HP OpenVMS Systems Documentation

Content starts here

OpenVMS User's Manual

Previous Contents Index

interactive utility: A computer program, invoked with a DCL command, that provides a special environment from which you can perform a specific set of tasks. You work interactively with these utilities by entering subcommands and other information in response to the utility's prompt.

iterative translation: The repetitive translation of a logical name that occurs when a logical name's definition includes another logical name.

job: The accounting unit equivalent to a process and its subprocesses, if any, and all subprocesses that they create. Jobs are classified as batch and interactive. For example, the job controller creates an interactive job to handle a user's requests when the user logs in to the system and it creates a batch job when the symbiont manager passes a command input file to it.

job tree: A hierarchy of all processes and subprocesses, with the main process at the top.

key: One of the following:

  1. In indexed files, a character string, a packed decimal number, a 2- or 4-byte unsigned binary number, or a 2- or 4-byte signed integer within each data record in an indexed file. The user defines the length and location within the records. OpenVMS Record Management Services (RMS) uses the key to build an index.
  2. In relative files, the relative record number of each data record in a data file. OpenVMS Record Management Services (RMS) uses the relative record numbers to identify and access data records in a relative file in random access mode.
  3. In the Sort/Merge utility, the data field in a record that contains the information by which the user wants to sort the records.

keyboard: An input device that can be operated similarly to a typewriter.

keypad: The small set of keys next to the main keyboard on a terminal.

keyword: A word reserved for use in certain specified syntax formats, usually in a command string or a statement.

lexical function: A command language construct that the DIGITAL Command Language (DCL) command interpreter evaluates and substitutes before it parses a command string. Lexical functions return information about the current process (the user identification code (UIC) or default directory, for example) and about character strings (their length or the location of substrings, for example).

line editor: A program that allows you to make additions and deletions to a file line by line.

line printer: An output device that prints files one line at a time. It is used for printing large amounts of output that would otherwise tie up a slower device. Almost every system has a device designated as the line printer. In some cases, the "line printer" is actually a high-speed terminal.

local node: The network node at which the user is physically located.

local symbol: Either of the following:

  1. A symbol meaningful only to the module that defines it. Symbols not identified to a language processor as global symbols are considered to be local symbols. A language processor resolves (matches references with definitions) local symbols. They are not known to the linker and cannot be made available to another object module. They can, however, be passed through the linker to the debugger. Contrast with global symbol.
  2. A command language symbol name that is accessible only at the current command level and subsequently invoked levels. It is deleted when the command level at which it is defined exits.

logging in: The identification of a user to the system. When users log in, they type a user name and password in response to prompts from the system. If the user name and the password match an account on the system, the user is allowed access to the system.

logging out: The process of entering the DIGITAL Command Language (DCL) command LOGOUT, which informs the operating system that the user has finished using a particular terminal.

logical device name: A character string that equates a somewhat cryptic device name to a short, meaningful name.

logical expression: An expression that has a true or false value.

logical name: A user-specified name that can be used in place of another character string to represent system objects such as files, directories, devices, and queues. Logical name assignments are maintained in logical name tables.

logical name table: A table that contains a set of logical names and their equivalence strings. A logical name can be process private or shareable. The default shareable logical name tables are job, group, system, clusterwide system, and clusterwide parent tables.

login class: User's method of logging in to the system. System managers can control system access based on the login class: local, dialup, remote, batch, or network.

login command procedure: A command procedure that is automatically executed at login and at the beginning of a batch job.

login directory: The default directory established by LOGINOUT when a user logs in.

magnetic tape: A medium on which data can be stored and accessed.

mass storage device: An input/output device on which data and other types of files are stored while they are not being used. Typical mass storage devices include disks, magnetic tapes, and floppy disks.

memory: A series of physical locations into which data or instructions can be placed in the form of binary words. Each location in memory can be addressed and its contents can be altered. Memory should not be confused with mass storage devices.

Multipurpose Internet Mail Extension (MIME): The standard used to attach nontext files to mail messages. Nontext files, such as graphics or sound files, are encoded and sent as plain text, although that text may not be readable. The recipient can decode the text into the file's original format using a MIME interpreter utility.

network: A collection of interconnected, individual computer systems.

node: One of the following:

  1. An individual computer system in a network that can communicate with other computer systems in the network.
  2. On OpenVMS VAX systems, a VAXBI interface---such as a central processing unit, controller, or memory subsystem---that occupies one of 16 logical locations on a VAXBI bus.
  3. On OpenVMS VAX systems, a VAX processor or HSC that is recognized by system communications services (SCS) software.

node specification: The first field in a file specification. This field identifies the location of a computer system in a network.

