Abstract: High level commands for a disk drive are processed by a task manager program that parses them into low level subcommands (e.g., SCSI commands). The low level subcommands are. then presented to the command execution means of the disk drive for execution. The parsing or sub tasking of a high level command into a number of low level commands permits the efficient handling of subcommands that must be deferred until other subcommands are executed and of third party XOR operations.

Abstract: A disk drive that is enabled by information contained in a mode page and in a command to access data blocks of either a small size (e.g., 512 bytes) or of a large size (e.g., 4,096 bytes). This allows legacy application software written for 512 byte sized blocks to run without change. By turning on the 4,096 byte sized block flag in the command, new software written to obtain improved performance benefits may also be used with the disk drive. The dual block capability is implemented in software.

Abstract: Disclosed is a method and device adapter for managing devices in a data processing system that includes a plurality of device adapters connected for independent communication with at least one shared device (e.g. disk data storage device). The method comprises the steps of: issuing a command from a first of the plurality of adapters to the at least one shared device; setting, in the first adapter, first and second timeouts associated with the command; on expiration of the first timeout value, issuing a message from said first adapter to other(s) of the plurality of adapters to request the other adapter(s) to notify the first adapter of any work requested of the shared device by the other adapter(s); and on expiration of the second timeout value, initiating a recovery operation in the data processing system.

Abstract: A method of changing the operating system in a computer system by using an address offset mode (AOM) feature for the address space of a hard disk drive connected to the computer system. Initialization of the computer loads the first operating system (OS) from a user area in the disk drive address space. An enable AOM command offsets the disk drive address space and reinitializes the computer to load a second OS from a reserve space in the disk drive address space. A command setting the maximum size of the address space of the hard disk drive provides a wrap around feature allowing the entire address space of the disk drive to be addressable for diagnostics or updating purposes. The computer is returned to operation with the first OS by a disable AOM command, or alternatively, by a power on reset, a software reset or a hardware reset. The method of changing operating systems is coded in the hard disk drive and does not require additions or modifications to the memory or the BIOS ROM of the computer system.

Abstract: A coil assembly for disk drive components is presented which includes a coil winding free of lubricants that cause stiction problems during the operation of the disk drive assembly. An actuator coil and spindle motor winding are disclosed which include a conductor, an insulating layer over the conductor, a bond coat overlying the insulating layer, and a lubricant coating on the insulating layer. The lubricant coating is a hydrocarbon based oil having a molecular weight within ranges that will not volatilize and condense on the surface of the disks in the drive.

Abstract: A multi-track density direct access storage device is disclosed. In accordance with a preferred embodiment of the present invention, a direct access storage device for data storage within a data processing system comprises a housing, a rotatable spindle, at least one disk, and several heads. The disk is fixedly mounted to the rotatable spindle, and the rotatable spindle is rotated by a motor within the housing. A first disk surface of the disk has a first track density and a second disk surface of the disk has a second track density; wherein the second track density is preferably greater than the first track density. Each of the several heads contains a transducer to read and write information from and to the disk during the disk rotation.

Abstract: The present invention provides a digital filter which is capable of preventing filter outputs from being discontinuous when a filter characteristic is changed. Initially, a servo assistant (SA) computes parameters for computing servo data, and based on the computed parameters, the SA judges an operating mode. If the mode has been changed, the SA will advance in processing. Next, the parameters of a filter are changed in correspondence with the judged operating mode, and the initial values of the interior variables of the filter are set to appropriate values.

Abstract: The present invention provides a retract circuit for a disk drive storage device that increases the reliability of a disk drive, and reduces the manufacturing cost. If the power supply of the disk drive is turned off, the retract circuit receives the current due to a back electromotive force from a spindle motor and clips it to a predetermined value or below, and supplies the current equal to or smaller than the predetermined value to the voice coil of a VCM. Then, the VCM drives a carriage, which swings to retract a head slider to the landing area of the disk. If the power is turned off, an FET transistor is turned on, and the current due to the back electromotive force is supplied to the voice coil via the FET transistor, a resistor, and a second FET. If the current due to the back electromotive force exceeds a predetermined value depending on the value of the resistor, two transistors are turned on.

Abstract: A system and method for organizing compressed data and uncompressed data in a storage system. The method and system include a compressor for compressing a data block into a compressed data block, wherein N represents a compression ratio. The storage disk includes a first disk partition having N slots for storing compressed data, and a second disk partition for storing uncompressed data. A portion of the N slots in the first partition include address pointers for pointing to locations in the second disk partition containing the uncompressed data.

Abstract: A method of mapping pixel IDs between X servers that differ in the format of pixel IDs they support is disclosed. The method involves defining a specific type of map for each master/participant pair, thus allowing X servers that support different formats to participate in one conference and to view colors that are as close to the application's request as each X server deems possible. A method of supporting applications that are dependent on mathematical operations on pixel values by an X Windows conferencing enabler is further disclosed. The mathematical operations on pixel values are common among X Windows applications that are color intensive, such as scientific visualization programs. This method allows these applications to be displayed with colors that are as close as the supports to the colors requested by the application as supported by the X server.

