Chapter 1 Glossary of Terms

A

abort

A procedure that terminates a program or session if an irrecoverable error, mistake, or malfunction occurs, or if the system manager requests termination.

access

The process of obtaining data from files or acquiring the use of a device. Access implies an input/output (I/O) operation and is used as a synonym for I/O.

access codes

Access codes are assigned by the system manager to accounts and by the account manager to groups, and users. Access codes specify which users have the ability to read, write, append, lock, or execute a given file.

access control definitions (ACDs)

An ACD is how the owner of a file defines >who can do what with the file. ACDs take precedence over other access controls namely the MPE file access matrix and lockwords. The types of access are read (R), write (W), append (A), lock (L), execute (X), none (NONE), and read and copy the ACD permission file (RACD).

access method

The way in which data is moved between main storage and input/output devices.

access port (AP)

The MPE/iX system console interfaces the host system through the access port (AP) located in the channel I/O (CIO) section of the system card cage. The AP provides a user support interface for issuing hard and soft resets through software commands from the console. It allows a remote console to be enabled and to switch between console and session modes.

access rights field (ARF)

A field containing the type of memory access. It is compared with the user's privilege level to determine if the type of access the user is requesting (READ, WRITE, EXECUTE, or GATEWAY) is allowed for that page of memory.

account

A collection of users and groups. Each account has a unique name on the system. It is the method used to organize a system's users and files and track use of system resources such as central processor time, online connect time, and file space. Accounts are the principal billing entity for the use of these resources. Every user must specify an account to access the system.

account level security

The types of file access assigned by the system manager to the account when it is created. The types of access are READ, LOCK, APPEND, WRITE, and EXECUTE, abbreviated R, L, A, W, and X respectively. They may be assigned to any user (ANY), members of the account only (AC), or members of the group only (GU). The types of file access permitted are the first level of system security. The account manager may further restrict groups and users within an account by assigning them a limited set of file access modes.

account librarian capability (AL capability)

A capability assigned by the account manager to a user within the account. An account librarian can be allowed special file access to maintain specified files within the account.

account manager capability (AM capability)

A capability assigned to one user within each account who is then responsible for establishing users and groups.

account member

A person who has been granted access to the system through the use of a valid user name within an account. Account members are created by the account manager, who defines the user name and assigns the user appropriate capabilities and security restrictions.

account structure

The account structure provides organization, security, and billing for the system. It is used to allocate system resources such as central processor time, online connect time, and file space. The account is the principal billing entity for the use of system resources.

acknowledge

To answer or reply to a polling, an address, or a message.

acoustic modem

A data communications device. An acoustic modem has a cradle and form-fitting rubber cups to hold a telephone handset. The opposite of direct-connect modem.

ACTIVE state

The status of either an input or output spoolfile (defined differently for each). During input spooling, an ACTIVE file is a spoolfile being created, indicating that the input spooler is still collecting data from the input device. An ACTIVE output spoolfile is the only file being output to a device. For example, when the standard output device is the system printer the file being printed is ACTIVE.

actual file designator

The file name provided by the user. The system then uses the file name in place of the formal file designator to accomplish some task. The actual file designator is the file name listed in the directory. See formal file designator.

address

1. A number identifying an exact location in memory. A process can send data to, or retrieve data from, this address.

2. A set of values identifying a specific peripheral (I/O) device to the computer. The exact details on the formation of an address differ between systems.

address bus

The electrical conductors within a computer. They carry addresses from the CPU to components under CPU control. The 900 Series HP 3000 address bus is 32-bits wide.

advanced terminal processor (ATP)

An intelligent hardware interface between terminals and the HP 3000. The ATP handles character processing and eliminates CPU interrupts. It supports full-duplex asynchronous modems and direct memory access of user data.

AdvanceNet

See HP AdvanceNet.

algorithm

A step-by-step procedure for solving a problem in a finite amount of time.

ALLBASE/SQL

A Hewlett-Packard database management system. It provides both network and relational interfaces.

allocate

1. To locate and reserve disk space for a particular file.

2. To use the ALLOCATE command to update table entries and resolve pointers necessary for a program to execute. However, the program is not actually loaded into memory until run time.

alpha character

A character in the range of A through Z (or a-z).

alphanumeric character

A character in the range of A through Z (or a-z), or 0 through 9.

alpha test

The designation given when the reliability of a computer system is tested by internal users. For example, internal Hewlett-Packard users test and verify a new product before external customer tests are conducted.

alternate boot path

The hardware path used when booting the system from a boot tape. See boot path.

American National Standards Institute (ANSI)

A nongovernmental agency that establishes standards, including those for data processing.

American Standard Code for Information Interchange (ASCII, USASCII)

The standard method of representing character data (seven data bits plus one that is sometimes used for parity). This method was established by the American National Standards Institute (ANSI) to achieve compatibility between data devices when they are interchanging information.

analog

Data that varies continuously rather than in discrete steps. When used in reference to circuits, it means those circuits that produce an output varying as an uninterrupted function of the input. The opposite of digital.

append

To join all or part of one existing file to the end of another existing file.

application

A set of computer instructions or programs that accomplish tasks for the end user, rather than control the computer (that is what the operating system does). Examples of applications include spreadsheets, word processing programs, graphics, database management, and communications.

application layer

Layer seven of the Open Systems Interconnection (OSI) network model. Application layer tasks include the user interface to remote services.

application program

A set of computer instructions that guides the computer through a specific set of tasks (usually for the end user). Applications include spreadsheets, word processing, graphics, database management, and data communication programs.

architecture

1. The unique set of machine instructions, registers, and components, as well as the way they interact, that provides the basis of the operation of the computer's CPU.

2. In networking, a structured modular network design in which different data communications tasks are assigned to different layers or levels. See Open Systems Interconnection.

archive mode

A DBCore mode of logging that enables both rollback and rollforward recovery for HP SQL databases.

archiving

Storing infrequently used or out-of-date files onto tape and permanently removing them from the system disks at the same time.

arithmetic logic unit (ALU)

The part of a system that performs arithmetic and logic operations as part of the central processing unit (CPU). The CPU may contain one or more arithmetic logic units.

array

An ordered collection of letters, numbers, or words defined by the user. The computer stores the data in an array in continuous memory.

ASCII

American Standard Code for Information Interchange (ASCII) is the standard method of representing character data (seven bits plus one that can be used for parity). This method was established by the American National Standards Institute (ANSI) to achieve compatibility between data devices when they are exchanging information.

assembly language

A programming language in which each operation performed by the central processing unit (CPU) is written as a symbolic instruction. Assembly language is a convenient means of representing machine language (one instruction represents exactly one operation). A program known as an assembler translates instructions written in assembly language into machine language.

associated device

A device associated with a user by way of the ASSOCIATE command. Thereafter, the associated user has operator control of the designated device until the user logs off or gives up control of the device, or until the operator issues the DISASSOCIATE command.

asynchronous

A method of transmitting data serially without sending a clock signal. Each character consists of one start bit, five to eight data bits, an optional parity bit, and one or more stop bits. The opposite of synchronous.

asynchronous I/O

An I/O operation. The user process need not wait for completion before continuing execution. There are two forms, user asynchronous I/O and system asynchronous I/O.

asynchronous serial communications (ASC)

A part of the fundamental operating software package for the 900 Series HP 3000. It works in conjunction with the Datacommunications and Terminal Controller (DTC) to provide data transmission functions. The ASC software handles handshaking between the host system and its asynchronous devices, including character echoing, multiplexing, and input character buffering.

attachment unit interface (AUI)

A cable joining the local area network interface controller (LANIC) to the media attachment unit (MAU) for coaxial cable IEEE 802.3 local area network links.

attributes

Characteristics assigned to users, groups, and accounts which determine what can be done in the groups and accounts, or by the user. Attributes include file access codes and special capabilities. They enable the computer to determine what functions it will or will not allow a user, group, or account to perform.

authorization group

A security feature of HP SQL. A collection of users and groups with the same authorities within a DBEnvironment.

automatic calling unit (ACU)

A device that automatically places a telephone call after receiving instructions from the calling device.

automatic in

A computer-to-PBX connection sequence. It allows the computer to initiate an incoming connection on a specified channel from a specified device through the PBX. No telephone number is given; the device location (telephone number) is associated with the given channel by an administrative process on the PBX.

automatic master data set

A data set within a database. It contains only one data item (the key item). It is related to at least one detail data set. When a new search item value is added to a related detail set, a new entry is automatically added to the master with that item value as a key. When the last entry containing that search item is deleted from all related child data sets, the master entry is automatically deleted.

automatic out

A computer-to-PBX connection sequence. It allows the computer to initiate an outgoing connection on a specified channel to a specified device through the PBX. No telephone number is given; the device location (telephone number) is associated with the given channel by an administrative process on the PBX.

automatic restart

Main memory battery backup to automatically restart the system after a power failure. Temporary power line interruptions can be tolerated with no data loss and without needing to restart the system.

