Chapter 1 Glossary of Terms

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

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 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.

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).

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

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.

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.

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.

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.

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.

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

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.

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.

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

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.

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.

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.

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.

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.

See HP AdvanceNet.

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

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

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

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

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.

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

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

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.

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.

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

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.

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

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.

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

Storing infrequently used or out-of-date files onto tape and permanently removing them from the system disks at the same time.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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

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

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.

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.

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.

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.

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.

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

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

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

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

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

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.

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

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.

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

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.

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.

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

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

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.

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.

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

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

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

A measure of transmission speed over a communications channel.

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

A state of suspension for a process.

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

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

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.

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

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

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.

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.

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.

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

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

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

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.

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.

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.

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.

Computer industry jargon for a computer problem.

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

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

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.

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

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.

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

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

A connector between computers and peripheral devices.

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.

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.

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.

A printed circuit assembly (PCA). See board.

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.

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 determine such things as double spacing, vertical line spacing, and page ejects.

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

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

The video display part of a terminal or PC.

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

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

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

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

Input/output instructions for a channel.

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.

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

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.

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

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

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

A measurement of print density of various printers.

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

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.

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

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

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

See board.

A user-defined collection of objects.

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

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

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.

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

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

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.

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

See memory dump.

See system load tape.

See boot tape.

See UPDATE.

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.

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

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

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.

See history stack (also called command history stack).

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.

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

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

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.

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

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.

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.

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.

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.

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

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

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

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

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.

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.

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.

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.

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

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.

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

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

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

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.

See subline.

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.

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

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.

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

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

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.

See START.

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

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.

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.

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

An error detection scheme used in data communications.

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.

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

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

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.

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.

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.

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

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.

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.

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

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

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.

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

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.

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.

A task that involves entering information into a computer.

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

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

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).

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).

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

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

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

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

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

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

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

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.

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.

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

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.

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

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

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.

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

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.

See peripheral.

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.

See bus address.

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

See system configuration.

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.

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.

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

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 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.

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

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

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

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.

A set of programs that test for hardware faults.

A two-bit signal unit.

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.

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

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

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).

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.

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.

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.

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.

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

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.

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

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

A file stored on disk.

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

See mounting.

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

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.

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

The space available on a disk to store data.

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

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

See flexible disk.

A disk not recognized by the system.

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

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

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

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

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

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

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.

A terminal which can only display and transmit data.

See 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).

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

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.

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.

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

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

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

See RS 232-C.

See RS 422.

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

An organization that creates North American data communication standards.

The electric charge given by the release of integrated circuits.

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

The mechanism for indicating the end of a line.

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

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

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.

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

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.

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

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).

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.

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

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

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

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

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

See control program.

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

A procedure responsible for executing an operating system command.

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.

A statement consisting of variables, constants, and operators.

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

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).

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.

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.

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

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.

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.

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.

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.

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

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.

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.

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.

The time when a file is created.

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

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.

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 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.

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

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.

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

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

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.

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.

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

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

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.

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

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).

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

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

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

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.

A measurement of the speed of a processor.

A tape or tapes not created on an HP 3000.

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.

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

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

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.

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

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

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.

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.

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

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.

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

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

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

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.

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.

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.

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.

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.

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.

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

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.

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

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

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

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

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.

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

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.

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.

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

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.

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.

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

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.

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.

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

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.

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.

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

A graphical representation of data.

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.

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

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

Hewlett-Packard's electronic mail product.

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

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

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.

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.

A programming statement. When the IF condition is true, the THEN action is p