Abstract: Disclosed is a device adapter for controlling devices in a network comprising computer processor nodes and one or more devices, the device adapter having means for determining whether or not a device state has changed after a failure. Responsive to a determination that the device state has not changed, the adapter communicates with other device adapters in the network to reestablish permissions before resubmitting I/O requests. Responsive to a determination that the device state has changed after a failure, the adapter reintegrates itself with the other device adapters in the network before reprocessing work as necessary.

Abstract: A method and system for path management of data processing in an environment which includes a plurality of hosts running multiple operating systems is disclosed. The method and system includes providing a portable path management code and providing a plurality of control modules. Each of the control modules has an area which can only be accessed by the portable path management code. The method and system also include providing an interface to at least one device driver from the portable management code to allow the portable management code to control access to plurality of paths to a plurality of storage subsystems by the at least one device driver. The method and system in accordance with the present invention can provide path load balancing and fail over for a plurality of paths to a plurality of storage subsystems. The path management code is portable and platform independent so that the functionality can be ported easily to each operating system in the multiple system environment.

Abstract: Aspects for read/write data sharing of DASD (direct access storage device) data in a cluster of multiple data processing systems are described. In a method aspect, the method includes utilizing a first system as a managing system for file data modification of at least one file system, the at least one file system including a byte file system. The method further includes controlling access by at least one second system within the cluster of multiple system to data of the at least one file system through global token management, wherein concurrent, direct DASD read/write sharing of data of the at least one file system across the cluster of multiple systems occurs.

Abstract: Method and system aspects for supporting hierarchical file system management functions across multiple operating system platforms in a data processing system are provided. In these aspects, a code base provides predetermined functionality for each of a plurality of operating system platforms of the data processing system. Further, a common kernel extension is utilized by the code base, with the common kernel extension supporting a hierarchical file system of the data processing system. The common kernel extension supports file system intervention in the hierarchical file system by handling an interface between each operating system platform and a file system. Also, the common kernel extension further handles an interface between each operating system platform and a device driver.

Abstract: A method and system are disclosed for controlling the application of a reset voltage pulse to a GMR sensor in a direct-access storage device (DASD), such that existing data is not damaged or altered. Each sensor is positioned or parked at a location reserved for reset pulse application, where no valid data is stored. A complex interrelated set of commands is then initiated, and upon completion of the entire set of interrelated commands, a reset pulse is applied to the GMR sensor. Any variation or interruption in the complex interrelated set of commands will result in a disarming of the reset pulse circuitry, effectively preventing an accidental or inadvertent application of the GMR reset pulse. Alternately, a group of GMR sensors each may be tracked to a reserve track, forming a reserve cylinder. Servo marks on the reserve track are sensed by a selected sensor and utilized to ensure no valid data is present.

Abstract: The present invention provides a system and method for expanding and collapsing a tree view from a web interface by using HTML to build the visual representation of the web server's information structure, which has the capability to preserve previous tree expansion states in the stateless web HTML environment. In a method according to the present invention, a request comes in from a client browser which contains a universal resource locator (URL). The web server passes the URL to the tree HTML page generation engine to generate the collapsible/expandable tree. The tree HTML page generation engine server will call the corresponding query modules according to the information passed in from the URL. A linked list is generated according to the results returned from one of the query modules. The linked list is then passed into the tree HTML page generation engine. The tree HTML page generation engine generates the HTML page containing nodes.

Abstract: In a computer-implemented process, a task requiring access to a database uses an object-oriented class to enable one database connection for the duration of the task, avoiding multiple and concurrent database connections, thus allowing a more efficient use of the database connection.

Abstract: A method and system for accessing log messages in a distributed network is disclosed. In a first aspect, the method and system comprise selecting a plurality of application log messages from a manager within the network and displaying the plurality of log messages via a browser user interface in the first window. In a second aspect, the method and system further includes selecting a particular log message from the plurality of log messages and displaying help-text related to the selected particular log message via the browser user interface. In summary, a method and system for providing easy access to Help text regarding application log messages in a browser user interface displays application log messages on a Java applet panel within the browser. When the user double-clicks on a message, a new Web browser window is displayed which includes an HTML page with the message text, a detailed explanation of the message, and the recommend user response.

Abstract: In a computer system including a disk controller and a disk drive, the disk controller determines whether to issue a command to the disk drive by considering both a priority level associated with the command, and a pending workload of the disk drive.

Abstract: The present invention provides a method and apparatus for moving a head arm assembly to a landing zone in a disk drive storage device. In disk drive according to the present invention, a control means responds to termination of a read/write operation by applying a drive current for moving an actuator arm toward an actuator lock, and then continuously applies the drive current to the actuating means to maintain an engagement of the actuator arm with the actuator lock stopped at a predetermined position, after the termination of read/write operation, and then stops a rotation of said rotating data recording disk.