<comment>(edited 9-Jul-91)
<GLOSSARY>(\int_gloss)

<GTERM>(Absolute address) 
<GDEF>
The binary number that is assigned as the address of a physical memory 
storage location.

<GTERM>(Absolute section) 
<GDEF>
The portion of a program in which the programmer has specified physical 
memory locations of data items.

<GTERM>(Access time) 
<GDEF>
The interval between the instant at which data is requested from or 
for a storage device and the instant at which the data actually begins 
moving to or from the device.

<GTERM>(ADC (Analog to Digital Converter)) 
<GDEF>
A circuit that converts analog (voltage) signals to binary data.

<GTERM>(Address) 
<GDEF>
A label, name, or number that designates a location in memory where 
information is stored.

<GTERM>(Algorithm) 
<GDEF>
A prescribed set of well-defined rules or processes for the solution 
of a problem in a finite number of steps.

<GTERM>(Alphanumeric) 
<GDEF>
The subset of ASCII characters, including the 26 alphabetic characters 
and the 10 numeric characters.

<GTERM>(ANSI) 
<GDEF>
American National Standards Institute.

<GTERM>(Application program (or package)) 
<GDEF>
A program that uses the operating system to run but is not part of that 
system.  Examples include games, business management programs, and graphics 
programs.

<GTERM>(Argument) 
<GDEF>
A variable or constant value supplied with a command that controls the 
command's action, specifically its location, direction, or range.

<GTERM>(Array) 
<GDEF>
An ordered arrangement of subscripted variables.

<GTERM>(ASCII) 
<GDEF>
The American Standard Code for Information Interchange; a standard 
code consisting of 8-bit coded characters for upper- and 
lowercase letters, numbers, punctuation, and special communication 
control characters.

<GTERM>(Assembler) 
<GDEF>
A program that translates symbolic source code into machine 
instructions.  This program replaces symbolic operation codes with 
binary operation codes and symbolic addresses with absolute or 
relocatable addresses.

<GTERM>(Assembly language) 
<GDEF>
A symbolic programming language that can be translated directly into 
machine language instructions and is specific to a given type of 
central processing unit.

<GTERM>(Assembly listing) 
<GDEF>
A listing, produced by an assembler, that shows the symbolic code 
written by a programmer next to a representation of the actual machine 
instructions generated.

<GTERM>(Asynchronous) 
<GDEF>
The type of operation that is triggered by another event, as opposed 
to synchronous, or occurring at set time intervals.

<GTERM>(Background program) 
<GDEF>
A program that runs at a low priority; that is, when a higher priority 
(foreground) program is not using system resources.

<GTERM>(Backup file) 
<GDEF>
A copy of a file created as a precaution against loss of the primary 
file.

<GTERM>(Backup volume)  
<GDEF>
A volume that stores a copy of your own and/or the operating system files.
This gives you a means of replacing the files if they become 
damaged or accidentally deleted.

<Gterm>(Bad blocks)
<Gdef>
The blocks on a storage volume that are not usable because of some physical 
damage or flaw.  The INITIALIZE/BADBLOCKS command finds bad blocks and calls 
them FILE.BAD.  You can use disks or diskettes that have bad blocks, but you 
should make a backup copy and discard a volume that has many bad blocks.

<GTERM>(Base address) 
<GDEF>
An address used as the basis for computing the value of some other 
relative address; the address of the first location of a program or 
data area.

<GTERM>(BASIC--PLUS (Beginner's All-purpose Symbolic Instruction Code)) 
<GDEF>
An interactive, algebraic computer language that combines English 
words and decimal numbers.  It is a widely available, standardized, 
simple beginner's language capable of handling industry and business 
applications.

<GTERM>(Batch processing) 
<GDEF>
A processing method in which programs are run consecutively without 
operator intervention.

<GTERM>(Baud)  
<GDEF>
Also called <emphasis>(baud rate).  
The speed (in bits per 
second) at which data is transmitted over a 
data line.

<GTERM>(Binary) 
<GDEF>
The number system with a base of two; used by the internal logic of 
all digital computers.

<GTERM>(Binary code) 
<GDEF>
A code that uses two distinct characters, usually the numbers 0 and 1.

<GTERM>(Bit) 
<GDEF>
A binary digit.  The smallest unit of information in a binary system 
of notation.  It corresponds to a 1 or 0 and to a 1-digit position in 
a physical memory word.

<GTERM>(Block) 
<GDEF>

A group of physically adjacent words or bytes of a size that is 
specific to a device  (512 contiguous bytes for most disk devices).
For input/output operations, the smallest 
addressable unit on a mass storage device or the basic unit for storing 
information on a volume.
A block in
a text file contains about 80 words of text. 

<GTERM>(Boot (bootstrap))  
<GDEF>
To start an operating system on a computer.
A <emphasis>(hard) (<emphasis>(hardware)) boot is starting the operating 
system when the computer 
has been turned off. A <emphasis>(soft) 
(<emphasis>(software)) boot is bootstrapping an operating system by 
command after the computer has been turned on.

<gterm>(Boot blocks)
<gdef>
The storage area on a volume reserved for the bootstrap routine.

<GTERM>(Bootstrap) 
<GDEF>
A technique or routine whose first instructions are enough to 
start a system of programs that brings an operating system into memory.

<GTERM>(BOT (Beginning Of Tape)) 
<GDEF>
A marker that is applied near the beginning of a magtape and 
identifies the beginning of the magtape's recordable surface.

<GTERM>(Bottom address) 
<GDEF>
The lowest memory address into which a program is loaded.

