“DAC” to “DVMA master”

DAC to DVMA master

(1) (n.) digital-to-analog converter.

(2) (n.) dual address cycle.

daemon

(n.) A process that runs in the background, handling commands that are delivered for remote command execution. Examples are the mailer daemon and the printer daemon.

database connection pool

(n.) A collection of database connections with which database clients obtain access to a database. As database clients release connections to their database, these connections are returned to the database collection pool for further use.

data bus

(n.) A group of signal lines (wires) that is used as a common pathway among multiple devices in a computer system.

dataless client

(n.) A client system that relies on a server system for its home directory, and on a local disk for its root directory and swap space. See also diskfull client, diskless client.

Data Link Provider Interface

(DLPI) (n.) The AT&T System V^TM Release 4 operating system STREAMS-based kernel-level interface that supports the services of the data-link layer for both connection-mode and connectionless-mode services.

data service

(n.) The combination of software and configuration files that enables an application to run without modification in a Sun^TM Cluster configuration. When running in a Sun Cluster configuration, an application runs as a highly available resource under the control of the Resource Group Manager (RGM).

Data Service Development Library

(DSDL) (n.) A set of library functions that encapsulate the low-level Resource Management API and process-management functionality at a higher level. These library functions also add functionality to ease the writing of callback methods. See also Resource Management API.

data transfer bus

(DTB) (n.) A part of the VMEbus specification that contains data and address pathways and associated control signals. Functional modules that are called “DTB masters” and “DTB slaves” use the DTB to transfer data between each other.

DDI

See device driver interface.

deadlock

(n.) A situation that describes two or more processes that are waiting for another process to free a resource which is required to proceed. Also called deadly embrace.

debugger

(n.) A program for locating operational errors in another program. The debugger usually enables the developer to proceed stepwise through the malfunctioning portion of the program to examine data and check operational conditions.

decoder

(n.) A facility that decompresses data that has been encoded or compressed by an encoder. A decoder can be implemented in hardware, software, or a combination of both.

default master

(n.) The default cluster member on which a failover resource is brought online.

definition

(1) (n.) In imaging, distinctness or clarity of detail or outline in an image reproduction.

(2) (n.) In programming, a declaration that reserves storage (for data) or provides implementation (for methods).

dejagging

(n.) Obsolete term for anti-aliasing.

delegation

A principal (generally the context initiator) that, if permitted by the underlying security mechanism, can designate a peer principal (usually the context acceptor) as a proxy. A delegation designates a proxy by delegating its credentials to the peer. The delegated credentials can be used by the recipient to make requests on behalf of the original principal. This situation might happen when a principal uses the rlogin command from machine to machine to machine.

delimiter

(1) (n.) A value that separates and organizes items of data.

(2) (n.) A character that logically separates words or arguments on a command line. Two frequently used delimiters in the UNIX® system are the space and the tab.

deprecation

(n.) A reference to a class, interface, constructor, method, or field that is no longer recommended, and which might not be included in a future version of a product.

descriptor

(n.) A data structure that uniquely identifies a hardware device or software function.

deselect

(v.) In a window system, to remove the highlighting or some other visual cue from a previously selected object, such as removing the highlighting from an item in a list. If a widget is deselected, it is turned off.

deskside

(n.) A system enclosure that stands next to the user's desk. Contrast with desktop.

desktop

(n.) An entire system that fits on the top of the desk. Contrast with deskside. See also workspace.

device

(n.) A hardware component, such as a printer or disk drive, acting as a unit to perform a specific function.

device-dependent

(adj.) Characteristic of software that has been written for a specific computer device, and runs on that device exclusively. Software that can run only on a specific vendor's computer is called vendor dependent. Contrast with device-independent.

device driver

(n.) The software that converts device-independent graphics commands into device-specific (device-dependent) display.

device driver interface

(DDI) (n.) An interface that facilitates driver portability across different UNIX® system versions on SPARC^TM hardware.

device group

(n.) In a Sun^TM Cluster configuration, a user-defined group of device resources, such as disks, that can be mastered from different nodes in a cluster HA configuration. This group can include device resources of disks, Solaris^TM Volume Manager disk groups, and VERITAS Volume Manager disk groups.

device ID

(n.) In a Sun^TM Cluster configuration, a mechanism of identifying devices that are made available through the Solaris^TM Operating System. Device IDs are described in the devid_get(3DEVID) man page.