B

backplane

Wiring blocks or units that provide most of the interconnecting circuits of a system. Individual printed-circuit boards plug into the backplane. Every backplane contains multiple card cages.

backreference

The technique of using an asterisk (*) before a formal file designator to indicate that it has been previously defined with the FILE command.

backup

The process that duplicates computer data to offline media, such as magnetic tape. Backups protect data if a system problem should occur.

backup devices

System peripherals that allow you to write information to, and read information from, backup media.

battery backup unit

A box within the SPU that contains a battery to supply power to main memory during a power failure.

BASIC

Beginner's All-purpose Symbolic Instruction Code. A computer programming language.

batch processing

A method of submitting a job for processing. A job, which is submitted as a single entity, can consist of multiple commands such as program compilation and execution, file manipulation, or utility functions. Once submitted, no further interaction between the user and the job is necessary.

batch access capability (BA capability)

A default capability. It is assigned to accounts and users, allowing users to submit batch jobs.

baud

A measure of the speed at which information travels between devices. This signal speed is equal to the number of discrete conditions or signal event changes per second. When one bit represents each signal change, baud is the same as bits per second. Terminal speed settings are the most familiar references to baud rate.

beginning of tape (BOT)

A mark on a magnetic tape indicating where the tape drive will start reading or writing data.

beta test

The designation given to a product test in a limited customer environment. For example, Hewlett-Packard tests its products at selected external customer sites before they are publicly released.

binary

A method of representing numbers, alphabetic characters, and symbols in digital computers. Binary is the base two numbering system that uses only two digits, 0's and 1's, to express numeric quantities.

binary coded decimal (BCD)

A decimal notation in which individual decimal digits are each represented by a group of four bits.

binary synchronous communications (BSC)

A data link protocol, also referred to as BISYNC. A line control station in a data communications system.

bit

A binary digit; the number 0 or 1 in the base 2 numbering system (0 represents OFF, and 1 represents ON). Usually eight bits equal one byte. A bit is the smallest unit of information in a digital computer.

bit bucket

Computer jargon referring to a nonexistent computer storage area. The bit bucket is used when the system-defined $NULL file is specified in a command line as an output file. The associated write request is accepted by MPE/iX, but no physical output is actually performed.

bit-oriented protocol (bop)

A communications protocol that does not recognize a character as sequences of bits.

bit rate

The speed at which bits are transmitted. The bit rate is usually kilobits per second (Kb/s) or megabits per second (Mb/s).

bits per inch (bpi)

A measurement of data density. It expresses the number of bits recorded per inch of recording surface.

bits per second (bps)

A measure of transmission speed over a communications channel.

block

A group of one or more logical records treated as a single piece of data.

blocked

A state of suspension for a process.

blocked record

A physical record that contains more than one logical record. The opposite of unblocked record.

block mode

A terminal processing mode. It transmits groups, or blocks of characters all at once, instead of one character at a time.

board

A piece of fiberglass that holds integrated circuits (ICs or chips) and contains the connections between chips. A board is also called a card or circuit board.

Boolean

A data type with a value that is either TRUE or FALSE (binary 1 or 0).

boot

The process of loading and initializing an operating system. The term booting is derived from the phrase "pulling yourself up by your bootstraps."

boot path

Boot paths are used to bring up the system from disk or tape. The primary boot path is used for booting the system from disk resident software. The alternate boot path is used for booting the system from a boot tape. The console boot path is used to determine if the system can autoboot without operator intervention.

boot ROM

Performs tests on the computer's hardware, finds all devices that are accessible through the computer, and then loads either a specified operating system or the first operating system found according to a specific search algorithm.

boot tape

A tape created by backing up the system with the system generator (SYSGEN) utility program. The tape is then used to reload the system. Also referred to as a system load tape. Equivalent to MPE V/E coldload tape.

bottleneck

A system resource that is being completely used and is compromising system performance.

branch

A machine instruction that alters the sequence of instructions being executed by the CPU.

break

1. An operation that interrupts (suspends or aborts) an executing process and allows the user to initiate some other operation.

2. To press the Break key on the terminal or call the CAUSEBREAK intrinsic. If a process is only suspended, it may be resumed with the RESUME command.

broadcast

A communication method of sending a message to all devices on a link simultaneously.

broadcast bus network

A network in which nodes are connected by a linear run of cable. Messages are simultaneously transmitted to every node. Typically, the nodes process only those messages addressed to them and ignore all other messages. The opposite of point-to-point network.

broadcast space

An implementation to address multiple processors on a bus. Local broadcast address space is used when all processors on a bus with the I/O module are to be interrupted. A global broadcast address space is used when all processors system-wide are to be interrupted.

b-tree index

An index type supported by DBCore that maintains tuples in sorted order by key value and is used for accessing a particular tuple in a set of tuples.

buffer

The part of a computer or device memory where data is held temporarily until it can be processed or transmitted elsewhere. A buffer usually refers to a memory area that is reserved for I/O operations.

bug

Computer industry jargon for a computer problem.

bundled systems

A pricing option. It allows a group of products to be purchased at a lower cost than if they were each purchased separately.

bus

A common group of hardware lines that are used to transmit information between digitally based devices or components.

bus address

A number that is part of the address used to find a particular device. The bus address is determined by a setting on a peripheral device that allows the computer to distinguish between two devices connected to the same interface. A bus address is also referred to as a device address.

BYE

An MPE command used to terminate an interactive session on the HP 3000.

byte

A combination of eight consecutive bits treated as a unit. A byte represents one letter or number. The size of memory and disk storage is measured in bytes.

bytes per inch (BPI)

A measurement of data density; usually for tapes. It expresses the number of bytes recorded per inch of recording surface.

C

C

A high-level computer programming language that can do low-level manipulations. It allows great flexibility with type declarations.

cable

A connector between computers and peripheral devices.

cache

A small, high-speed memory buffer unit. The cache is continually updated to contain recently accessed data to reduce access time. There may be one cache or separate caches for instructions and data. HP Precision Architecture has separate caches.

cache miss

When an instruction or data required by the CPU is not stored in a cache, the procedure that occurs is called a cache miss. The required code or data is then retrieved from the main memory modules.

capability

A type of access right assigned to a subject (user, group, or account) affecting what the subject can do to an object (file, device, command) on the system.

card

A printed circuit assembly (PCA). See board.

card cage

The structure used to hold cards in their proper place inside the computer. Card cage and I/O bay are sometimes used interchangeably. However, the I/O bay usually refers to the entire cabinet containing one or more card cages used to store the cards that control I/O devices.

card image

The representation of data in the standard columns found on a punched card, which is a fixed-length record of 80 characters.

carriage-control characters (CCTL)

Carriage-control characters determine such things as double spacing, vertical line spacing, and page ejects.

catalog

A file that acts as a directory of specific objects (files, commands, messages, users, etc.) on the system.

catenet

Several networks that are joined, or concatenated, to form a network of networks. A catenet is also called an internetwork.

cathode ray tube (CRT)

The video display part of a terminal or PC.

CCITT

Comite Consultatif International Telephonique et Telegraphique (International Telegraph and Telephone Consultative Committee); an international standards group for establishing communication protocols.

central bus (CTB)

The communication path between the CPU main memory modules and the channel I/O adapters.

central processing unit (CPU)

The part of a system that interprets and executes machine instructions. The central processor contains an execution unit and a control unit. See SPU.

channel

A path within a data communications line through which data flows.

channel I/O (CIO)

Input/output instructions for a channel.

channel I/O adapter

Provides the interface between the central bus (CTB) and the channel I/O buses. Each channel I/O adapter serves as a high performance channel multiplexer. It provides a full direct memory access (DMA) for all HP-IB and LAN I/O channels and synchronizes the differing speeds and bandwidths of the CTB and channel I/O buses.

channel I/O buses (CIB)

Provides a synchronous bidirectional data path between the central bus (CTB) and I/O devices.

channel number

The number assigned to the device controller board in the I/O card cage. It is used to calculate the logical address of the device, or device reference table (DRT) number.

character

A letter, number, or symbol represented by one byte of data.

character-oriented protocol

A communications protocol that uses special control characters to relay instructions for controlling data transmission.

character set

A series of characters to substitute for a single character to name a group of files.

characters per inch (cpi)

A measurement of print density of various printers.

checksum

The combination of all binary digits in a block. The checksum is used to verify correct transmission of the block.

child process

A new process created by an existing process. The new process is thereafter known to the preexisting process as its child process. The preexisting process is called the parent process.

chip

A slice of silicon containing an integrated circuit. RAM, ROM, PROM, CPU, and EPROM are commonly used chips.

CIO adapter (CA)

The interface slot number containing the adapter for the CIO bus and central bus (CTB).

CIO expander

The channel input/output expander provides eight additional peripheral card slots to the SPU.

circuit board

See board.

circular file

1. A wraparound file structure that functions as a sequential file until it is full. As records are written to a circular file, they are appended to the tail of the file. When the file is full, the next record causes the block at the head of the file to be deleted and all other blocks to be logically shifted toward the head of the file. Circular files are useful as history files when you are more interested in information recently written to the file and less concerned about earlier material.