<GTERM>(Breakpoint) 
<GDEF>
A location at which program operation is suspended to allow operator 
investigation.

<GTERM>(Buffer) 
<GDEF>
A storage area used to temporarily hold information being transferred 
between two devices or between a device and memory.  A buffer is often 
a special register or a designated area of memory.

<GTERM>(Bug) 
<GDEF>
A flaw in the design or implementation of a program; a problem that 
can cause erroneous results.

<GTERM>(Bus) 
<GDEF>
Interconnects computer system components to provide 
communication paths for addresses, data, and control information.

<GTERM>(Byte) 
<GDEF>
In a PDP--11 computer system, is 
the smallest memory-addressable unit of information and is equivalent to 
eight bits.

<GTERM>(Cache)  
<gdef>
A very fast small 
memory that can be used in combination with slower, large capacity 
memories. It contains copies of data recently used by the processor and 
fetches several bytes of data from memory in anticipation that the processor 
will access the next sequential series of bytes.

<GTERM>(Caching)  
<gdef>
The process 
of storing blocks in memory for future use; used to minimize the
frequency with which the disk is accessed for read operations.

<GTERM>(Call) 
<GDEF>
A transfer from one part of a program to another with the ability to 
return to the original program at the point of the call.

<GTERM>(Calling sequence) 
<GDEF>
A specified arrangement of the instructions and data necessary to pass 
parameters and control to a given subroutine.

<GTERM>(CCL (Concise Command Language))  
<gdef>
A syntax for issuing commands that lets you run a program and pass 
it a CSI command string on a single command line. 

<GTERM>(Central processing unit (CPU)) 
<GDEF>
A hardware unit of a computer that includes main memory and the 
registers and circuits that control the interpretation and execution 
of instructions. The CPU is the control center of the computer.  It performs 
all data processing, such as comparing information, calculating a value, and 
printing, displaying, or storing information.

<Gterm>(Channel)
<gdef>
A logical path connecting a user process to a physical device unit.  A user 
process requests the operating system to assign a channel to a device so the 
process can communicate with that device.

<GTERM>(Character) 
<GDEF>
A single letter, numeral, or symbol used to represent information.

<GTERM>(Character pointer) 
<GDEF>
The place where the next character typed will be entered.  During 
editing, the character pointer indicates the place in an ASCII text 
file where the next character typed will be entered into the file.

<GTERM>(Clear) 
<GDEF>
To delete the contents of a storage location by replacing the 
contents, usually with 0s or spaces.

<GTERM>(Clock) 
<GDEF>
A device in a computer system that keeps time, counts pulses, 
measures frequency, or generates regular periodic signals for 
synchronization.

<GTERM>(Code) 
<GDEF>
A system of symbols used to represent data or instructions that are 
executed by a computer.

<GTERM>(Coding) 
<GDEF>
The writing of instructions for a computer, using a system of symbols 
that is meaningful to a computer, an assembler, a compiler, or a 
language processor.

<GTERM>(Command) 
<GDEF>
A word, mnemonic, or character that, by virtue of its syntax in an 
input line, causes a computer system to perform a predefined 
operation.

<GTERM>(Command language) 
<GDEF>
The vocabulary used by a program or set of programs that directs the 
computer system to perform predefined operations.

<GTERM>(Command language interpreter) 
<GDEF>
The program that translates a predefined set of commands into 
instructions that a computer system can interpret.

<GTERM>(Command string) 
<GDEF>
A line of input entered into a computer system that generally includes 
a command, one or more file specifications, and optional qualifiers.

<GTERM>(Compile) 
<GDEF>
To produce binary code from the symbolic instructions of a high-level 
source language.

<GTERM>(Compiler) 
<GDEF>
A program that translates a high-level source language into machine 
instructions.

<gterm>(Completely Virtual Environment)
<gdef>
The program environment established when a program is loaded by VBGEXE;
typically when a program is run by the V or VRUN commands.

<GTERM>(Computer) 
<GDEF>
A machine that can be programmed to execute a set of instructions.

<GTERM>(Computer program) 
<GDEF>
A plan or routine for solving a problem on a computer.

<GTERM>(Computer system) 
<GDEF>
A data processing system that consists of hardware devices, software 
programs, and documentation that describes the operation of the 
system.

<GTERM>(Concatenation) 
<GDEF>
The joining of two or more strings of characters to produce a single 
string.

<GTERM>(Conditional assembly) 
<GDEF>
The assembly of certain parts of a symbolic program that occurs only 
when certain conditions are met during the assembly process.

<GTERM>(Configuration) 
<GDEF>
A selection of hardware devices, software routines, or programs that 
function together.

<GTERM>(Console terminal) 
<GDEF>
A keyboard terminal that acts as the primary interface between the 
computer operator and the computer system.  The console terminal is 
used to initiate and direct system operations by running software on 
the computer.

<GTERM>(Constant) 
<GDEF>
A value that remains the same throughout a distinct operation.  
(Compare with Variable.)

<GTERM>(Context switching) 
<GDEF>
The saving of key registers and other memory areas before switching 
between jobs with different modes of execution.  An example of context 
switching is the use of foreground/background programming.

<GTERM>(Conversational) 
<GDEF>
See Interactive.

<GTERM>(CPU) 
<GDEF>
See Central processing unit.

<GTERM>(Crash) 
<GDEF>
A hardware crash is the failure of a device to operate; the 
operation of an entire computer system may be affected.  A software 
crash is the result of an operating system malfunctioning; the 
system's protection mechanisms may have failed or the software may not 
have executed correctly.