The Sun Cluster DID driver uses device IDs to determine correlation between the Solaris logical names on different cluster nodes. The DID driver probes each device for its device ID. If that device ID matches another device somewhere else in the cluster, both devices are given the same DID name. If the device ID hasn't been seen in the cluster before, a new DID name is assigned. See also DID driver.

device-independent

(adj.) Characteristic of software that has been written expressly for portability across dissimilar computer systems. An industry-standard graphics library, such as Programmer's Hierarchical Interactive Graphics System (PHIGS), is a device-independent interface. Contrast with device-dependent.

device name

(n.) The name that the system uses to identify a device. For example, /dev/rst0 (or just rst0) is the device name for 0.25-inch tape.

DGA

See direct graphics access.

dialog box

(n.) A secondary window that is displayed by an application to gather information from users or to inform them of a condition. A dialog box can contain panes, lists, buttons, and other components. In the Java^TM look and feel, dialog boxes are created by using the JDialog component. See also alert box, color chooser, palette window, secondary window, utility window.

diamond key

(n.) See meta key.

DID driver

(n.) In a Sun^TM Cluster configuration, a driver that is implemented by Sun Cluster software and is used to provide a consistent device namespace across the cluster. See also DID name.

DID name

(n.) In a Sun^TM Cluster configuration, a term that is used to identify global devices in a SunPlex^TM system. The DID name is a clustering identifier with a one-to-one or a one-to-many relationship with Solaris logical names. The format of the DID name is dXsY, where X is an integer and Y is the slice name.

differential archive

(n.) A Solaris Flash archive that contains only the differences between two system images, an unchanged master image and an updated master image. The differential archive contains files to be retained, modified, or deleted from the clone system. A differential update changes only the files specified and is restricted to systems that contain software consistent with the unchanged master image.

digital image

(n.) An image that has been converted into an array of pixels. See also digitize.

digitize

(1) (v.) To convert an image from hard copy (such as a photo) into digital (binary) data for display on a computer.

(2) (v.) To convert an analog signal (voltage or temperature) into a digital value.

direct graphics access

(DGA) (n.) A method of arbitrating access to the display between the XGL^TM library and an X11/NeWS^TM system server. This method enables the XGL library to “talk” directly to the frame buffer, which results in maximum performance.

direct memory access

(DMA) (n.) The transfer of data directly into memory without supervision of the processor. The data is passed on the bus directly between the memory and another device. Contrast with direct virtual memory access (DVMA).

directory

(n.) A file that contains other files and directories.

directory path name

(n.) The complete name by which the directory is known. The path name gives the sequence of directories by which the directory is linked to the root directory. Also called the directory name.

directory stack

(n.) A stack, implemented in the UNIX® C shell, that enables you to save frequently used directories and then jump quickly from one directory to another without typing the entire directory path.

direct virtual memory access

(DVMA) (n.) A mechanism to enable a device on the SBus to initiate data transfers between it and other SBus devices, such as system memory. Contrast with direct memory access.

dirty

(adj.) See 8-bit clean.

disc

(n.) An optical disc, as opposed to a magnetic disk, consistent with the common spelling that is used in the compact disc (CD) market. An example is a compact disc read-only memory (CD-ROM), which is an optical disc. See also disk.

disk

(n.) A round platter, or set of platters, of a magnetized medium organized into concentric tracks and sectors for storing data such as files. See also disc.

disk array

(n.) One or more physical disk drives that can form a single logical drive. For example, the SPARCstorage^TM Array Subsystem for Disk Expansion is a disk array. A disk array can contain several disk drive trays. See also composite drive, redundant array of independent discs (RAID).

disk device group

(n.) A disk group that is registered with Sun^TM Cluster software to be available to all cluster members.

disk path

In a Sun Cluster configuration, the connection between a cluster node and a physical disk or LUN storage device. The disk path includes the Solaris kernel driver stack, host bus adapter (HBA), and any intervening cables, switches, or network connectivity.

diskfull client

(n.) A client on a network that relies on a server for resources, such as files, but has its own local disk storage. Some of a diskfull client's files are local and other files are remote. The remote files can be obtained from any machine that runs as a network file server. Contrast with diskless client, standalone.

diskless client

(n.) A client on a network that relies on a server for all of its disk storage. Contrast with diskfull client, standalone.

disk partition

(n.) A portion of the disk that is reserved for a specific file system and function.

display

(v.) To present a display image on a display surface.

display device

(n.) The hardware device that displays windows, text, icons, and graphical images. Examples are a frame buffer and a monitor.

display function

(n.) See raster ops (ROP).

distributed

(adj.) Characteristic of running in more than one address space.

distributed file system

(n.) A file system that exists on more than one computer, enabling each user to access files on other computers.