2. A file that can be reused (DBCore nonarchive log files are circular files).

class

A user-defined collection of objects.

class name

1. A label that is either unique to, or associated with, one or more devices in the system's I/O configuration, used to reference a particular device or class of devices. Device class names may be up to eight alphanumeric characters long, beginning with a letter. A single logical device may have multiple device class names. The HP 2680 Laser Printer, for example, is referred to as EPOC (electro-photographic output for computers), PP (page printer), or SLP (system line printer), or any other defined name. Directing output to any of these class names sends the output to a laser printer.

2. An abstract entity that can own objects in an HP SQL DBEnvironment.

clipping

To restrict plotting or drawing to a rectangular portion (window) of the total available area.

closing a file

Terminating access to a file. A file is closed by calling the FCLOSE intrinsic or terminating process execution.

cluster

A physical storage organization method supported by DBCore that can help minimize disk accesses. If a relation is clustered, the physical placement of its rows is controlled by a key value; this key is called the cluster index key.

COBOL

Common business-oriented language. A high-level computer language primarily used for business applications.

code

Code consists of the executable instructions that make up a program or subprogram.

code segment

The instructions to the CPU contained in a single logical module; one or more code segments comprise a complete program or subprogram. Code segments remain unchanged during program execution, and may be overwritten with a new code segment once the current segment has executed completely. In this way, programs larger than the maximum code segment size can execute without user intervention or a large amount of memory.

code segment table (CST)

A table that keeps track of all code segments currently being used. CST is used only in compatibility mode (CM) on MPE XL.

cold dump

See memory dump.

coldload

See system load tape.

coldload tape

See boot tape.

COLDSTART

See UPDATE.

color palette

In plotting terminology, a specific set of pen colors and line widths as defined by the pen color instructions of the graphics system being used.

column

A named collection of data in an HP SQL table or view with a particular data type and size.

command

A system-reserved word that directs the operating system, a subsystem, or a utility program to perform a specific operation.

command file

1. A set of one or more MPE/iX commands in a file that are executed by specifying the file name. See also HPPATH or UDC.

2. A set of one or more SQL or ISQL commands in a file that can be executed with the ISQL START command.

command interpreter (CI)

CI: A program that reads command lines entered at the standard input device, interprets them, determines if they are valid, and, if so, executes them.

command line history stack

See history stack (also called command history stack).

command set '80 protocol (CS/80 or CS-80)

A family of mass storage devices from Hewlett-Packard that communicate using the C/80 protocol. Examples are the HP 7911, HP 7912, HP 7914 disk/tape drives.

communication

The ability of one computer system to access or talk to other computer systems by way of telecommunication devices.

communication link

The software and hardware that moves data from the driver and card of one computer to the driver of an adjacent computer.

communications subsystem capability (CS)

Allows users to obtain exclusive access to a communications device such as a DSN/RJE line or a DSN/DS line. The capability is required to use DSN/RJE subsystems.

compatibility

The ability of software developed for one computer to work on another computer. See compatibility mode.

compatibility mode (CM)

Compatibility mode provides object code compatibility between MPE V/E-based systems and the 900 Series HP 3000. Compatibility mode allows current Hewlett-Packard customers to move applications and data to the 900 Series HP 3000 without changes or recompilation.

compile

The process of changing a program written in a source language (for example, BASIC, C, FORTRAN) into machine executable instructions. The compiled routine is then ready to be link-edited and then loaded into storage and run.

compiler

A program that translates source code written by a programmer into machine instructions. The compiler also diagnoses and reports syntax errors found in the application program.

completion list

A linked list of four-word entries made by a direct memory access (DMA) I/O card before interrupting the processor. Each DMA adapter or module (which may have more than one DMA device associated with it) has its own completion list.

complex instruction set computer (CISC)

A computer based on an architecture that uses microprogramming and complex instructions.

component name

A name identifying an object within the context of a directory object.

compound item

A named group of identically defined, adjacent items within the same data entry; an array. A compound item is subdivided into subitems.

compression

The process of translating data into a more compact form so that it can be transmitted more economically or efficiently.

computer

A device that accepts information, processes it, and supplies an output. A computer usually contains memory, a control unit, arithmetic and logical units, and a means for input and output.

concurrent directories

A decentralized system directory scheme. Each disk attached to the system contains its own directory of the files on that disk. This provides faster file access by eliminating the physical or logical serialization of a centralized directory.

configuration

1. The way in which computer and peripheral devices are programmed to interact with each other.

2. The layout of the computer system, including MPE table, memory, and buffer sizes. The configuration tells which peripheral devices are connected to the computer and how they can be accessed. The system is configured by the system supervisor, who works with the Hewlett-Packard applications engineer (AE).

connect time

The amount of time, in minutes, that a user, group, or account has used the CPU for a session or job. It is determined by executing the MPE REPORT command.

console

A terminal given unique status by the operating system. The operator uses the console to monitor and manage jobs, sessions and resources, respond to requests, and communicate with other user terminals. It is used to boot the system and receive system loader error messages, system error messages, and system status messages.

console boot path

Used to determine if the system can autoboot without operator intervention. See boot path.

console command

A command that is executable only from the system console at the = prompt (generated by pressing CTRL and the A key on the console keyboard). Console commands cannot be distributed to MPE users, since CTRL A has no meaning on a standard terminal. The logical console, however, can be moved to a standard terminal.

console logging

A system logging event. It records console commands in the system log file.

console message

A message sent to the system console by the system, an application, or a user.

constant

A fixed value (as opposed to a variable which is a symbol for a changing valuex).

continuation character

An ampersand (&) character entered as the last character of a command line. A continuation character tells the command interpreter that the command is longer than one line and is continuing onto a second or more subsequent lines.

continuation line

See subline.

control character

A member of a character set that produces action in a device rather than printing or displaying a character. In the ASCII character set, control characters are those in the range 0 through 31, and 127. Control characters are generated by pressing the CTRL key and a character key simultaneously (for example D). In documentation these two-key sequences are shown as CTRLD.

control codes

Special codes contained in data sent to a peripheral device. These codes control how the device operates.

control program

The program responsible for handling I/O for terminals and file storage, establishing processing priorities, maintaining waiting lists of work in process, activating operational programs, and performing other supervisory functions in a real-time system. Other terms used synonymously to designate such a program are driver, executive, monitor, kernel, and supervisor.

control register

A 32-bit register on the register file board, used for memory access protection, interrupt control, and processor state control.

control unit

A part of the CPU that regulates the execution unit and oversees the instruction cycle.

control-Y

A break function activated by simultaneously pressing the CTRL key and the Y key on a terminal's keyboard. It is typically a subsystem break and does not affect MPE commands. In documentation this two-key sequence is shown as CTRLY.

COOLSTART

See START.

coprocessor

A special purpose processor that works with the CPU to speed up specialized operations such as floating-point arithmetic and graphics processing.

coupled environment

The MPE/iX file system's use of the MPE V/E file system in compatibility mode to perform functions that MPE/iX does not currently handle.

CPU time

The amount of time, in seconds, that a user, group, or account has used the CPU. It is displayed by executing the MPE REPORT command.

crash

1. The unexpected shutdown of a program or system. If the operating system crashes, it is called a system crash, and the system must be rebooted.

2. A head crash or disk crash. This occurs when the read/write heads on a disk drive (that normally ride on a thin cushion of air above the disk) make physical contact with the disk surface, destroying data and the disk track. The extent of damage to the system depends on which disk crashed and how much of the disk was corrupted. A crash of the system disk is serious, since it contains the directory of user files as well as operating system programs, the I/O configuration, and the account structure.

CRC-CCITT

An error detection scheme defined by the Comite Consultatif International Telephonique et Telegraphique (CCITT).

CRC-16

An error detection scheme used in data communications.

create volumes capability (CV capability)

The ability to define and access nonsystem domain disks with the NEWSET command of VOLUTIL.PUB.SYS (use NEWVSET command for private volumes on MPE V/E). Users and accounts assigned CV capability are automatically given use volumes (UV) capability.

cursor

1. A flashing rectangle or blinking underline character on a display screen. It marks the position where text or data can be entered, changed, or deleted.

2. In HP SQL, the pointer to one tuple in a set of tuples from an application program.

customer engineer (CE)

A Hewlett-Packard field representative responsible for the installation, troubleshooting, and maintenance of computer hardware and operating systems.

custom performance consulting

Using an outside performance expert to locate and evaluate performance problems.

cyclic redundancy check (CRC)

An error detection scheme in which the checking character is generated by taking the remainder after dividing all the serialized bits in a block of data by a predetermined binary number. An equal comparison indicates no errors, while an unequal comparison indicates an error in the transmission.

cylinder

A portion of a disk pack that consists of vertically aligned tracks on each disk platter within the pack. The first track on the first platter is directly above the first track on the second platter, which is aligned with the first track on the third platter, and so on. These tracks, taken together, are considered a cylinder. Therefore, cylinder 1 refers to track 1 on each of the platters in the disk.