<GTERM>(Create) 
<GDEF>
To open, write data to, and close a file for the first time.

<GTERM>(Cross-reference listing) 
<GDEF>
A printed listing that identifies all references in a program to each 
specific symbol in a program.  It includes a list of all the symbols 
used in a source program and the statements where the symbols are 
defined or used.

<GTERM>(CSI (Command String Interpreter))  
<gdef>
 That part of RT--11 that accepts a line of ASCII input, usually from 
the console terminal, and interprets it as a string of input specifications, 
output specifications, and options for use by a utility program.

<GTERM>(Current location counter) 
<GDEF>
A counter kept by an assembler to determine the address assigned to an 
instruction or constant being assembled.

<gterm>(Cursor)
<gdef>
A reference point on the terminal screen that shows where the next entry will 
appear.  The cursor can be a blinking block or a blinking underline character.

<GTERM>(Data) 
<GDEF>
A term used to denote facts, numbers, letters, and symbols.  Data are 
the basic elements of information that can be processed by a computer.

<GTERM>(Data base) 
<GDEF>
An organized collection of interrelated data items that allows one or 
more applications to process the items, while disregarding physical 
storage locations.

<GTERM>(Data collection) 
<GDEF>
To bring data from one or more locations to a central location for 
eventual processing.

<GTERM>(DCL (Digital Command Language))  
<gdef>
The standard interface between a user
and a Digital operating system.  Commands in this language are English-like 
words that instruct the operating system to do specific tasks.
The implementations of DCL on Digital 
operating systems are somewhat different.  The implementation of 
DCL on RT--11 is also called the KMON (keyboard monitor) 
command language.

<GTERM>(Debug) 
<GDEF>
To detect, locate, and correct coding or logic errors in a computer 
program.

<GTERM>(Default) 
<GDEF>
The value of an argument, operand, or field assumed by a program if 
not specifically supplied by the user.

<GTERM>(Default Data Device )  
<GDEF>
The device 
on which the operating system looks for files to work on or 
stores files you create when you do 
not specify a device in a command. 
This device is also  called the default storage device 
and has the logical name DK.

<GTERM>(Define) 
<GDEF>
To assign a value to a variable or constant.

<GTERM>(Delimiter) 
<GDEF>
A character that separates, terminates, or organizes elements of a  
character string, statement, or program.

<GTERM>(Device) 
<GDEF>
Any peripheral hardware connected to the processor having to do with input, 
output, or storage of information rather than the processing of information.
Devices include terminals, printers, fixed disks, and diskette drives.

<GTERM>(Device control unit) 
<GDEF>
A hardware unit that electronically supervises one or more of the same 
type of devices.  It acts as the link between the computer and the I/O 
devices.

<GTERM>(Device handler) 
<GDEF>
A system software component that lets you use devices, whether they are 
storage devices, 
terminals, printers, or whatever other devices you have connected to your 
computer.  This program 
services and controls the hardware activities of a
device connected to your CPU.

<GTERM>(Device independence) 
<GDEF>
The ability to program I/O operations independently of the device for 
which the I/O is intended.

<GTERM>(Device name) 
<GDEF>
A unique name that identifies each device unit on a system.  It 
usually consists of a two-letter device mnemonic followed by an optional 
device unit number and a colon.  For example, the common device name 
for an MSCP disk drive unit 1 is DU1:. 

<GTERM>(Device unit) 
<GDEF>
One of a set of similar peripheral devices or partitions of a device.
An example of a device unit is disk unit 0.

<GTERM>(Diagnostics) 
<GDEF>
A set of procedures used to detect and isolate malfunctions and 
mistakes.

<GTERM>(Digit) 
<GDEF>
A character used to represent one of the non-negative integers smaller 
than the radix (for example, in decimal notation, one of the 
characters 0 to 9; in octal notation, one of the characters 0 to 7; in 
binary notation, one of the characters 0 and 1).

<GTERM>(Direct access) 
<GDEF>
See Random access.

<GTERM>(Directive) 
<GDEF>
Assembler directives are mnemonics in an assembly language source 
program that are recognized by the assembler as commands to control a 
specific assembly process.

<GTERM>(Directory) 
<GDEF>
A list of files on a volume. This list is in 
a file in the form of a table containing the names of and pointers to 
files on a mass storage volume.  Directories also include creation date and 
the number of blocks for each file.

<GTERM>(Directory segment)  
<GDEF>
The basic unit, consisting of two blocks, 
in which an RT--11 directory on a disk or diskette 
is stored. You can have a maximum of
72 files for each directory segment, and 31 directory segments 
for each device unit.

<GTERM>(Directory-structured) 
<GDEF>
A storage volume is directory structured if there is a directory at the 
beginning of the volume that contains information (file name, file type, 
length, and date-of-creation) about all the files on the volume.  Such 
volumes include all initialized disks and diskettes.

<GTERM>(Disk device) 
<GDEF>
An auxiliary storage device on which information can be read or 
written.

<GTERM>(Display) 
<GDEF>
A peripheral device used to represent data graphically; normally 
refers to some type of cathode-ray tube system.

<GTERM>(Distribution volume)  
<gdef>
The 
volume (or volumes) containing the operating system files as distributed 
by Digital.  From this volume, you can create a working system volume 
geared to your requirements.

<GTERM>(Downtime) 
<GDEF>
The time interval during which a device or system is inoperative.

<gterm>(Drive Unit)
<Gdef>
The hardware that holds a volume and performs the read/write operations.

<GTERM>(Echo) 
<GDEF>
The printing of characters typed by the programmer on an I/O device, 
such as a terminal.

