DDD

dynamic array block. A data structure used to manage dynamic arrays.

digital audio tape.

Numbers, characters, images, or other method of recording, in a form which can be input into a computer, stored and processed there, or transmitted on some digital channel.

The part of a Macintosh file that contains information (data) specified by the user. A Macintosh file contains two parts, the data fork and the resource fork.

The second of seven layers of the OSI reference model. The data-link layer is involved in packaging and addressing information, and controlling the flow of separate transmissions over communication lines.

The transfer of inactive data from a NetWare volume to tape, optical disk, or other near-line or offline storage media. Data migration lets an administrator move data to a storage device, while NetWare still sees the data as residing on the volume.

A set of files or records containing logically related information. The database is managed by a database application, which provides organization for and access to the files or records.

A data transmission packet used in connectionless mode communication. Datagrams are independent of each other in that the receiver is able to reconstruct a message without any dependency on the order in which packets are received. In general, datagrams are not acknowledged.

double-byte character set. A character set that uses two bytes to represent a single character (unlike ASCII, which uses one byte per character). DBCS’s are used for non-Roman alphabets such as Japanese, Chinese, and Korean.

Dynamic Data Exchange. The message protocol in Microsoft Windows that allows applications to request and exchange data.

1. A situation that occurs when two or more nodes are waiting for messages from each other and cannot continue processing verbs; when two or more applications attempt to lock the same files.

2. A condition that occurs when two tasks are retrying operations on files, pages, or records that one has already locked.

To remove errors from a program.

A screen that displays information useful in debugging programs. This screen can be accessed from within an assembly or C program or by means of a special key sequence. This screen is hidden unless the server is at a breakpoint.

A tool used by developers to identify errors in a program in order to facilitate their removal.

The unscrambling or decoding of encrypted data.

A preset option or value used by the computer until it is specifically changed by a user.

A file containing standard linking information about an NLM, such as the names of the object files to link and the name of the executable to create. It also includes a list of functions that the NLM wants to import or export. The definition file consists of keywords which direct the NetWare linker in creating the executable.

An object-oriented application development system for Windows based on Object Pascal. Delphi includes visual programming tools and creates .exe files.

directory entry table. A table on every network volume that contains directory entries for each file on the volume. The table, stored in the server's memory, enables quick access to the location of every file.

A person who creates software, either for internal use or for commercial sale.

A mechanical, electrical, or electronic peripheral with a specific purpose. For example, a printer or mouse, or, in AS/400, a synonym for logical unit (LU).

The software or firmware that translates OS requests (such as I/O requests) into a format that is recognizable by specific hardware, such as adapters, hard disks, or network boards.

direct file system. An interface that enables developers to access the file system at a low level. This interface is useful for such applications as databases and backup utilities.

Directory Information Base. The database, prior to NetWare 4.11, that was used for storing NDS configuration information. With NetWare 4.11 this database was called "Directory database." With NetWare 5 it was changed to "NDS database."

DVD. A high-capacity disk format that is the same size as a CD-ROM (5 inches in diameter), but is capable of holding between 4.7 and 17 gigabytes (compared to about 650 megabytes for a CD-ROM). The capacity of a DVD is determined by whether one or two substrates are used, and by whether information is recorded on one or two sides of the disk.

A recordable digital video disk (DVD-R) can store 3.8 gigabytes per side.

DFS. An interface that enables developers to access the file system at a low level. This interface is useful for such applications as databases and backup utilities.

DMA. A circuit that assists the transfer of information between a device and system memory. It is managed by a special processor.

A collection of files and other subdirectories. Directories are information containers, like files. However, instead of text or other data, directories contain files and other directories. In addition, directories are hierarchically organized; that is, a directory has a parent directory "above" and may also have subdirectories "below." Similarly, each subdirectory can contain other files and also can have more subdirectories. Because they are hierarchically organized, directories provide a logical way to organize files.

The area of server memory where the most often requested directory entries are copied from disk directory tables. The file cache reduces the time it takes to determine a file’s location on the disk.