D

daisy wheel printer

A printer that forms characters by striking metal or plastic images of characters against a ribbon onto paper. The name comes from the shape of the print wheel, which looks like a daisy.

database (DB)

A collection of logically related data files, and structural information about the data and/or files.

database management system (DBMS)

A software package designed to protect the consistency and security of data in computer-stored files (databases). It allows a user to define a database structure and manipulate the contents by storing, retrieving, deleting, modifying, and sorting data.

data cache

A high-speed CPU cache implemented on the 900 Series HP 3000. It operates in parallel with the instruction cache. Data is transferred by load and store instructions between the general purpose registers of the execution unit and the data cache. It is a write-to cache, so the main memory modules are updated only as required. See instruction cache.

data circuit terminating equipment (DCE)

Equipment used to send information between locations, such as a modem. DCE is also known as data communications equipment.

data communications

The transmission of information from one computer or terminal to another. It is sometimes shortened to datacomm.

Datacommunications and Terminal Controller (DTC)

An MPE/iX intelligent controller, with microprocessors to handle communications with 900 Series HP 3000 systems. Each DTC may contain connection cards allowing access to X.25 networks, as well as connection cards allowing asynchronous device connections.

data communications and terminal subsystem (DTS)

The methodology used to connect all asynchronous devices to a 900 series HP 3000, except for the system console.

data dictionary

A database used as a programmer's tool to store information about data. It does not contain the data itself, but describes the type, location, usage, and relationships of the data resources of an organization.

data endpoint

The point at which the digital multiplexer interface (DMI) data channel protocol is terminated. Data endpoints can be at the host computer or at the PBX. Data endpoints are classified by the physical serial interface they would present such as terminal or communication equipment. See data circuit-terminating equipment and data terminal equipment.

data entry

A task that involves entering information into a computer.

data item

The smallest accessible data element in a database. A data item corresponds to a column in relational database terminology.

data link layer

Layer two of the Open Systems Interconnection (OSI) network model. The data link layer checks for and corrects transmission errors over the physical link.

data recovery

The process of using special utilities to recover data that cannot be used by the operating system from disks (due primarily to disk addressing problems).

data segment table (DST)

A table that identifies and provides pointer information to all data segments, including those used by MPE and user's data stacks. On the 900 Series HP 3000 the DST is used only in compatibility mode (CM).

data set

A file used in a database. There are different types of data sets: detail, manual master, and automatic master.

data switch

A dynamic port allocator. Allows access from any terminal to any system that is connected (see PBX).

data terminal equipment (DTE)

The local node or the user terminal where information enters into and exits from a data link or the computer itself.

DBCore/XL

The common services that HP SQL uses on the MPE/iX operating system.

DBEFile

The basic unit of storage used by DBCore. A DBEFile is a file on the host operating system. DBCore stores relations in DBEFileSets.

DBEFileSet

A logical grouping of DBEFiles. A relation can span DBEFiles within a DBEFileSet.

DBEnvironment (DBE)

The scope of transactions and recovery for HP SQL databases. A DBE is a collection of one or more databases.

deadlock

A condition that arises when multiple processes are waiting for resources held by other processes. A process cannot release the resources it holds until it can acquire the resources it is waiting for, but it cannot acquire these resources until another process releases them.

debug

1. To find and correct mistakes in a computer program.

2. Debug/XL is the debug facility supplied with MPE/iX. It provides debug information at the machine instruction (object code) level. It can be used to debug programs written in any Hewlett-Packard-supported language, both in native mode and compatibility mode.

decimal code

The decimal representation of an ASCII character. For example, the character A has the ASCII binary code value 01000001 and the decimal code value 65.

default

A predefined value or condition that is assumed, and used if no other value or condition is specified.

defined volume

A member volume that is not yet physically available to a volume set, but has its name, class assignments, and space allocation specified on the volume set information table (VSIT) of a system master volume. See initialized volume.

delimiter

A special character used to mark the end of a string of characters. Common delimiters are a comma (,), semicolon (;), equal sign (=), or a Return.

delta

A term used to express an incremental change. Refers to a release of the operating system with only minor changes from the previous release.

dereferencing

Dereferencing substitutes the value of a variable in place of the variable name. See explicit dereferencing and implicit dereferencing.

descriptor

A set of data structures that collectively represent the characteristics of an open file. The data structures contain the file's attributes, identification, access control, and accounting information, and are maintained by the file system routines.

destructive testing

A deliberate attempt to cause the system or program to fail by including a test specifically designed for that purpose.

detail data set

A data set in a database whose entries contain one or more search items but not a key item. Entries with the same search item value are chained together; this chain can be linked to entries in master data sets that have matching key item values. A detail data set is equivalent to a child relation that does not have a key item.

device

See peripheral.

device adapter

A device that manages communications between the computer and a peripheral device. It is the same as an I/O interface card or a printed circuit assembly.

device address

See bus address.

device class

A collection of devices. The MPE/iX file system supports a means of maintaining collections of devices.

device configuration

See system configuration.

device file

A physical device that the system treats as a file by writing to it or reading from it. Examples of device files are $STDIN and $STDLIST, the default input and output device files for the keyboard and terminal screen, respectively.

device independence

A characteristic of the operating system that allows users to selectively redirect input/output from a program, session, or job with the FILE command without regard to the nature of the device. File equations created with the FILE command are in effect only for the duration of the job or session in which they are defined.

device reference table (DRT)

A table containing the logical address of disks, tape drives, and other peripheral devices.

device subtype

A number ranging from 0 to 15, defining a specific device and its associated software driver. There can be several device subtypes within one basic type. For example, a graphics terminal and one without graphics capabilities can share the same device type, but they are assigned different subtype numbers.

device type

Device types are defined by a number. For example, 0 represents a moving-head disk and 16 is the class type number assigned to line printers.

diagnostician capability (DI capability)

A capability usually assigned only to the Hewlett-Packard customer engineer (CE). It allows the CE to conduct certain CPU and diagnostic tests.

Diagnostic Support Monitor (DSM)

The online diagnostic package for the Intelligent Network Processor (INP).

diagnostic user interface (DUI)

A means by which a user can communicate with the diagnostic system.

diagnostic utility system (DUS)

A set of utilities used to diagnose a system failure. The DUS is loaded from standalone serial storage media into the main memory of the shutdown system.

diagnostics

A set of programs that test for hardware faults.

dibit

A two-bit signal unit.

digital

A method of representing all information stored, processed, or transferred in discrete values or symbols. For example, the set of integers constitute a set of digital values. The opposite of analog.

digital multiplexed interface (DMI)

A specification for interfacing a host computer to a private branch exchange (PBX).

digitize

To convert a continuous function to one containing a finite number of discrete levels.

direct access

To read from or write to a random access device (usually a disk) by addressing a specific logical record. Direct record access is not possible on serial storage media (such as magnetic tapes) since data can only be read sequentially from the first record (or byte) to the nth record (or byte).

direct connect modem

A data communications device. A direct connect modem has a built-in phone jack, allowing the phone line to be plugged directly into the modem. The opposite of acoustic modem.

direct memory access (DMA)

A technique that allows a periperals device to gain direct access to the main memory of the computer. This method allows extremely high data transfer rates.

directory

A system table showing in what group or account each file is located, as well as its disk address, so that it can be accessed. A directory may contain other information such as size of the file, its creation date, any modification dates, file creator, or file security information.

DISCFREE

An MPE/iX utility supplying information about a system's disk free space, transient and permanent space, and the volumes total space capacity. The information is supplied in either a histogram or a condensed format. Equivalent to the MPE V/E FREE5 utility.

DISCUTIL utility

An MPE/iX utility that is used primarily to recover data from disks that cannot be used by the operating system.

disk

A circular plate, coated with material which holds a magnetic charge, used to store computer data. A disk may be fixed, removable, hard, or flexible.

disk drive

A peripheral device that reads information from and writes information to the disk.

disk failure

A disk-related problem that causes a disk to be unavailable for use.

disk file

A file stored on disk.

disk I/O

The electromechanical process of transferring the code and data that are stored on disk into main memory.

disk loaded

See mounting.

disk pack

A set of one or more disk platters stacked inside a plastic cylindrical container.

disk platter

An aluminum disk coated with magnetic material. One or more platters are mounted on a central spindle, and together they form a complete disk pack. Information may be recorded on one or both sides of each platter within the pack.

disk sector

A section of a disk's surface (256 contiguous bytes). A file is stored in one or more sectors.

disk space

The space available on a disk to store data.

disk status

The state of a disk recognized by the system. See MEMBER, MASTER, LONER, SCRATCH, and UNKNOWN.

disk swapping

The process of moving data segments from memory to disk and from disk to memory; and for moving code segments from disk to memory.

diskette

See flexible disk.

dismounted

A disk not recognized by the system.

distributed database

A database whose data is located on a number of different computers, which may be in different geographic locations.

distributed systems

Systems in which some or all of the processing functions are in different places and connected by transmission facilities.

distributed system line (DS line)

The communications line between two computers, controlled by the distributed system network.

distributed system network (DSN)

A system of hardware and software data communications products spanning multiple Hewlett-Packard product lines.

dot matrix printer

A printer in which each character is represented by a pattern of dots.

download

The process of transferring a block of information from one computer system to another.

driver

1. In hardware, driver refers to a circuit that is capable of supplying specific current and voltage requirements.

2. In software, driver refers to a program that is capable of controlling a specific input/output device. See control program.

