Glossary

Absolute frames. These frames do not change, since no data is stored within them. The ABS area is where the D3 virtual (operating system) code resides.

The ACCESS Query Language (AQL) is a D3 facility used to retrieve and output data and consists of the List preprocessor, the Select processor, and the Output processor. AQL is a system-level information retrieval language that allows users to query their database without writing complex programs.

An account is a collection of logically related files. Each account has a master dictionary (MD), where the vocabulary for the account resides. This includes items such as commands, Procs, menus, macros, connectives, modifiers, file-defining items (D-pointers) and synonym-defining items (Q-pointers).

ACID is an acronym for Atomic, Compliant, Isolated, Durable.

An active list is a list of strings for use in a subsequent process that handles items one at a time. Typically, a list contains item-IDs for subsequent processing, but a list can actually contain anything. For example, the statement, select entity creates a list of item-IDs, while the statement, select entity name creates a list from the contents of each entity item’s name attribute.

ADI is an acronym for attribute-defining item.

Each server can be given an alias to avoid having to tie a D3 object to a given computer on the network. For example: When creating an accounting database, it is better to use an alias (such as Accounting) for the server name, rather than its physical network name.

AMC is an acronym for attribute mark count.

ASCII is an acronym for the set of characters that comprise the American Standard Code for Information Interchange.

The assembler changes Pick assembly language source statements (lines) into machine executable object code.

Pick assembly language defines the language of the Pick Virtual environment. It is used to write the Pick core functionalities.

Assembly languages are computer programming languages usually related to particular CPU’s primitives.

An atomic operation is an indivisible operation, either uninterruptible or, if aborted, a mechanism is provided that ensures the return of the system to its state prior to initiation of the operation.

An attribute is a field that is used to store data within an item.

An attribute mark is the specific metacharacter used in D3 items to indicate the end of an attribute, and the beginning of another.

B-tree is the balanced tree access method that D3 supports throughout the system and in every process that touches the database.

Backward link zero (BLZ) is a particular system error. A frame containing data, either workspace or file system data was not properly linked to a previous frame of data. Instead, this backward pointer was zero. The system was traversing data backward and ran off the beginning of the data.

Beginners All Purpose Symbolic Instruction Code (BASIC) is a third generation programming language originally developed at Dartmouth College in the early sixties. COBOL and the various forms of BASIC taken as a whole are the two most popular programming languages of all time.

Binary files are used to access binary items using normal D3 utilities.

Blocking I/O is the process that D3 uses to group several disk reads into one larger disk access in order to improve disk performance.

BLZ is an acronym for backward link zero.

Branching is a fundamental concept in programming and programming languages regarding the control of program execution.

CCB is an acronym for cursor control block.

CDS is an acronym for Cell Directory Service.

The clipboard is a temporary storage area where data can be placed from an application and later retrieved from the same or another application.

A command is a stored procedure that is inherent to one of the processors in D3.

Conversions are subroutines used to convert data to alternate formats. These are listed under Processing Codes.

Correlatives are used in attribute 8 of the dictionary item being processed by AQL or the Update processor.

CRT is an acronym for cathode ray tube, the display portion of almost all dumb terminals.

Cruising is the ability to scan forwards and backwards through items in a file.

The CTRL key is used to enter commands in the Update processor.

A cursor control block is a binary item that contains the codes and control strings pertinent to the terminal in question. Each system functions (@(-(n))) has its own array position, and the system cursor function searches this item for control strings such as clear-screen, clear to end of screen, and so on.

A D-pointer is used to define a file’s location.

A delimiter delineates parts of a statement, command, or data.

The dialer is a subsystem that allows D3 systems to communicate over serial lines to transfer items, execute commands on remote sites, and to synchronize databases by transferring updates.

Dictionaries are used by the D3 system to describe, define, locate, and, in general, operate on data within the files to which they point.

Dirty bits are status bytes associated with each item in the D3 file system indicating that the item is new or changed.

dm is an acronym for the D3 data manager account which contains the files necessary for basic system operation.