<GTERM>(Edit) 
<GDEF>
To arrange and/or modify the format of data; for example, to insert or 
delete characters.

<GTERM>(Editor) 
<GDEF>
A program for creating or editing text files.  KED and KEX are editors.
Editors are language independent and will edit anything in 
character representation.

<GTERM>(EEPROM (Electrically Erasable Programmable ROM)) 
<gdef>
A chip containing a SETUP table 
you can program for booting an operating system on the 
PDP--11/84 and the MicroPDP--11.

<GTERM>(Effective address) 
<GDEF>
The address used in the execution of a computer instruction.

<GTERM>(Emulator) 
<GDEF>
A hardware device that permits a program written for a specific 
computer system to be run on a different type of computer system.

<GTERM>(Entry point) 
<GDEF>
A location in a subroutine to which program control is transferred 
when the subroutine is called.

<GTERM>(EOF (End Of File))
<GDEF>
A marker (character or symbol) that indicates the end of a file. The actual
marker used depends on the media containing the file.

<GTERM>(EOT (End Of Tape)) 
<GDEF>
A warning marker applied near the end of a magtape, which indicates
the approach of the end of the magnetic recordable surface.
the end of the reel.

<GTERM>(EPROM (Erasable Programmable ROM)) 
<gdef>
A chip in the PDP--11 and the MicroPDP--11
containing CPU boot and diagnostic ROM code.

<GTERM>(Error) 
<GDEF>
Any discrepancy between a computed, observed, or measured quantity and 
the specified value or condition.

<GTERM>(Execute) 
<GDEF>
To perform an instruction or run a program on the computer.

<GTERM>(Expression) 
<GDEF>
A combination of operands and operators that can be evaluated to a 
distinct result by a computing system.

<GTERM>(Extended device unit)
<GDEF>
A device unit higher in value than 7.

<GTERM>(Extended memory)  
<gdef>
Physical memory above 28K words.

<GTERM>(Extension) 
<GDEF>
The synonym used for file type.

<GTERM>(External storage) 
<GDEF>
A storage medium other than main memory for example, a disk or tape.

<GTERM>(Factoring)  
<gdef>
A method of specifying several files at a time by 
enclosing in parentheses the part of a multiple file specification
that differs.  This part can be multiple file names, multiple sections of a 
file name, multiple file types, or multiple sections of a file type; for 
example: MEMO(1,2,30).TXT.  

<GTERM>(Field) 
<GDEF>
A specified area of a record used for a particular category of data.

<GTERM>(FIFO (First In/First Out)) 
<GDEF>
A data manipulation method in which the first item stored is the first 
item processed.

<GTERM>(File) 
<GDEF>
Information stored on a volume is organized into units called files.
A file can contain, for example, a memo, a single program, or a 
collection of data.

<GTERM>(File maintenance) 
<GDEF>
The activity of keeping a mass storage volume and its directory up to 
date by adding, changing, or deleting files.

<GTERM>(File name) 
<GDEF>
The alphanumeric character string assigned by a user to identify a 
file.  It can be read by both an operating system and a user.  A file 
name has a fixed maximum length that is system dependent.  (The 
maximum length in an RT--11 operating system is six characters, the 
first of which must be alphanumeric.  Spaces are not allowed.)

<GTERM>(File specification (filespec))
<GDEF>
A name that uniquely identifies a file maintained in any operating 
system.  A file specification generally consists of at least three 
components:  a device name, a file name, and a file type.

<GTERM>(File-structured device) 
<GDEF>
A device on which data is organized into files.  The device usually 
contains a directory of the files stored on the volume.  For example, 
a disk is a file-structured device, but a printer or terminal is not.

<GTERM>(File type) 
<GDEF>
An alphanumeric character string field assigned to a file either by RT--11
or the user, which can be read by both. 
System-recognizable file types are used to 
identify files having the same format. If present in a file 
specification, the file type follows the file name in a file 
specification, separated from the file name by a period. The
maximum length is three characters.

<GTERM>(Flag) 
<GDEF>
A variable or register used to record the status of a program or 
device; the detection of errors by a translating program.

<GTERM>(Floating point) 
<GDEF>
A number system in which the position of the radix point is indicated 
by the exponent part of a number and another part represents the 
significant digits or fractional portion of a number (for example, 
5.39 x 10(8) -- Decimal; 137.3 x 8(4) -- Octal; 101.10 x 2(13) -- Binary.)

<GTERM>(Flowchart) 
<GDEF>
A graphical representation for the definition, analysis, or solution 
of a problem, in which symbols are used to represent operations, data, 
flow, and equipment.

<GTERM>(Foreground) 
<GDEF>
The area in memory designated for use by a high-priority program.  The 
program that gains the use of machine facilities immediately on 
request.

<GTERM>(Format)  
<gdef>
In 
RT--11, the FORMAT utility formats a disk or diskette by writing headers on 
each block in that volume.  The header of a block contains data the device 
controller uses to transfer information to and from that block.

<GTERM>(FORTRAN (FORmula TRANslation)) 
<GDEF>
A language designed to permit scientists, engineers, and others 
to express mathematical operations in a form with which they 
are familiar.  It is used in a variety of applications, including 
process control, real-time data acquisition, information retrieval, and 
commercial data processing.

<GTERM>(FSM (File Structured  Module))  
<gdef>
A 
set of macro routines that implement a file structure for magtape handlers
(MT, MM, MS, and MU).  FSM routines perform functions (such as read and write) 
relating to file structures on magtapes.