DRT number

Device reference table number. The physical I/O address of a device controller, displayed in the second column of the I/O configuration table listed during the SYSDUMP dialog. An MPE V/E index into the DRT.

dumb terminal

A terminal which can only display and transmit data.

DUMP

1. The MPE/XL ISL DUMP utility writes system main memory and secondary storage to tape. DUMP also, optionally, attempts a software reboot from disk.

2. See cold dump.

Dump Analysis (DPAN)

See dump analysis tool (DAT)

Dump Analysis Tool (DAT)

An MPE/iX program. It produces a formatted listing of the contents of main memory after a system failure or shutdown. This aids in the analysis of fatal system events such as process hangs, system failures, or hardware failures. This tool is similar to the MPE V dump analysis program (DPAN).

duplex

The method of transmission that allows simultaneous two-way communication. Duplex is usually called full-duplex. The opposite of half-duplex.

duplicative

1. To echo input operations to a corresponding display without intervention by the operating system software.

2. The name of an MPE/iX command that writes to $STDLIST.

dynamic backup

Dynamic backup means that the STORE file set and structures are accessible for any access while the backup is taking place. Any modifications made to the STORE file set during the backup are logged and saved along with the data on the backup medium. On RESTORE, the data and log file are used to recover the data to a consistent state.

E

echo

What the computer does when it sends data typed on the keyboard back to the terminal screen. If echo is turned off, the computer receives the data, but does not send it back, so nothing appears on the screen.

echoplex

A mode in the full-duplex communication channel in which any character transmitted by a terminal is echoed back to it.

EDIT/3000

An HP 3000 text editor, supplied with MPE/iX. It is used to create and manipulate ASCII files.

editor

A word processing application used to prepare, modify, or delete text and program files. EDIT/3000 is the text editor used with MPE/iX.

EIA 232-C

See RS 232-C.

EIA 422-A

See RS 422.

electronic mail

The transmission of a message from one person to another by way of computers.

Electronics Industries Association (EIA)

An organization that creates North American data communication standards.

electrostatic discharge (ESD)

The electric charge given by the release of integrated circuits.

end of file (EOF)

The marker that indicates the logical end of a file. An end-of-file marker may be a control character embedded in the data.

end of line (EOL)

The mechanism for indicating the end of a line.

end of tape (EOT)

A marker on the back of a tape, sensed by the tape drive, indicating the supply of tape is running low.

entry

An element of information in a table, list, queue, or other organized structure of data.

environment file

A disk file containing the formatting specifications for a printed page of data. These specifications, which are not part of the data, may include the page size, character fonts, forms, and other requirements to be used in conjunction with the Hewlett-Packard Laser Printing System.

erasable programmable read-only memory chip (EPROM)

An EPROM chip can be programmed, erased, and reprogrammed.

error checking code

On an MPE/iX system, the internal memory word size is 39 bits. There are 32 bits for data and seven bits dedicated to error detection and correction. Single-bit errors are automatically detected and corrected ensuring data integrity. Multi-bit errors are automatically detected resulting in a high-priority interrupt to the system software for appropriate action.

error listing

A report generated by the system describing the step by step processing of the job.

error messages

Messages describing errors that occur during either an interactive session or a batch job. The messages are reported to the standard list device, which is usually a terminal (for a session) or a line printer (for a job).

escape key

A special terminal key that is used in combination with other characters to give those characters different functions that modify a session or terminal. The escape key is represented by ESC or Escape.

escape sequences

A sequence of characters beginning with the escape character and used to control printers, plotters, or the display screen.

EXCLUSIVE access

A restriction limiting file access to one user at a time.

execute

What the computer does when it carries out the instructions or performs the routine indicated.

executing state

The state of a job/session, displayed when the SHOWJOB command is executed. Possible states are INTRO, WAIT, EXEC*, EXEC, and SUSP.

execution unit (EU)

The part of the CPU containing the arithmetic logic unit (ALU) and the registers. Data is held in registers and manipulated in the ALU.

executive

See control program.

execution unit (EU)

The part of the CPU containing the arithmetic logic unit (ALU) and the registers. Data is held in registers and manipulated in the ALU.

executor

A procedure responsible for executing an operating system command.

explicit dereferencing

When the command interpreter encounters an exclamation point immediately before a variable name, it substitutes the value for the variable name. Explicit dereferencing may be used in any MPE/iX command. See implicit dereferencing.

expression

A statement consisting of variables, constants, and operators.

extended binary-coded decimal interchange code (EBCDIC)

An 8-bit code that is an extension of binary-coded decimal (BCD) notation. EBCDIC can represent up to 256 different characters.

extended code segment table (CSTX or XCST)

A table containing information about code segments that come from users' program files and those segments that are assigned by running a program. CSTX (or XCST) is used in MPE/iX only in compatibility mode (CM).

extended large addressing

MPE/iX can be implemented with either 48-bit or 64-bit virtual addressing. The 48-bit addressing provides a virtual address space consisting of 65,000 individual spaces each 4GB (four billion bytes) in size. This is 65,000 times larger than a typical 32-bit system.

extent

A group of one or more contiguous sectors of disk space allocated for a single file. Extents can be variable length; any number of extents can exist for a given file.

external interrupt message (EIM)

A mechanism used by a module to signal to the processor that the module has completed a requested operation and is ready for another.

extra data segment capability (DS capability)

A capability assigned by the system manager to users and accounts to use extra data segments. DS capability is normally restricted to only a few users, since allowing many processes to use extra data segments can easily overload the system, requiring large amounts of main memory, a large virtual storage area on the system disk, frequent disk swapping, or all three.

F

Facility/Link

An MPE communications subsystem. It allows users to access a mainframe computer in interactive mode using a Hewlett-Packard distributed systems network (DSN). It is usually known as Interactive Mainframe Facility/Link.

FCOPY

An HP 3000 subsystem that allows the user to copy, append, translate data from one type to another (for example, ASCII to EBCDIC), verify, and compare files. The subsystem is activated with the MPE/iX FCOPY command.

fiber optics

The technology of transmitting data over communication lines made from flexible strands of glass or plastic through which laser beams or light from light emitting diodes are passed to transfer data. The strands are formed into cables and can carry many more times the amount of data than traditional copper wire.

field replaceable unit (FRU)

An assembly that is replaced when any of its components fail.

file

A group of related records that represents ASCII text (text files) or binary data (such as executable code). Every file must have a file name so the user can access the file's contents.

file access permission

The determination whether a process may perform a requested operation on a file. Every file in the file system has a set of access permissions. These permissions are broken down according to whether a file may be read, written, or executed.

file code

A four-digit integer that identifies the special function of a file. Users may assign a file code between 0 and 1023 to a file they create to classify it according to its purpose.

file creation time

The time when a file is created.

file directory

A directory maintained by the system containing each file's name, who created it, its location, and other defining characteristics.

file equation

A method of equating a name with a specific device or file. This name serves as an "alias" for another device or file whose characteristics are defined in the file equation. The MPE/iX FILE command is used to define the file equation. File equations are often used to direct the input to or output from a program, job, or session to a particular device or file.

file identifier

A number associating a name with a file system object. For example, when you "open" a file using its name, the operating system returns a unique number for your use. This number is the file identifier.

file independence

File independence means that data files are shareable among all the Hewlett-Packard programming languages. For instance, an HP Pascal/iX program can read files created using any of the other supported programming languages.

file information display (FID)

A display of file characteristics, an error message, an error number, and current FOPEN intrinsic parameters provided when certain file input/output errors occur.

file label

A descriptive entry on disk containing the file name, file code, record size, file format, current end-of-file mark, maximum number of records, blocking factor, number of disk sectors in use, number of extents currently allocated, and maximum number of extents. Use the LISTF,2 command to display the file label.

file mark

A uniquely formatted area on a magnetic tape used to separate files. Also referred to as a tape mark.

file name

An MPE/iX file name is a string of up to eight alphanumeric characters, the first of which must be an alphabetic character.

file number

An integer value assigned by the FOPEN intrinsic that is used to refer to a file in a user program. File numbers zero through seven are reserved for the MPE/iX operating system.

file pointer

A logical record pointer kept by the operating system to indicate the next sequential record to be accessed in a file. The pointer is set to the first record when the file is opened.

file space

The number of sectors of disk space that a group, or account is using. It is displayed by executing the MPE/iX REPORT command.

file specification

The "full" name of a file. This includes the file name, group, and account.

file state

The condition of a file. This can include OPEN, READY, ACTIVE, LOCKED, or WAIT. An OPEN file, for example, is one currently being accessed by a user or a program.

file system

The part of the operating system that handles access to input/output devices, data blocking, buffering, data transfers, and deblocking.

firmware

A set of microcode instructions that are executable by the CPU. These are permanently stored in read-only memory (ROM) or writable control store (WCS).

fixed disk

A large capacity disk that is fixed inside a disk drive and cannot be removed.

fixed-length record

A record that always contains the same number of characters or words. Fixed-length records within a single file are always the same length.

fixed space font

A typeface in which each character occupies the same amount of space. The space between characters is uniform for all nonproportional fonts.

flexible disk

A random access storage device, also called a diskette or floppy disk. Data may be written to or read from one or both sides with a special disk drive intended only for diskettes. Flexible disks are often used with personal computers.

floating-point operations per second (FLOPS)

A measurement of the speed of a processor.

foreign tapes

A tape or tapes not created on an HP 3000.

formal file designator

The name that commonly appears on the left side of a file equation for the purpose of redirecting input/output to or from a file/device, or defining the characteristics of a file/device. This is the name that processes will refer to, rather than to the actual file or device.

formatting

1. Part of a process of preparing a disk for use.

2. To prepare a file to be output with a certain organization. Formatting includes such processes as setting page length and width, specifying printing fonts, and adding headers and footers.