A Windows concept that defines a set of systems, clients, and servers that are administered as a unit. A domain controller is designated to handle the security.

Double-spacing AQL reports can be achieved using the dbl-spc modifier. To double-space Output processor documents, change the vertical motion index by using the .vmi Output processor command.

EBCDIC is an acronym for Extended Binary Coded Decimal Interchange Code.

A data element is an atomic datum variously known as field, attribute, value, attribute value, and so on.

An entity is a system element, such as a D3 process, a serial port, or a device, with which data can be exchanged.

An expression is a variable, literal, function, or expression enclosed in parentheses, or a combination of these, separated by operators.

External format describes data that has been externally converted using one of the conversion or processing codes provided with D3. As a general rule, external format means data is in a human-readable format.

FCB is an acronym for file control block.

FDI is an acronym for file-defining item.

FID is an acronym for frame-ID, which is the unique identifier to each virtual frame on the disk.

Everything in the D3 database is an item in a file.

Every file on the system has a special frame attached to it called a file control block or FCB. These frames contain information about the file, including index pointers and their compiled (algebraic) processing codes, the file D-pointer information for editing, pointers, and workspace used by the system when calling FlashBASIC subroutines from file dictionaries.

A file inconsistency is a state representing structural inconsistency within a certain group of a file.

The file inconsistency handler processes file inconsistencies encountered in the D3 file system.

Attributes 5 and 6 of file-defining items can contain retrieval and update lock codes respectively. These codes are used to restrict access to certain data files and master dictionaries. Lock codes are sets of characters used as codes. Multiple lock codes are separated by value marks. The first lock code (retrieval or update) in a master dictionary or file dictionary must be matched in attribute 6 (key) of the user’s item in the users file to allow access to the file or master dictionary. If the lock code does not match, access is denied.

A file name is the name of a D3 file.

The file reference is the name of a file in the master dictionary to which the user is currently logged. It can also be a synonym file name. The file name can be preceded by the literal word dict to access the dictionary of the file instead of the data portion of the file. The default is data. In some cases, data may be specified to indicate only the data portion of the file.

A D3 service, normally started automatically at boot time on a Windows server that services file system requests. Each D3 file server must have an FSI service or process started to be able to access the D3 tables.

File-defining items are the mechanisms by which the D3 system establishes the disk addresses of a file.

FlashBASIC is a high-level programming language that is an extension of the Dartmouth BASIC (Beginners All-purpose Symbolic Instruction Code) language. It is the principal programming language bundled with the D3 system and was designed for the implementation of application requirements not handled by standard D3 functionality.

The flusher is responsible for scheduling and writing all write-required (dirty) frames back to disk.

Font is the typeface of a character.

A frame is the basic storage area of the system. Each frame is addressed by its numeric frame ID (FID), beginning with frame 1, and ending at a frame called maxfid. Maxfid is determined by the actual size of the disk and the size of data frames.

Full duplex means simultaneous bidirectional communications. Both sides send and receive with virtually no turnaround time.

A full restore is the opposite of a full save or file-save. A full restore is the process of reloading the entire file system from either a file-save tape or from the original sys-gen media provided with your system.

A group is a partition in a file consisting of one or more linked frames used for storing and retrieving items.

Half duplex is communication in a single direction at a time.

A hangup is a condition by which a device, usually a modem or a network, indicates to the application that communication is no longer possible.

Hashing is the file-access method used by D3 to find items in a file.

Header files access header information using normal D3 utilities.

Hot Backup is a configuration where one machine is in a standby mode, ready to take over the load from a failing system. Starting with D3 9.0, Hot Backup now tests to confirm that a license has been purchased.

A port is considered hung when it refuses to accept keyboard input and is producing no new terminal output.

An incremental restore restores all items from the most recent incremental save tape.

An incremental save backs up only the items that have been changed since the last full save.

Installation information is provided in your System Installation Guide provided with your D3 system.