<GTERM>(Full duplex) 
<GDEF>
In communication, pertaining to a simultaneous, 2-way, independent, 
asynchronous transmission.

<GTERM>(Function) 
<GDEF>
An algorithm, accessible by name and contained in the system software, 
that performs commonly used operations.  For example, the square root 
calculation function.

<GTERM>(General register) 
<GDEF>
One of eight 16-bit internal registers in the PDP--11 computer.  These 
are used for temporary storage of data.

<GTERM>(Global) 
<GDEF>
A value defined in one program module and used in others.  Globals are 
often referred to as entry points in the module in which they are 
defined and as externals in the other modules that use them.

<GTERM>(Half duplex) 
<GDEF>
Pertaining to a communication system in which 2-way communication is 
possible, but only one way at a time.

<GTERM>(Handler) 
<GDEF>
See Device handler.

<GTERM>(Hardware) 
<GDEF>
The physical equipment components of a computer system.  The computer, 
terminal, drive units, and printer are all hardware.

<GTERM>(Hardware bootstrap) 
<GDEF>
A bootstrap that is stored in the hardware and need only be 
activated by specifying the appropriate load and start address.

<GTERM>(High-level language) 
<GDEF>
A programming language whose statements are translated into more than 
one machine language instruction.  Examples are BASIC--PLUS and FORTRAN--77.


<GTERM>(High memory)  
<gdef>
See Extended memory.

<GTERM>(High-order byte) 
<GDEF>
The most significant byte in a word.  The high-order byte occupies bit 
positions 8 through 15 of a PDP--11 word and is always an odd address.

<GTERM>(Image mode) 
<GDEF>
A mode of data transfer in which each byte of data is transferred 
without any interpretation or data changes.

<GTERM>(Indirect address) 
<GDEF>
An address that specifies a storage location containing either a 
direct (effective) address or another indirect (pointer) address.

<GTERM>(Indirect command file) 
<GDEF>
A file containing commands that are processed sequentially. 

<GTERM>(Indirect control file)
<GDEF>
A file that can be read and processed by the indirect control (IND)
processor. Commands are not necessarily processed sequentially.
<GTERM>(Initialize) 
<GDEF>
To set counters, switches, or addresses to starting values at 
prescribed points in the execution of a program, particularly in 
preparation for reexecution of a sequence of code.  To format a 
volume in a file-structured format in preparation for use 
by an operating system.

<GTERM>(Input) 
<GDEF>
The data to be processed; the process of transferring data from 
external storage to internal storage.


<GTERM>(Instruction) 
<GDEF>
A coded command that tells the computer what to do and where to find 
the values it is to work with.  A symbolic instruction looks like 
ordinary language.  Symbolic instructions must be changed into machine 
instructions before they can be executed by the computer.

<GTERM>(Interactive processing) 
<GDEF>
A technique of user/system communication in which the operating system 
immediately acknowledges and acts upon requests entered by the user at 
a terminal.  Compare with batch processing.

<GTERM>(Interface) 
<GDEF>
A shared boundary.  An interface might be a hardware component to link 
two devices, or it might be a portion of storage or registers 
accessed by two or more computer programs.

<GTERM>(Internal storage) 
<GDEF>
The storage facilities that form an integral physical part of the 
computer and that are directly controlled by the computer; for 
example, the registers of the machine and main memory.

<GTERM>(Interpreter) 
<GDEF>
A computer program that translates and executes a source language 
statement before translating and executing the next statement.

<GTERM>(Interrupt) 
<GDEF>
A signal that, when activated, causes a transfer of control to a
specific location in memory and breaks the normal flow of control of 
the routine being executed.

<GTERM>(Interrupt-driven) 
<GDEF>
Software that uses the interrupt facility of a computer to handle I/O 
and responds to user requests. RT--11 is such a system.

<GTERM>(Interrupt vector) 
<GDEF>
Two words containing the address of an interrupt service routine and 
the processor state at which that routine is to execute.

<GTERM>(I/O (Input/Output)  device) 
<GDEF>
A device attached to a computer that can bring 
information into the computer or get information out.

<GTERM>(Iteration) 
<GDEF>
Repetition of a group of instructions.

<GTERM>(Job) 
<GDEF>
A group of data and control statements that does a unit of work.  A 
program and all of its related subroutines, data, and control 
statements; also, a batch control file.

<GTERM>(KMON (Keyboard MONitor)) 
<gdef>
The part 
of the monitor that interprets the command 
language you use to communicate with the computer. See also DCL.

<GTERM>(Label) 
<GDEF>
One or more characters used to identify a source language statement or 
line.

<GTERM>(Latency) 
<GDEF>
The time from the initiation of a transfer operation to the beginning 
of actual transfer; that is, verification plus search time.  The delay 
while waiting for a rotating memory to reach a given location.

<GTERM>(Library) 
<GDEF>
A file containing one or more macro definitions or one or more 
relocatable object modules, which are routines that can be incorporated 
into other programs.

<GTERM>(LIFO (Last In/First Out)) 
<GDEF>
A data manipulation method in which the last item stored is the first 
item processed; a push-down stack.


<GTERM>(Linkage) 
<GDEF>
The code that connects two separately coded routines and passes values 
and/or control between them.

<GTERM>(Linked file) 
<GDEF>
A file whose blocks are joined by references rather than by 
consecutive locations.

<GTERM>(Linker) 
<GDEF>
A program that combines many relocatable object modules into an 
executable module.  It satisfies global references and combines 
program sections.

<GTERM>(Listing) 
<GDEF>
The printed copy generated by a printer or hard-copy terminal.