Information in a server's DET that pertains to a single file or directory, including the name, owner, date and time or last update, first six trustee assignments, and location of the fist data block.

DET. A table on every network volume that contains directory entries for each file on the volume. The table, stored in the server's memory, enables quick access to the location of every file.

DIB. The database, prior to NetWare 4.11, that was used for storing NDS configuration information. With NetWare 4.11 this database was called "Directory database." With NetWare 5 it was changed to "NDS database."

An addressable entity on a network that contains information about a directory. It is a 128-byte entry found in the DET maintained by a server.

Contains information about a directory: directory name, attributes, inherited rights mask, creation date and time, creator’s object ID, a link to the parent directory, and a link to a trustee node (if one exists). It also includes a name space indicator, last archived date and time, last modification date and time, up to 8 trustee object IDs, up to 8 trustee rights masks. See also file node and trustee node.

The full specification that includes server name, volume name, and name of each directory leading to the file system directory you need to access. The position of a file within the file system is its directory path.

See NDS.

A table that contains basic information about files, directories, directory trustees, or other entities on the volume.

In NDS, the hierarchical structure of objects in the NDS database, called the NDS tree. The NDS tree includes container objects that are used to organize the network and leaf objects that represent resources.

File blocks in memory waiting to be written to disk.

The technology that allows an application-specific database to share selected data with NDS eDirectory and to keep modifications to that data synchronized with both NDS and the database.

A data storage unit used by a volume. Disk allocation blocks come in five sizes: 4 KB, 8 KB, 16 KB, 32 KB, and 64 KB. Disk allocation block sizes can vary from volume to volume; however, one volume can have only one block size. A disk allocation block represents the smallest file size for that volume.

An area of RAM used to store data accessed frequently from disk. Caches are very useful for increasing the performance of applications that have to access a lot of data from disk, like databases and spreadsheets.

To present on the monitor screen.

DN. The complete name, or path, from an object to the [Root] of the Directory tree.

dynamic link library. A set of related program routines and data that is used by applications at run-time that can be used as a common resource by many programs.

direct memory access. A circuit that assists the transfer of information between a device and system memory. It is managed by a special processor.

distinguished name. The complete name, or path, from an object to the [Root] of the Directory tree.

Domain Name System. A distributed database system that provides name-to-IP address mapping for computers on an internetwork or on the Internet.

distributed object management. An object-oriented network management design.

DNS. A distributed database system that provides name-to-IP address mapping for computers on an internetwork or on the Internet.

Software that oversees disk I/O, video support, keyboard control, and internal commands. A computer needs a disk operating system to function.

Short for "physical drive." A storage device that data is written to and read from, such as a disk drive or tape drive. A drive that is physically contained in or attached to a workstation is called a local drive.

Short for "logical drive." An identification for a specific directory located on a disk drive. For example, network drives point to a directory on the network rather than to a local disk.

In SFT III, the treatment of disk drives on separate, mirrored servers, as duplexed partitions on a single server. If one server goes down, the remaining server is able to continue fulfilling requests from clients. When the server is brought up again, the drives are remirrored in the background.

A software module that manages the operation of a specific device or protocol and provides services to modules running above it. Drivers allow higher-level modules, such as applications, to be device- and protocol-independent (able to run on any device or protocol for which a driver is available).

digital video disk. A high-capacity disk format that is the same size as a CD-ROM (5 inches in diameter), but is capable of holding between 4.7 and 17 gigabytes (compared to about 650 megabytes for a CD-ROM). The capacity of a DVD is determined by whether one or two substrates are used, and by whether information is recorded on one or two sides of the disk.

A recordable digital video disk (DVD-R) can store 3.8 gigabytes per side.

An array that can grow as a program runs. A dynamic array has no fixed size.

DAB. A data structure used to manage dynamic arrays.

DDE. The message protocol in Microsoft Windows that allows applications to request and exchange data.

DLL. A set of related program routines and data that is used by applications at run-time that can be used as a common resource by many programs.

A bindery object that is created and deleted frequently, for example, objects placed in the bindery by SAP. Dynamic objects disappear from the bindery when the server is restarted. See also bindery and static object.