Internal format is the data format resulting when data is internally converted using one of the conversion or processing codes provided with D3. As a general rule, internal format refers to the manner in which data is stored inside the system.

An item is the fundamental directly accessible aggregation of data in D3.

An item-ID is a unique identifier by which an item can be retrieved from a file. An item-ID may be any length up to 100 characters. It can be made up of any characters except the system delimiters; sm, am, vm, svm, or sb, and any character with an ASCII value 247 or greater. If any of these reserved values are used in an item-ID, the item-ID will be truncated at the first use of such a character. It is recommended that characters with ASCII values greater than 127 not be used since they may not display or show as different symbols on different display or printing devices.

Language definition is the file structure that is used by D3 to perform case insensitive compares according to other language definitions.

Any command or program can be interrupted during execution by pressing the active level pushing key, (usually the BREAK or ESC key). When a command or program is interrupted, the system stops execution and saves all parameters so that execution can be resumed exactly where it was interrupted. When a process is interrupted at the normal system level, the system prompts with two colons. At this point the command or program is said to be pushed one level.

Linked or dynamic overflow are the additional frames attached to a file. As files expand and contract, additional frames are added to or removed from the groups in the primary file space. All of these extra frames are called linked or dynamic overflow and the number of frames is always changing.

D3 locks groups on a process basis. A port executing a program is locked from accessing items locked by the previous level.

See Retrieval and Update Locks.

The logon procedure is used to gain access to the system, and consists of a user prompt, which is usually:

Macros are used to execute one or more TCL commands and are stored in the master dictionary with the name of the macro as the item-ID.

The master dictionary (md) file contains commands, Procs, macros, menus, connectives, default attribute-defining items, and file-defining items [both local (D-pointers) and synonym (Q-pointers)].

The maxfid is the last addressable frame on the disk. The what command outputs the current maxfid.

Menus provide a selection of processing choices.

Metacharacters are used to reference one of the four reserved delimiters that D3 uses within its item structure.

A modulo designates the number of groups (measured in frames) in the primary file space, as indicated during the creation or reallocation of the file.

The Name service allows clients to locate the service they need without knowing where and how to reach the server providing the service. To perform this service, Name service hides the network location and network protocols behind a symbolic service identification. This mechanism makes the application independent from the details, allowing, for example, for redistributing the server application from one system to another without any change in the client applications.

This topic describes how to implement a full save/restore of one machine to another across a network, using tape-socket.

The Open Systems File interface (OSFI) provides a standard mechanism for handling nonfile entities as if they were standard D3 files.

An acronym for the Open Systems File interface

The overflow table is the area that contains a list of unused frames.

Account passwords can be used to limit the access to an account or to limit access to the system.

Performance monitoring is the process of using various tips, utilities, and performance monitoring tools that allow identifying possible bottlenecks in a given configuration.

A phantom process is a process that is initiated at a terminal and detaches itself from that terminal for execution independent of that terminal. It is processed as a background task and the results display on the initiating terminal when the process is complete.

PIB is an acronym for Process Identification Block. It is often used, inappropriately, to designate a D3 port number.

PIB status is a piece of data returned by the where command. The pibstat program is used to break the information down into the possible binary states.

Pick remote files are standard Pick files on a nonlocal Pick machine.

A Process ID (PID) uniquely identifies a UNIX process. On D3, each D3 process is a UNIX process, and, therefore, is assigned a PID by UNIX. D3 processes are usually identified by their D3 port number (from 0 to the maximum number of ports), as usual. It is sometimes necessary to identify the PID of a D3 process. The PIDs are displayed by the TCL commands list-users, pid, psr and by the UNIX command d3.

Pointer items are internal file place-keepers that point to the frame where the actual data resides.

For UNIX: Port is not always the same as the physical device, and can be thought of as the D3 port number.

A port number is the sequentially-assigned number associated with each physical line or process on the system. The number of ports is determined by issuing the where command with a z option.