<GTERM>(Load) 
<GDEF>
To store a program or data in memory.  To place a volume on a device 
unit and put the unit on line.

<GTERM>(Load map) 
<GDEF>
A table, produced by a linker, that provides information about a load 
module's characteristics; for example, the transfer address, the 
global symbol values, and the low and high limits of the relocatable 
code.

<GTERM>(Load module) 
<GDEF>
A program in a format that is ready for loading and executing.

<GTERM>(Location) 
<GDEF>
An address in storage or memory where a unit of data or an instruction 
can be stored.

<GTERM>(Locked) 
<GDEF>
Pertaining to routines in memory that presently cannot be swapped or 
transferred.

<GTERM>(Logical device name) 
<GDEF>
An alphanumeric name assigned by the user to represent a physical 
device.  The name can then be used synonymously with the physical 
device name in all references to the device.  Logical device names are 
used in device-independent systems to enable a program to refer to a 
logical device name assigned to a physical device at run-time.
By default, RT--11 uses two logical device names: SY and 
DK.  SY represents the device from which the operating system is
booted, and DK 
represents the device on which RT--11 stores files by default or looks for 
files on which to operate.  You create a logical device name when issuing the 
ASSIGN or MOUNT command.

<GTERM>(Loop) 
<GDEF>
A sequence of instructions that is executed repeatedly until a 
terminal condition prevails.

<GTERM>(Low memory)  
<gdef>
Physical memory between 0 and 28K words.

<GTERM>(Low-order byte) 
<GDEF>
The least significant byte in a word.  The low-order byte occupies bit 
positions 0 through 7 in a PDP--11 word and is always an even address.

<GTERM>(Machine language) 
<GDEF>
The language used by the computer when performing operations.

<GTERM>(Macro) 
<GDEF>
An instruction in a source language that is equivalent to a specified 
sequence of assembler instructions, or a command in a command language 
that is equivalent to a specified sequence of commands.

<GTERM>(Main program) 
<GDEF>
The module of a program that contains the instructions at which 
program execution begins.  The main program usually exercises primary 
control over the operations performed; it also calls subroutines or 
subprograms to perform specific functions.

<GTERM>(Mask) 
<GDEF>
A combination of bits that is used to manipulate selected portions of 
any word, character, byte, or register while retaining other parts for 
use.

<GTERM>(Mass storage) 
<GDEF>
Pertaining to a device that can store large amounts of data that are 
readily accessible to the computer.

<Gterm>(Main Memory)
<Gdef>
A series of storage locations within the computer where the computer processes 
your data.

<GTERM>(Matrix) 
<GDEF>
A rectangular array of elements.  Any matrix can be considered an 
array.

<GTERM>(Memory) 
<GDEF>
Any form of data storage, including main memory and mass storage, in 
which data can be read and written.  Memory usually refers to main 
memory.

<GTERM>(Memory image) 
<GDEF>
A replication of the contents of a portion of memory, usually in a 
file.

<GTERM>(Mnemonic) 
<GDEF>
An alphabetic easy-to-remember representation of a function or machine 
instruction.

<GTERM>(Monitor) 
<GDEF>
The master control program that observes, supervises, controls, or 
verifies the operation of a computer system.  The collection of 
routines that controls the operation of user and system programs, 
schedules operations, allocates resources, performs I/O, and so forth.

<GTERM>(Monitor command) 
<GDEF>
An instruction or command issued directly to a monitor.

<GTERM>(Monitor command mode) 
<GDEF>
The state of the operating system --- indicated by a period at the 
left margin --- that allows monitor commands to be entered from the 
terminal.

<GTERM>(Mount a volume) 
<GDEF>
To logically associate a physical mass storage medium with a physical 
device unit.  To place a volume on a physical device unit; for 
example, to place a magtape on a magtape drive and put the drive on 
line.

<GTERM>(MSCP (Mass Storage Control Protocal)) 
<gdef>
A Digital control protocol for disk devices.  Devices controlled by
this protocol are called 
MSCP devices.

<GTERM>(Multiprocessing) 
<GDEF>
Simultaneous execution of two or more computer programs by a computer 
which contains more than one central processor.

<GTERM>(Multiprogramming) 
<GDEF>
A processing method in which more than one task is in an executable 
state at any one time, even with one CPU.

<GTERM>(Nondirectory-structured) 
<GDEF>
Refers to a storage volume that is sequential in structure and 
therefore has no volume directory at its beginning.  File information 
(file name, file type, length, and date-of-creation) is provided with 
each file on the volume.  Such volumes include magtape and cassette.

<GTERM>(Non-file-structured device) 
<GDEF>
A device, such as a printer or terminal, in which data cannot be 
organized as multiple files.

<GTERM>(Object code) 
<GDEF>
Relocatable machine language code.

<GTERM>(Object module) 
<GDEF>
The primary output of an assembler or compiler, which can be linked 
with other object modules and loaded into memory as a runnable 
program.  The object module is composed of the relocatable machine 
language code, relocation information, and the corresponding global 
symbol table defining the use of symbols within the module.

<GTERM>(Object Time System (OTS)) 
<GDEF>
The collection of modules that is called by compiled code to 
perform utility or supervisory operations; for example, 
FORTRAN IV Object Time System.

<GTERM>(Octal) 
<GDEF>
Pertaining to the number system with a radix of eight; for example, 
octal 100 is decimal 64.

<GTERM>(ODT) 
<GDEF>
The On-line Debugging Technique:  an interactive program for finding and 
correcting errors in programs.