FORTRAN

Formula translator. A high-level computer programming language often used in scientific and engineering applications.

frame

A unit of information used in packet switching. A frame contains no more than one packet.

frame checking sequence (FCS)

A 16-bit sequence derived from an algorithm common to data circuit-terminating equipment (DCE) and data terminal equipment (DTE). The sequence is appended to each frame and used as a verification of data transmission.

free space map

A map of allocated and available disk sectors on the volume set.

full-duplex

A method of transmission that allows simultaneous two-way communication. Full-duplex is also called duplex. It is the opposite of half-duplex.

fully qualified file name

A complete file description that includes the file name, the group to which the file belongs, and the account to which the group belongs. The fully qualified file name of the LETTER file in the PUB group of the SYS account is expressed as LETTER.PUB.SYS.

function keys

Special keys on the terminal keyboard that are labelled sequentially, F1, F2, F3, and correspond to the windows that appear at the bottom of the terminal screen. Function keys perform various activities.

fundamental operating software (FOS)

The programs, utilities, and subsystems supplied on the master installation tape (MIT) for MPE/iX.

G

gate

A circuit with one or more input signals to produce a single output of binary 1 or 0 depending on the type of logic built into it.

gateway

1. A special instruction used to increase the user's privilege level and perform a branch. It is required to access the operating system.

2. In data communications, a method used to access one type of network from another type. A gateway is a member of two or more networks and allows communication between the networks to which it belongs. For example, a gateway is used to go to a local area network (LAN) from X.25.

general register

A 32-bit register available to all processes at all privilege levels for general computation and data manipulation.

Glance/XL

A software product which can help in locating and evaluating performance problems. This is equivalent to the MPE/VE system measurement tools.

global

A term used to define scope. A global item is widely accessible.

global variable

A variable whose value is valid throughout a program, job, or session. Global is the opposite of local, which means that a variable is useful only in a limited area.

Governmental Agency Hardware Certification

The testing conducted for the purpose of passing governmental agency (FCC and VDE) and safety regulations (UL, CSA, IEC). Tests conducted include electromagnetic compatibility, conducted emissions, radiated emissions, and various safety tests.

group

1. A group is part of an account that is used to organize the account's files. All files must be assigned to a group, and within an account each group has a unique name. A PUB (public) group is established for each account when it is created. Additional groups are created within the account, as needed, by the account manager.

2. For the ALLBASE/SQL group, see authorization group.

group-level security

The file access modes, and the types of users to whom they are available, as specified by the account manager when the group is created.

group librarian capability (GL capability)

Assigned by the account manager, to a user within an account. A group librarian can be assigned special file access modes for the maintenance of certain files within the user's home group.

GSP

Guardian Service Processor

H

half-duplex

Communication system or equipment capable of transmission in either direction, but not in both directions simultaneously. The transmission flow must be halted each time the direction of travel is reversed. This halt is called turnaround time and typically requires from 50 to 250 milliseconds, depending upon line length. The halt is required to reverse the direction of the echo suppressers in the telephone line and to allow modems to stabilize. The opposite of full-duplex.

handshaking

A communications protocol between devices, or between a device and the CPU. The signals indicate that information was received, more is on the way, or it was not received correctly.

hard copy

The output from a printer or plotter, usually onto paper.

hard disk

A device used to store information. A hard disk has more storage than a floppy disk without being susceptible to the same hazards (for example, being bent or having the media corrupted by physical handling). A hard disk generally comes in packs consisting of several platters instead of just one. Some disk packs can be removed from the disk drive.

hard reset

A method to reset the computer or a terminal. A hard reset erases all information in memory. See soft reset.

hardware

All the physical components of the computer, including the CPU cabinet, tape drives, disk drives, terminals, and other peripherals.

hardware installation

The process of physically connecting the hardware of a computer system together.

hard-wired

In a hard-wired computer, the instruction set is implemented directly in the CPU.

hard-wired direct connection

A direct connection between a computer and a terminal or between two computers over a relatively short distance using copper wire pairs, coaxial cable, or fiber optics. The signals are transmitted in digital format.

hard-wired terminal

A terminal directly connected to the computer system by a length of cable.

head

The physical mechanism on a disk or tape drive that reads data from, and writes data to, the disk or tape. The head on a disk drive does not normally make physical contact with the surface of the media, but the tape head does.

header

The first page printed when output is directed to a line printer. It contains the session name (if designated), the session number, logon identification, day of the week, date, and time. It corresponds to the trailer printed as the last page of the output.

Help facility

An online utility providing information on all MPE commands. Information can be accessed by topic areas and tasks.

Hewlett-Packard (HP)

A Fortune 500 company founded by Bill Hewlett and Dave Packard in 1939. Hewlett-Packard is a producer of computers and headquarters is located in Palo Alto, California, U.S.A.

Hewlett-Packard Data-Link Control II (HP-DLC-II)

A Hewlett-Packard high-level data-link (HDLC) standard that defines the elements and procedures for a balanced, bit-oriented, Level II of the Open Systems Interconnection (OSI) model protocol.

Hewlett-Packard Graphics Language (HP-GL)

The graphics instruction set for Hewlett-Packard film recorders and plotters.

Hewlett-Packard Interface Bus (HP-IB)

The HP-IB channel consists of an HP-IB cable connected to an HP-IB interface card that is connected to the system's backplane. It performs protocol translation between the CPU and HP-IB. For the 900 Series HP 3000 up to six devices can be connected to a single HP-IB channel. Disk drives, tape drives, and system printers are connected by an HP-IB which is HP's implementation of the IEEE standard 488-1975 interface.

Hewlett-Packard Precision Architecture (HP-PA)

A computer architecture expressly designed for performance, extensibility, and scalability. It can be implemented on low-end and high-end computers across a complete family of computers. Precision Architecture incorporates reduced instruction set computer (RISC) technology in its architecture. Advantages include fewer components and PC boards, high reliability, and small power supplies.

Hewlett-Packard Structured Query Language (ALLBASE/SQL)

The Hewlett-Packard relational database management system (DBMS) that uses the industry standard Structured Query Language (SQL).

hexadecimal

The base 16 numbering system. The first 10 digits are 0 through 9, and the last 6 are A through F. When a number is written in base 16 it is preceded by a dollar sign ("$"). For example, $F3 is the hexadecimal representation for the decimal number 243.

hierarchical topology

A point-to-point network topology. The hierarchical topology is sometimes used with supervisory-control application, in which large databases exist at one node, possibly along with control programs that are accessed by nodes lower in the hierarchy. Hierarchical topologies are also used for distributed database applications.

High Level Data-Link Control (HDLC)

Types of protocols that eliminate much of the handshaking (and resultant time-consuming line turnarounds).

histogram

A graphical representation of data.

history stack

The history stack is a CI table that contains, by default, the 20 most recent commands entered at the system prompt during a session. The history stack is used with the REDO and DO commands. To display the commands in the history stack use the LISTREDO command.

home group

A default group, within an account, where a user logs on when no specific group is indicated.

host computer

1. A computer running a process for a user logged onto a different computer. For example, a user logs onto system A and then uses data communication software to start a session with system B and run a program. System B is the host computer.

2. In a network, the computer that primarily provides services such as computation, database access, or special programs or programming languages, to other users on the network.

HP AdvanceNet

A family of communication products, hardware and software, that allow HP systems to communicate with each other and with equipment made by other vendors.

HP Desk

Hewlett-Packard's electronic mail product.

HPSlate

An HP 3000 screen editor used to create and manipulate files.

HPSORT

An HP 3000 utility program that sorts records in a file(s) and then merges the sorted files.

HP-UX

An operating system based on AT&T Bell Laboratories' implementation of UNIX System V and containing other features. These features include Hewlett-Packard capabilities (such as graphics) and those from other UNIX systems, such as 4.2 BSD from the University of California at Berkeley. UNIX is a registered trademark of AT&T Bell Laboratories.

HPPATH

A predefined, user-modifiable MPE/iX variable that controls where the system searches for command and program files. By default these files are searched for in the user's group, followed by the .PUB group of the user's account, followed by the .PUB group of the .SYS account.

