

Abstract: A method for writing a file of data to a compact disc media is provided. The method begins by receiving a first portion of the file for writing to the compact disc media. The first portion can be any portion of the file. Once received, the first portion is divided into a plurality of chunks. A map data sector is then generated for a set of the plurality of chunks, and the map data sector includes information for interrelating the file data and the plurality of chunks to be written to the compact disc media. The map data sector is then written to the compact disc media followed by the plurality of chunks of the first portion of the file. If possible, the plurality of chunks are first compressed before writing to the compact disc media. If the first portion is long enough to fill multiple sets of chunks, associated map data sectors will be generated for those additional sets of chunks.

Abstract: In a control apparatus for operating with program data, it is possible to alter the operation of a control circuit by rewriting the data of the program memory built in an LSI, with ease and at a low cost independently of the operation of the control circuit. For that purpose, the control apparatus includes a ROM, a SRAM, a means for writing data in the SRAM, a selection means for selecting the output from the ROM or the SRAM in accordance with the addresses supplied to the ROM and the SRAM, and a control means for outputting the addresses to the ROM and the SRAM and operating with the output from the selection means as program data.

Abstract: A process performs an intra-disk swap. The process includes finding a set of values indicative of access loads of new states of a disk. Each new state is produced from a current state of the disk by hypothetically swapping a pair of physical storage volumes of the disk. The process also includes performing the swap of a pair of physical storage volumes based on the value of the access load of the new state produced by hypothetically swapping the pair.

Abstract: Data states of storage apparatuses are managed. When a storage apparatus is allocated from a storage pool to a computer, management information written in the storage apparatus is erased if the data state of the storage apparatus is unknown. When the storage apparatus becomes unnecessary and is restored to the storage pool, the management information is also erased. Further, when the storage apparatus is allocated to the computer, a level of confidentiality is set. When the storage apparatus is restored to the storage pool, data in the storage apparatus is automatically erased according to the set level of confidentiality.

Abstract: Disclosed are a memory command address system and a memory module that can be operated not only for 266 MHzCLK but also for 200 MHzCLK, in which clock timings in the input sections of a PLL, a register, and a DRAM are matched to one another, a DLL (delay locked loop) is provided in the register, the output timing of CA signal from the register is controlled so that the setup time margin and the hold time margin of the CA signal with respect to the clock signal with the additional latency in the DRAM=1.5 or 2.0 are equated to each other, such that clock operation of 266 MHz, for example, is made possible. If both 266 MHz and 200 MHz are used, by taking account of the timing budget, control is made for retarding the timing of the CA signal input to the flip-flop which receives an internal clock signal (intCLK) supplied to the flip-flop for determining the CA signal output timing from the register.

Abstract: A set of storage disks includes a mirrored pair of disks. Each disk in the pair includes a mirror copy of data stored on the other disk in the pair. For each of the disks in the pair, the data forming the mirror copy is physically located between the center of the disk and the data that is mirrored on the other disk.

Abstract: The invention includes a disk drive that includes a controller that is connected to a physical media. The controller includes a processor that is connected a controller memory. The disk drive is responsive to communication from a host computer. The controller memory includes a set of computer program instructions and data to write data to the disk drive memory as a linear sequence of data bytes in response to a write data command from the computer. In yet other embodiments, the invention uses hardware data compression to compress data before it is written to a disk drive, and to decompress data before compressed data is returned to a computer.

Abstract: An information storage medium is designed to assure stable continuous recording without adverse effect, even when many defective areas are present on the information storage medium. To record information onto the information storage medium, a file unit is defined as a first unit. A contiguous data area unit to be treated as a continuous recording area is defined as a second unit. Furthermore, recording is done in the contiguous data area units and a collection of the contiguous data area units is organized into the file unit. In addition, an information recording place is provided in such a manner that the contiguous data area unit is so set that it extends over the recording area of another file already recorded on the information storage medium and a defective area on the information storage medium.