<GTERM>(Off-line) 
<GDEF>
Pertaining to equipment or devices not currently under direct control 
of the computer.

<GTERM>(Offset) 
<GDEF>
The difference between a base location and the location of an element 
related to the base location.  The number of locations relative to the 
base of an array, string, or block.

<GTERM>(One's complement) 
<GDEF>
A number formed by interchanging the bit polarities in a binary 
number; for example, 1s become 0s; 0s become 1s.

<GTERM>(On-line) 
<GDEF>
Pertaining to equipment or devices directly connected to and under 
control of the computer.

<GTERM>(Op-code (operation code)) 
<GDEF>
The part of a machine language instruction that identifies the 
operation the CPU is to perform.

<GTERM>(Operand) 
<GDEF>
The data upon which an instruction operates. An operand is usually 
identified by an address part of an instruction.

<GTERM>(Operating system) 
<GDEF>
The collection of programs, including a monitor and system programs, 
that organizes a central processor and peripheral devices into a 
working unit for the development and execution of application 
programs.

<GTERM>(Operation) 
<GDEF>
The act specified by a single computer instruction.  A program step 
undertaken or executed by a computer; for example, addition, 
multiplication, and comparison.  The operation is usually specified by the 
operator part of an instruction.

<GTERM>(Operation code) 
<GDEF>
See Op-code.

<GTERM>(Operator's console) 
<GDEF>
The set of switches and display lights used by an operator or a 
programmer to determine the status of the computer system and to start 
the computer.

<GTERM>(Option) 
<GDEF>
An element of a command or command string that enables the user to 
select alternatives associated with the command.  In the RT--11 
operating system, an option consists of a slash character (/) followed 
by the option name and, optionally, a colon and an option value.

<GTERM>(Output) 
<GDEF>
The result of a process; the transferring of data from internal 
storage to external storage.

<GTERM>(Overflow) 
<GDEF>
A condition that occurs when a mathematical operation yields a result 
whose magnitude is larger than the hardware is capable of handling.

<GTERM>(Overlay segment) 
<GDEF>
A section of code treated as a unit that can overlay code already in 
memory and be overlaid by other overlay segments when called from the 
root segment or another resident overlay segment.

<GTERM>(Overlay structure) 
<GDEF>
A program overlay system consisting of a root segment and optionally 
one or more overlay segments.

<GTERM>(Page) 
<GDEF>
That portion of a text file delimited by form feed characters and 
generally 50 to 60 lines long.  Corresponds approximately to a 
physical page of a program listing.

<GTERM>(Parameter) 
<GDEF>
A variable that is given a constant value for a specific purpose or 
process.

<GTERM>(Parity) 
<GDEF>
A binary digit appended to an array of binary digits to make the sum 
of all bits always odd or always even.  It is used to check the 
validity of data.

<GTERM>(Patch) 
<GDEF>
To modify a routine in a rough or expedient way, usually by modifying 
the binary code rather than by assembling it again.

<GTERM>(PC) 
<GDEF>
See Program counter.

<GTERM>(PDP) 
<GDEF>
A Programmable Data Processor.

<GTERM>(Peripheral device) 
<GDEF>
Any device distinct from the computer that can provide input and/or 
accept output from the computer.

<GTERM>(Physical device) 
<GDEF>
An I/O or peripheral storage device connected to or associated with a 
computer.

<GTERM>(Physical device name)  
<gdef>
A 2- or 
1-letter mnemnonic, a unit number, and a colon (for example DU1:) by
which the operating system identifies a device handler that enables you to 
interact with a device.

<GTERM>(Priority) 
<GDEF>
A number, associated with a task, that determines the order in which 
the monitor will process the request for service by that task, 
relative to other tasks requesting service.

<GTERM>(Process) 
<GDEF>
A set of related procedures and data that are executed and manipulated 
by a computer.


<GTERM>(Processor status word (PSW)) 
<GDEF>
A register in the PDP--11 that indicates the current priority of the 
CPU, the condition of the previous operation, and other basic 
control items.

<GTERM>(Program) 
<GDEF>
A set of machine instructions or symbolic statements that 
performs a task.

<GTERM>(Program counter (PC)) 
<GDEF>
A register used by the central processor unit to record the addresses 
of the instructions to be executed.  The PC (register 7 of the eight 
general registers) always contains the address of the next 
instruction to be executed, or the second or third word of the current 
instruction.

<GTERM>(Program development) 
<GDEF>
The process of writing, entering, translating, and debugging source 
programs.

<GTERM>(Programmed request) 
<GDEF>
A set of instructions (available only to programs) that is used to 
invoke a monitor service.

<GTERM>(Program section) 
<GDEF>
A named, contiguous unit of code (instructions or data) that is 
considered as an entity and that can be relocated separately without 
destroying the logic of the program.

<gterm>(Prompt)
<Gdef>
Text displayed that requests information from the user.  Also, 
a symbol displayed 
by the operating system or a program indicating the computer is ready to 
receive commands.  The RT--11 monitor prompt is a period (.).

<GTERM>(Protocol) 
<GDEF>
A formal set of conventions governing the format and relative timing 
of information exchange between two communicating processes.

<GTERM>(Pseudo device handler)  
<gdef>
A piece of code that looks like a device handler to the monitor but is 
not one; for example, the Symbolic Debugger.  A pseudo device handler is 
similar to a device handler in that it can
accept such monitor commands as INSTALL, LOAD, and SHOW.  It 
is dissimilar to a device handler in that it does not handle devices and does 
not do any I/O.

<GTERM>(PSW) 
<GDEF>
See Processor status word.