I

IF-THEN-ELSE statement

A programming statement. When the IF condition is true, the THEN action is performed. When the IF condition is false, the ELSE action is performed.

implicit dereferencing

A way of substituting the value of a variable in place of the variable name. Implicit dereferencing is used with the CALC, IF, SETVAR, and WHILE commands. See explicit dereferencing.

IMAGE

A network database management system. It consists of a set of programs and procedures used to define, create, access, and maintain a database.

implied RUN

The ability to run a program without explicitly using the RUN command. In MPE/iX it is not necessary to specify RUN EDITOR.PUB.SYS to invoke and run the EDIT/3000 program. It is only necessary to enter EDITOR.

independent files

Files that require only single-file consistency.

index

In database terminology, a list of the contents of a file, with keys or references for locating the contents. An index facilitates data retrieval.

indirect file

A text file containing the parameters for a STORE or RESTORE command that you execute regularly.

INITIAL

See system generator (SYSGEN)

initialization state

The state of a job/session when it begins to execute on its own stack. Indicated by EXEC* when the SHOWJOB command is issued.

initialize

To set to beginning values.

initialized volume

After a member volume is defined with the NEWVOL command, it can be made physically available to the volume set by giving it a volume label, label table, and free space map with the INITVOL command of VOLUTIL.PUB.SYS. See defined volumes.

initial system loader (ISL)

ISL is the software used to bring up MPE/iX or perform a memory dump to tape. It provides a user interface to obtain information about the bootpath or to alter the bootpath. It is used to boot MPE/iX or perform a memory dump to tape.

ink-jet printer

A printer that forms characters by spraying ink through a tiny jet onto paper.

input

The data to be processed, or the process of transferring data from external storage to the computer.

input/output (I/O)

The process of, or equipment used in, transmitting information to or from the computer.

input priority

A number in the range of 1 (lowest priority) to 14 (highest priority) assigned to input jobs. The input priority can be assigned by the system (default is 14) or by the user. Jobs with an input priority less than or equal to the system jobfence (default 8) are deferred.

INSTALL

The MPE/iX Initial System Loader (ISL) INSTALL utility performs a system load from tape and builds essential operating system files and data structures on disk. Equivalent to the MPE V/E RELOAD operation.

instruction cache

A high-speed cache implemented on the 900 Series HP 3000. It operates in parallel with the data cache to enhance processing efficiency. For example, data can be loaded from the data cache while the next instruction is fetched from the instruction cache. See data cache.

instruction set

The set of all possible machine instructions understood by the computer.

instruction unit

A part of the MPE/iX CPU to control instruction sequencing. It executes branch instructions, maintains processor status, and handles traps and interrupts.

integer

A data type that is either a positive or negative whole number, or zero.

integer value

A sequence of digits preceded by a plus sign (+), minus sign (-), dollar sign ($), or percent sign (%). When neither a plus sign nor minus sign is provided, a positive number is assumed. A dollar sign indicates a hexadecimal integer and a percent sign indicates an octal integer.

integrated circuit (IC)

A silicon chip on which electrical connections are etched to form electrical components. An IC may contain as many as 100,000 gates depending on the technology used. Chips are mounted on boards and connected to form processing and memory functions for a computer.

intelligent network processor (INP)

A communications input/output board used with Hewlett-Packard data communications products.

intelligent terminal

A terminal that can edit, perform error checking, and respond to programmatic instructions. An intelligent terminal may be as simple as a CRT terminal capable of block transmissions and minor editing, or as complex as a terminal that is fully user-programmable.

interactive

An interactive session allows users to enter commands and data at the terminal and receive an immediate response. Sessions are useful for data entry and retrieval, text editing, or program development where direct dialog with the computer is preferred.

interactive access capability (IA capability)

A capability assigned to accounts and users allowing users to initiate sessions with the HELLO command.

interactive mainframe facility (IMF)

An MPE communications subsystem allowing users to access a mainframe computer in interactive mode using a Hewlett-Packard distributed system network (DSN).

interactive user

A user who enters commands at a terminal.

interface

1. The connecting circuitry linking the central processor of a computer system to its peripheral devices.

2. Standards that allow systems to connect to each other (for example, RS 232-C).

interleave

A method of writing data to a disk device that improves data access speed.

International Association of Hewlett-Packard Computer Users (INTEREX)

An independent organization formed for the purpose of exchanging techniques and ideas among users of Hewlett-Packard computers.

International Standards Organization (ISO)

An organization established to promote the development of standards and to facilitate the international exchange of goods and services. ISO created the Open Systems Interconnection (OSI), a seven-layer approach to network architecture.

internetwork communication

Communication between networks. See catenet.

internetwork protocol (IP)

The network services (NS) protocol based on the Defense Advanced Research Projects Agency's (DARPA) standard. IP is primarily used to route messages between networks using gateways. It provides gateway-to-gateway routing, store-and-forward service between gateways, and message fragmentation and reassembly between source and destination networks.

interprocess communication (IPC)

An MPE file system facility that allows processes to communicate with one another.

interrupt

A signal that stops the current process and demands immediate attention (so that it gets processed).

intrinsic

A system routine accessible by user programs providing interface to operating system resources and functions. Intrinsics perform common tasks such as file access, message formatting, or data conversion.

intrinsic call

The method used to invoke, or call, an intrinsic from within a program.

I/O bay

A cabinet containing the card cages and device controller boards for peripherals connected to the HP 3000. See card cage.

I/O dependent code (IODC)

Contains I/O module dependent data, and code used by processor-dependent code (PDC) in configuring the I/O module and booting the system.

I/O error

A data transmission error between a computer and peripheral. Examples of I/O errors are baud rate or parity mismatch, and incorrect syntax in device-control instructions.

I/O interface card

See device adapter.

I/O path

The address of the interface hardware and the physical path to reach a device. It is constructed top down from where the device is physically attached to the system. The path is determined by the CIO adapter module number, the device adapter (DA) slot number, and the device address.

ISQL

The interactive interface to ALLBASE/SQL, the relational interface to ALLBASE/SQL.

J

job

A job is a method of submitting multiple operating system and utility commands for processing with a single command. Once submitted, the job executes independently of the user's session. Jobs are used to compile source programs, modify files, or perform other functions not requiring user interaction. See batch processing and stream.

job control word (JCW)

A 16-bit logical word residing in an MPE-managed table. It's used to control command execution within a job or a session. See variable or MPE/iX variable.

jobfence

A limit established to manage jobs. If a job has an input priority higher than the jobfence, it executes. If it has an input less than or equal to the jobfence, it does not execute.

job file

A file that contains commands that will be executed noninteractively. A job file begins with the JOB command and ends with the EOJ command.

job limit

A limit set to manage jobs. The system manager or operator can restrict system usage by limiting the number of jobs allowed to run on the system. If the LIMIT command is used to set the job limit to 0 (zero), no additional jobs can log onto the system.

job listing

See listing.

job number

A system assigned identification number given to each job when it is submitted for processing.

job state

A generic term for the preliminary stages, excluding initial validation, a new job or session must pass through during its lifespan. See executing states.

JSMAIN

An MPE/iX process that handles the logon dialog, maintains session tables, and creates a command interpreter (CI).

K

K

Kilo (1000). In computer terminology, K is commonly a symbol representing the number 1024, or 2 raised to the 10th power. Frequently used as a synonym for thousand.

K file

A recovery file created by EDIT/3000, with a name in the form Kdddhhmm, where the first three characters (ddd) show the Julian day, and the next four (hhmm) characters show the time in hours and minutes when work began on the file. A new K file is created every time a new file is created or an existing file is loaded for editing. If a system problem occurs, the data in the new or loaded file is saved to the K file for recovery purposes.

kernel

A set of routines in the operating system. The kernel is the executable code responsible for overall control of the computer's resources, such as allocating memory, creating processes, and scheduling programs for execution. See control program.

key

In ALLBASE/SQL, a column used in an index definition.

keyboard

A keyboard is attached to a terminal and is a means of inputting data to communicate with the system.

keyed file

A file whose records can be read in logical sequence or directly accessed by a key associated with each record.

keyed sequential access method (KSAM)

A file access method supported on the HP 3000 (and included with the fundamental operating software) in which records may be accessed either sequentially or randomly by primary or alternate record keys.

keyword

A word assigned a specific meaning by the operating system, a subsystem, computer language, or utility.

keyword parameters

Words that have special meaning to the command interpreter and are used to modify the intent or effect of an MPE/iX command. Keyword parameters, unlike positional parameters, may appear in any order after a command has been entered on the command line. An entire keyword parameter group, such as PASS=password, must be separated from other keyword parameters by a semicolon (;).

KSAM64

A new KSAM file type that has the ability to support large KSAM file sizes.

L

label table

A table that contains file labels for the files residing on the volume set.

LAN 3000/XL LINK

Provides the hardware and communications software needed to connect 900 Series HP 3000 machines to a network for system-to-system communication.