null value: A string with no characters that is represented in a command procedure by two quotation marks (" ").

numeric expression: A mathematical statement consisting of a collection of operands connected by arithmetic operators.

object: A passive repository of information to which the system controls access. Access to an object implies access to the information it contains.

open: The act of preparing a data set or file for processing.

open account: An account that does not require a password.

operand: The part of an expression that contains a value. Operands are acted on by operators during expression evaluation to produce a result.

operating system: An integrated collection of programs that controls the execution of computer programs and performs system functions.

operator: The part of an expression that tells the computer how to manipulate the operands. For example, the plus sign (+) is an operator that tells the computer to perform addition.

output file: A file that contains the results of a processing operation; for example, a file that has been sorted or edited.

parameter: Either of the following:

  1. A value passed to a command procedure equated to a symbol ranging from P1 through P8. See also command parameter.
  2. An entry in the volatile or permanent database for a network management component.

parsing: Either of the following:

  1. Breaking a command string into its elements to interpret it.
  2. Interpreting a file specification, as is done by OpenVMS Record Management Services (RMS).

password: A character string that users provide at login time to validate their identities and as a form of proof of their authorization to access their accounts. There are two kinds of passwords---system passwords and user passwords. User passwords include both primary and secondary passwords.

physical device name: A character string that uniquely identifies a physical device (such as a storage disk or a terminal) to the system.

primary password: A type of user password that is the first user password the system requests from the user. Systems may optionally require a secondary password as well. The primary password must be the password that is associated with the user name.

print form: A set of attributes that defines page set up and stock for printing.

print queue: A list of files waiting to be printed.

priority: A rank assigned to a process to determine its precedence in obtaining system resources when the process is running.

private volume: A mass storage media that has been allocated by a process for its own exclusive use.

process: The basic entity scheduled by the system software. A process provides the context in which an image executes. A process consists of an address space and both hardware and software context.

program: A series of instructions aimed at a particular result. Programming languages are a means of describing procedures so that they can be performed by a computer. See also image.

program stub: A temporary section of code that is used during the testing phase of writing command procedures. A program stub usually outputs a message stating the procedure it is replacing.

prompt: A character string appearing on a terminal screen indicating that the user must provide input.

protected object: An object containing shareable information to which the system controls access. See also object.

protection code: A series of letters that specify what access different categories of system users can have to a file or to another protected object and what they can do to it when they access it.

proxy login: A type of login that permits a user from a remote node to effectively log in to a local node as if the user owned an account on the local node. However, the user does not specify a password in the access control string. The remote user may own the account or share the account with other users.

qualifier: A portion of a command string that modifies a command verb or command parameter by selecting one of several options. A qualifier, if present, follows the command verb or parameter to which it applies and is in the format /qualifier[=option]. For example, in the command string "PRINT filename /COPIES=3," the COPIES qualifier indicates that the user wants three copies of a given file printed.

queue: Either of the following:

  1. A line of jobs to be processed; for example, a batch job queue or a printer job queue. Processing occurs primarily in first-in/first-out (FIFO) order, but does reflect the priority of the process that submitted the job. See also print queue.
  2. To add an entry in a list or table, often by using the INSQUE instruction.

random access: A method for retrieving or writing data in which the location of the data to be retrieved or written is not dependent on the location of previously retrieved or written data. Random access refers to memory or mass storage devices on which all information is equally accessible.

read: The act or capability of an image to accept data. For example, when a TYPE command is issued, the system reads the designated file from disk and writes it to the terminal. See also write.

record file address (RFA): The unique address of a record in a file. The RFA allows previously accessed records to be accessed randomly at a subsequent time. This access occurs regardless of the file organization.

Record Management Services (RMS): See RMS (Record Management Services).

record-oriented device: A device such as a terminal, line printer, or card reader. A record-oriented device's physical record is the largest unit of data that a program can access in one I/O operation.

record sorting: A sorting process in which records are kept intact and an output file consisting of complete records is produced.

relative file organization: The arrangement of records in a file in which each record occupies a cell of equal length within a bucket. Each cell is assigned a successive number, which represents its position relative to the beginning of the file.

remote node: Any node in a network, other than the node that you are currently logged in to.

restricted account: A type of OpenVMS account with a secure login procedure. The user is not allowed to use the Ctrl/Y key sequence during the system or process login command procedure. Control may be turned over to the user following execution of the login command procedures.

reverse video: A feature of a video terminal that reverses the default video contrast. If the default display is black figures on a white background, reverse video displays white figures on a black background.