Distributed Lock Manager

(DLM) (n.) The locking software that is used in a shared disk Oracle Parallel Server (OPS) environment. The DLM enables Oracle processes that are running on different nodes to synchronize database access. The DLM is designed for high availability. If a process or node crashes, the remaining nodes do not have to be shut down and restarted. A quick reconfiguration of the DLM is performed to recover from such a failure.

distribution

(n.) See software distribution.

DKI

See driver-kernel interface.

DMA

See direct memory access, direct virtual memory access.

DMP

(n.) Dynamic Multipathing.

domain name

(n.) The name that is assigned to a group of systems on a local network that share administrative files. A domain name is required for the Network Information Service (NIS) database to work properly.

dot file

(n.) See hidden file.

double-click

(v.) To click twice on a mouse button, accelerating a specific command's performance.

double-precision

(1) (adj.) Characteristic of using two native words of memory to store a numeric datum.

(2) (adj.) In the Java^TM language specification, characteristic of a floating-point number that holds 64 bits of data. See also single-precision.

downstream

(n.) In STREAMS, a direction of data that moves from the Stream head toward a driver. Also called output-side, write-side.

DR

(n.) dynamic reconfiguration.

drag

(v.) To move the mouse while holding down a mouse button. See also drag and drop.

drag and drop

(v.) To drag an interface element to a new location in order to move, copy, or link it. See also drag.

dragging

(n.) In a graphical user interface, moving all or part of a display group in a display space in such a way that the group continuously follows the pointer as though it were attached.

driver

(1) (n.) A software subsystem that controls either a hardware device (device driver) or another software subsystem.

(2) (n.) A STREAMS module that forms the Stream end. A driver can be a device driver or a pseudo-device driver. A driver is a required component in STREAMS (except in a STREAMS-based pipe mechanism), and is physically identical to a module. A driver typically handles data transfer between the kernel and a device and does almost no data processing.

driver kernel interface

(DKI) (n.) An interface between the UNIX® system kernel and different types of drivers. The DKI consists of a set of driver-defined functions that are called by the kernel. These functions are entry points into a driver.

drop

(v.) In a graphical user interface, to release the mouse button after grabbing an object. If the object is dropped in an appropriate area, an action is initiated. See also drag and drop, grab.

drop-down arrow

(n.) The triangular indicator that the user clicks to view more options than are visible on screen—such as the list that is attached to a combo box or the options that are provided by some toolbar buttons.

drop-down menu

(n.) A menu that is displayed when the user chooses a menu title in the menu bar. In Java^TM look and feel, drop-down menus are created by using the JMenu component. See also menu, menu bar.

DTB

See data transfer bus.

dual head

(n.) A single workstation with two monitors, generally operating so that a single cursor traverses both displays.

dual-partition upgrade

In a Sun Cluster configuration, a software upgrade method that uses the Sun Cluster Dual-Partition Software Swap feature to minimize service downtime during a cluster upgrade. In this method, the dual-partition software divides the cluster into two groups of nodes. One group of nodes continues services while the other group of nodes is upgraded. Then services are switched to the upgraded nodes and the remaining nodes are upgraded and rejoined to the cluster.

dump

(n.) A duplicate copy of files. See incremental dump.

DVMA

See direct virtual memory access.

DVMA cycle

An SBus cycle initiated by a direct virtual memory access (DVMA) master. A DVMA cycle consists of a translation cycle and a slave cycle.

DVMA master

(n.) An SBus master capable of initiating a bus cycle that uses the SBus controller to perform virtual address translation. In contrast, acentral processing unit (CPU) master has a private means for virtual address translation. A bus cycle initiated by a DVMA master consists of a translation cycle and a slave cycle.