LAN cables

Cables used to connect the Datacommunications and Terminal Controller (DTC) and the system. See Thick LAN cable and Thin LAN cable.

language construct

A command grouping (for example, IF-ENDIF) used to control the flow of commands.

large file

A file whose maximum file size (the file limit) is greater than 4GB - 64KB (4,294,901,760) bytes.

laser printer

A printer that uses a laser to produce an image on a page.

laser printing

A method of printing in which a rotating drum has a raster image transferred onto it by a laser. As it rotates further, it is dusted with a fine black plastic powder called toner which adheres to the drum where it was struck by the laser. When the drum comes in contact with the paper, the toner pattern is transferred onto it and the toner is melted (fused) to make the printing permanent.

layers

The division in network architecture models. In network architecture, different transmission and communications tasks are assigned to each layer. Each layer is a logically distinct module. One example of layers is the seven-layer Open Systems Interconnection (OSI) network model developed by the International Standards Organization (ISO).

LDEV number

See logical device number.

library

A file containing a set of procedures that may be accessed by programs.

line editor

A line editor requires you to press Return to end one line of text and to begin another. EDIT/3000 is an example of a line editor.

line printer

A hardware device used for system output. A line printer prints output one line at a time.

link

To set up pointers and table entries for a compiled file and its libraries. This creates an executable file that allows a program to run.

link access protocol (LAP)

A subset of high-level data-link control (HDLC) protocol that governs the exchanges between a user and the access node of a public data network. LAP uses asynchronous response mode (ARM) of HDLC and is now used in limited applications.

link access protocol-balanced (LAP-B)

The current version of link access protocol (LAP) that uses asynchronous balanced mode (ABM) of high-level data-link control (HDLC).

link editor

See linker.

linker

A system program. It combines one or more object programs into one program, searches libraries to resolve user program references, and builds an executable file. This executable file is ready for execution through the program loader. Also referred to as link editor.

listing

A listing is the output of a job usually in the form of a printed document.

load

A machine instruction requesting the CPU to take data from memory and place it in a register.

loading

To prepare a program for execution by allocating primary memory and putting the job in a queue for execution.

local area network (LAN)

A computer network confined to a single location. For example, connecting two or more computer systems within a single office together creates a LAN.

local area network interface controller (LANIC)

A hardware card that fits into the backplane of the HP 3000 and provides a physical layer for IEEE 802.3 local area networks.

localizable

That quality of software or documentation that facilitates changes to the punctuation characters, key words, and command names to fit a particular language so that applications can be used in different countries. The user interface is in the country's native language.

local mode

A standalone method of terminal operation. A terminal is operating in local mode when it is not connected to the computer. See remote mode.

local network

The network to which the local node belongs.

local node

The node where you are physically located and logged on, and at which you enter commands.

local system console

See system console.

local variable

A variable that appears as a UDC or a command file parameter. A local variable is valid only in a certain section of code. This is the opposite of global, which has value throughout an entire program.

LOCKED state

The status of an output spoolfile when it is being accessed by the SPOOK utility, and is therefore unavailable for printing.

lockword

A word used as a security device on files. A lockword can be assigned to a file when it is created or renamed, and must be supplied to regain access to the file. The word may be from one to eight alphanumeric characters long and must begin with an alphabetic character.

log file

A file that maintains a record of events. Each event is recorded in a separate log record, and is correlated with the job or session causing the event.

logging

1. The process of recording all system modifications to a tape or disk file for the purpose of recovery or accountability. If the system fails, the log file can be used to restore the system to its state prior to the failure.

2. The process used by DBCore to record the activity of a DBEnvironment to enable either rollback or rollforward recovery if necessary.

logging shutdown

A shutdown marking the end of the logging cycle. In most cases, it is performed just prior to either system or database backup.

logic unit (LU)

1. A part of the CPU that executes arithmetic statements.

2. A program or set of programs providing access to a network for an end user.

logical device (LDEV)

The logical representation of a physical device. The representation includes a numeric identifier and a set of parameters that define the device and its address.

logical device number

An LDEV number is assigned to all hardware components of a computer system and is used for identification purposes.

logical interchange format (LIF)

A standard format for mass storage implemented on many Hewlett-Packard computers to aid in media transportability.

logical record

A collection of fields or related data, treated as a unit, residing in a file. A logical record is defined in a user program. Its length is smaller than or equal to the length of the physical record in which it resides.

log off

A method of terminating a session. To log off MPE/iX, enter the BYE or EXIT command.

log on

A method of initiating a session. To log on to MPE/iX, enter the HELLO command and a valid user and account name, plus a group name if necessary, and any required passwords.

logon group

The group accessed by defining a group name when logging on using the HELLO command. The syntax is username.accountname, groupname. Once the desired group is accessed, resident files may be referenced without fully qualifying them.

logon identity

A security device used to verify users to the system. A logon identity includes a valid user name and account name in the form user.account.

logon prompt

A system prompt (MPE/iX:) that indicates the computer is ready to initiate a session. See prompt.

logon session

The online interaction between a user and the computer. The session occurs between logging on and logging off.

logon UDC

A user-defined command (UDC) automatically executed at logon. Specified with an OPTION LOGON statement within the UDC.

LONER

A duplicate of a member volume currently online, or a volume recognized by MPE/iX as a member volume but without a master volume online. The VSCLOSE command puts all master and member volumes of a set in the LONER state.

M

machine cycle

The period of time required by a computer to perform the most fundamental operation.

machine instruction

The smallest resolvable piece of a code segment. Machine instructions are used by the CPU to accomplish a single task, such as moving an item of data to the CPU, moving it from the CPU to memory, or performing a single calculation using data in the CPU.

machine language

Binary code that is executable by the CPU. All programs must eventually be translated into machine language before they can be processed by the computer.

magnetic tape

A data storage media that comes on reels.

mainframe computer

A computer that generally has a large amount of memory and operates at high-speed, servicing multiple users and/or batch jobs.

main memory

The fast, volatile, random access storage containing all currently executing code and data segments, including portions of the operating system and any utilities in use.

maintenance word

A protection word restricting access to certain utility functions of a database. The creator can define a maintenance word for a database or a database space with HPIUtil and SQLUtil.

management information systems (MIS)

A system using equipment and certain procedures to aid the managerial decision-making process.

manual master data set

A data set in a database containing a key item and possibly other data items. A manual master does not have to be linked to a detail data set. Entries in a manual master data set must be explicitly added or deleted (compare to automatic master data set).

mapped file

The disk files that are mapped directly into the virtual address space memory, bypassing the file system and I/O routines that other disk files must use.

mapped file access

A method of transferring data to/from a disk file by implicitly using virtual pointers and primitive LOAD and STORE instructions, rather than by explicitly reading/writing using file system primitives. Mapped files are accessible by obtaining a pointer to the file that is mapped to the user's address space.

MASTER

The state of a disk recognized by the system as a master volume.

master data set

A data set with one or more data items, one of which must be a key item. A master data set is generally used as an index to one or more detail data sets. The two types of master data sets are manual and automatic.

master device

A peripheral device containing the device controller board used to control it and other slave devices.

master installation tape (MIT)

A tape containing the MPE/iX operating system, utilities, and subsystems for the HP 3000. It may be either a new version of the software, a backup of the user's system, or the original installation tape for a new site. MIT may also refer to a particular release of MPE.

master/slave

A relation between two processes in which one initiates the execution of the other, and controls all subsequent communications between them.

master volume

A master volume is the only volume needed to define a volume set. It contains the configuration data, the root directory, a free space map, file label table, and a volume label with a unique volume set ID for the volume set. See system volume.

mean time between failures (MTBF)

A statistic that predicts how often failures will occur.

mean time to recovery (MTTR)

A statistic that predicts how long a certain repair service will take.

media

Devices capable of storing data, such as disks or magnetic tapes.

medium attachment unit (MAU)

A device attached to a coaxial cable for a local area network. The MAU provides physical and electrical connection from the attachment unit interface (AUI) cable to the coaxial cable.

megabyte

A measure of memory or storage space equal to 1,048,576 bytes of characters.

member volume

A volume containing a volume label indicating it belongs to an MPE/iX volume set. It may be used by one or more volume classes.

memory

An area of the computer's circuitry that holds applications and any data generated with those applications. Information held in random access memory (RAM) is erased whenever the computer is turned off. Information held in read-only memory (ROM) is retained even when the computer is off.

memory dump

The contents of memory stored on disk or tape. A memory dump is usually used for analysis and trouble shooting.

memory error logging

A facility that records all memory errors. It begins automatically when the system is initialized.

memory-mapped I/O

A configuration in which each device or I/O interface card is assigned a set of memory locations, or memory-mapped I/O registers.

menu

A display on the terminal screen showing the options available within a program. Many application programs use menus to show the options a user can select.

message

A unit of information sent from one device or computer to another in a form that is understandable to the receiving device.

message file

A special type of file with features ideal for managing messages between processes. They also allow processes in different jobs and sessions to communicate with one another.

metadata

A data dictionary term that means data that describes other data.

microcode

Directions that define machine language instructions. Each machine instruction is a complete microprogram. Microcode directly controls how the hardware functions. Microcode runs in a fast memory called a control store.

microcomputer

A small