Primary file space is the initial space set aside for a file and is specified as a number of frames in the create-file command. For instance, if a file data level is set aside using 11 frames as its modulo, it has 11 frames in its primary file space.

A primary list is an active list of item-IDs to be used in a subsequent process that processes them one at a time.

A prompt is a computer request for data entry.

Prompt characters are the characters displayed at input prompts. The number of prompt characters output is equivalent to the level a process is at.

A pseudo tape is a binary host file handled internally as a large floppy. Data is formatted in 512 byte sectors and accessed sequentially.

A Q-pointer defines a duplicate (synonym) name for an already existing file.

A QS-pointer defines a remote file that is saved as if it were local.

A restore refers to the loading (restoring) of data into the D3 file system from a backup media created by a save, or t-dump.

Restricted system access means that a user has been denied access to TCL. Users can be denied access to TCL by placing the character r in the options attribute (Attribute 9: Attribute type) of their item in the users file. When this restriction is active, users are returned to the system logon program when they exit a process by pressing the BREAK key, if it is enabled.

If any process, such as a TCL command or a FlashBASIC program is executed from an account that does not have retrieval and/or update privileges for a file, and then attempts to read and/or write to that file, the process terminates with an error message indicating that the file is access protected.

A scrubber is a mechanism that provides overflow protection in the event of a system halt.

Secondary lists are created using the s option with the select, sselect or get-list commands. Its is only used when running compare and copy commands.

D3 provides several levels of security, including:

A segment mark is the specific metacharacter used within D3 items. The segment mark is not actually part of data. Rather, it is used as an item delimiter, and is automatically appended to the end of an item when written to disk.

The selection processor is responsible for presenting items to the List processor based on processing the selection criteria.

A seq item alters the normal sort sequence of characters used by the ms (mask alter sort) processing code.

Whenever requesting a software change, please provide as much of the following information to Rocket as you can. This form can be mailed or faxed to Rocket. Software Change Requests can also be phoned into Rocket.

The start buffer mark is used to pad tape records to the length specified during the most recently executed tape attachment command.

A subvalue is a field used to store data within a value of an attribute within an item.

A subvalue mark is the specific metacharacter used within D3 items to indicate the end of a subvalue, and the beginning of another.

Super Q-pointers are extended Q-pointers used to access non-D3 and/or nonlocal files.

Also known as Q-pointers, synonym-defining items are used in account master dictionaries to point to other files. A Q-pointer is a file alias that defines a path to an existing file that resides in the system under another name, or in another account, or both. A Q-pointer can reference any file in the system, including those within the same account.

A table synonym or Q-pointer is a special record in a master dictionary or table dictionary that points to another table, either in the same database or not.

Sysbase refers to the first frame where data is stored on the disk.

System delimiters refer to:

System privileges determine which processes the user has access to or can invoke.

All processes that handle magnetic media are classified as tape handling commands. All references to media and tape mean the same thing. Control is returned to the calling program when the user quits from a parity error.

Tape socket defines a tape system across a network. This section is an introduction to the functionality of the tape over a network subsystem.

The transaction logger is a subsystem designed to write file system updates to another device.

Through the OSFI, it is possible to access UNIX files as if they were D3 items, using AQL, BASIC, FlashBASIC, and so on. This section describes the format of the Q-pointer, the file structure and the access rules.

User exits allow direct references to assembler routines known as modes. These are generally not needed for new applications and are provided primarily for backwards compatibility and specialty utilities that must access internal structures.

A user-ID identifies a user. User-IDs are found in the dm,users, file.

A value is the field used to store data within an attribute of an item.

A value mark is the specific metacharacter used within D3 items to indicate the end of a value, and the beginning of another.

The var file is a pseudo file that maps to the user’s TCL shell variables.

A virtual machine is a set of resources obtained from UNIX at initialization time that display the functions and characteristics of a D3 computer system, and are shared by several D3 processes.

Workgroup is a collection of systems on a network that work as peers.