RMS (Record Management Services): A set of operating system procedures that are called by programs to process files and records within files. RMS allows programs to issue GET and PUT requests at the record level (record I/O) as well as read and write blocks (block I/O). RMS is an integral part of the system software; its procedures run in executive mode.

scrolling: A feature of a video terminal that allows the display of more than one screen of text by vertical movement. For example, when the TYPE command is entered, new output appears at the bottom of the screen as the oldest output disappears off the top.

secondary password: A user password that may be required at login time immediately after the primary password has been submitted correctly. Primary and secondary passwords can be known by separate users to ensure that more than one user is present at the login. A less common use is to require a secondary password as a means of increasing the password length so that the total number of combinations of characters makes password guessing more time-consuming and difficult.

secure terminal server: OpenVMS software designed to ensure that users can log in only to terminals that are already logged out. When the user presses the Break key on a terminal, the secure terminal server (if enabled) responds by first disconnecting any logged-in process and then initiating a login. If no process is logged in at the terminal, the login can proceed immediately.

sequential access mode: The retrieval or storage of records in which a program reads or writes records one after the other in the order in which they appear, starting and ending at any arbitrary point in the file.

sequential file organization: A file organization in which records appear in the order in which they were originally written. The records can be fixed or variable length. Records can be accessed sequentially or randomly by record address. Fixed length records can also be accessed randomly by relative record number.

software: The collection of images, procedures, rules, and documentation associated with the operation of a particular computer system. For example, the operating system is software.

specification file: A command file used in the Sort/Merge utility to specify the commands and qualifiers needed to complete a sort operation.

string: A connected sequence of characters. When a text editor searches for a word or phrase in a text file, it is looking for a string. The character sequence that forms a command is often called a command string.

subdirectory: A directory file, cataloged in a higher level directory, that lists additional files belonging to the owner of the directory.

subprocess: A subsidiary process created by another process. The process that creates a subprocess is its owner. A process and its subprocesses share a pool of quotas and limits. When an owner process is removed from the system, all its subprocesses (and their subprocesses) are also removed.

subroutine: A subsidiary routine that executes when called by another program. A subroutine is often called repeatedly until a certain condition is met.

symbol: An entity that, when defined, represents a particular function or entity (for example, a command string, directory name, or file name) in a particular context.

symbol scope: The set of command procedure levels from within which the symbol can be accessed.

syntax: The particular form of a command, including the spelling and the order of qualifiers and parameters. Misspelled words are the most common syntax errors.

system manager: The person who makes resources available to users and sets up restrictions governing the use of such resources.

system password: A password required by a terminal before login can be initiated.

terminal: The general name for a peripheral device that has a keyboard and a video screen or printer. Under program control, a terminal enables users to type commands and data from the keyboard and receive messages on the video screen or printer. Examples of terminals are the LA36 DECwriter hardcopy terminal, the VT100 video display terminal, and the VT240 series video terminal.

timeout: The expiration of the time limit during which a device is to complete an I/O transfer.

time-stamp: A text string that fully specifies a data and time. For example, 11-DEC-1996 17:13:21.

UAF (user authorization file): The file that holds details of each account on the system. The UAF contains the user name, password, user identification code (UIC), quotas, limits, and privileges assigned to each account.

UFD (user file directory): A file that briefly catalogs a set of files stored on disk or tape. The UFD includes the name, type, and version number of each file in the set. It also contains a unique number that identifies that file's actual location and points to a list of its file attributes. See also directory.

UIC (user identification code): The pair of numbers assigned to users, files, global sections, command event flag clusters, and mailboxes. The UIC specifies the type of access (read, write, or read/write, and in the case of files, execute, delete, or both) available to the owner, group, world, and system.

user authorization file (UAF): See UAF (user authorization file).

user password: A password that is associated with a user. This password must be correctly supplied when the user attempts to log in so that the user is approved for access to the system. The two types of user passwords are primary and secondary; the terms also represent the sequence in which they are entered.

utility: A program that provides a set of related general-purpose functions, such as a program development utility (an editor, a linker), a file management utility (file copy or file format translation program), or an operations management utility (disk quotas, diagnostic program).

version number: The numeric component of a file specification. When a file is edited, its version number is increased by one.

video terminal: A terminal with a video screen for accepting output. See also terminal.

volume: A mass storage media such as a disk pack or reel of magnetic tape. The volume is the largest logical unit of the file structure.

volume set: The file-structured collection of data residing on one or more mass storage media.

wildcard character: A nonalphanumeric character such as an asterisk (*) or percent sign (%) that is used within, or in place of, a file name, a file type, a directory name, or a version number in a file specification to indicate "all" for the given field.

write: The act or capability of an image to send data. For example, when a PRINT command is issued, the specified file is read from wherever it is stored and is written to the printer. See also read.

Index Contents