<GTERM>(Queue) 
<GDEF>
Any dynamic list of items; for example, items waiting to be scheduled 
or processed according to system- or user-assigned priorities.

<GTERM>(Radix) 
<GDEF>
The base of a number system; the number of digit symbols required by a 
number system.

<GTERM>(Radix-50)  
<gdef>
An octal 
numbering system that represents 50 octal (40 decimal) characters.
Radix-50 uses 
a character-packing algorithm that permits the storage of 3 characters in
a 16-bit word (rather than 2, which the standard octal code allows).  Radix-50
is used in various ways, such as 
to store file names in RT--11 directories.

<GTERM>(RAM (Random-Access Memory)) 
<GDEF>
Memory that is accessed so that the next location from 
which data is to be obtained is not dependent on the location of the 
previously obtained data.

<GTERM>(Random access) 
<GDEF>
Access to data in which the next location from which data is to be 
obtained is not dependent on the location of the previously obtained 
data.  Contrast Sequential access.

<GTERM>(Read-only memory (ROM)) 
<GDEF>
Memory whose contents are not alterable by computer instructions.

<GTERM>(Real-time processing) 
<GDEF>
The computation performed while a related or controlled physical 
activity is occurring.  The results of the computation can be used for 
guiding the process.

<GTERM>(Record) 
<GDEF>
A collection of related items of data treated as a unit; for example, 
a line of source code or a person's name, rank, and serial number.

<GTERM>(Reentrant) 
<GDEF>
Pertaining to a program composed of a shareable segment of pure code 
and a nonshareable segment that is the data area.


<GTERM>(Register)  
<gdef>
A temporary storage 
location in the hardware logic section of the CPU (rather than in
main memory).  Registers are divided into three types: general, 
processor, and device registers. See also General register.

<GTERM>(Relative address) 
<GDEF>
The number that specifies the difference between the actual address 
and a base address.

<GTERM>(Relocate) 
<GDEF>
In programming, to move a routine from one portion of storage to 
another and to adjust the necessary address references so that the 
routine, in its new location, can be executed.

<GTERM>(Resident) 
<GDEF>
Pertaining to data or instructions that are permanently located in 
main memory.

<GTERM>(Resource) 
<GDEF>
Any means available to users, such as computational power, programs, 
data files, storage capacity, or a combination of these.

<GTERM>(Restart) 
<GDEF>
To resume execution of a program.

<GTERM>(RMON (Resident MONitor))
<gdef>
The part of the monitor 
that provides the console terminal service and central 
program code necessary for both system and user programs.  It always remains 
in computer memory, regardless of system operations, and is the basic source 
of control in the computer.

<GTERM>(ROM) 
<GDEF>
See Read-only memory.

<GTERM>(Root segment) 
<GDEF>
The segment of an overlay structure that, when loaded, remains 
resident in memory during the execution of a program.

<GTERM>(Routine) 
<GDEF>
A set of instructions arranged in proper sequence to cause a computer 
to perform a desired operation.

<GTERM>(Run) 
<GDEF>
A single, continuous execution of a program.

<gterm>(Run-group commands)
<gdef>
Those commands that can run a background job: RUN, R, VRUN, and V.

<Gterm>(Scroll)
<GDEF>
A feature of moving upward or downward the lines of information displayed
on a terminal screen.

<GTERM>(Sector) 
<GDEF>
A physical portion of a disk mass storage device.

<GTERM>(Segment) 
<GDEF>
See Overlay segment.

<GTERM>(Sequential access) 
<GDEF>
A method of data access in which the next location from which data is 
to be obtained immediately follows the location of the previously 
obtained data.  Contrast Random access.

<GTERM>(Software) 
<GDEF>
The programs that control a computer. Software can be
divided into five main categories: monitors, device handlers, utilities, 
language processors, and application programs.

<GTERM>(Software bootstrap) 
<GDEF>
A bootstrap that is activated by loading the instructions of the 
bootstrap and specifying the appropriate load and start address.

<GTERM>(Source code) 
<GDEF>
Text, usually in the form of an ASCII format file, that represents a 
program.  Such a file can be processed by an appropriate system 
program.

<GTERM>(Source language) 
<GDEF>
The system of symbols and syntax used to describe a procedure that a 
computer can execute.

<GTERM>(Spooling) 
<GDEF>
The technique by which I/O with slow devices is placed on mass storage 
devices to await processing.

<gterm>(Startup Command File)
<gdef>
An indirect command file that is automatically processed when you start 
RT--11.  The startup files STRTSB.COM, STRTFB.COM, STRTXM.COM, and 
STRTZM.COM are provided to run under the SB, 
FB, XM, and ZM monitors respectively. 

<GTERM>(Storage) 
<GDEF>
Pertaining to a device into which data can be entered, in which it can 
be held, and from which it can be retrieved at a later time.

<GTERM>(String) 
<GDEF>
A connected sequence of entities, such as a line of characters.

<GTERM>(Subprogram) 
<GDEF>
A program or a sequence of instructions that can be called to perform 
the same task (though perhaps on different data) at different points 
in a program, or in different programs.

<GTERM>(Subroutine) 
<GDEF>
See Subprogram.

<GTERM>(Subscript) 
<GDEF>
A numeric valued expression or expression element that is appended to 
a variable name to uniquely identify specific elements of an array.  
Subscripts are enclosed in parentheses.  There is a subscript for each 
dimension of an array.  Multiple subscripts must be separated by 
commas.  For example, a 2-dimensional subscript might be (2,5).

<GTERM>(Supervisory programs) 
<GDEF>
Computer programs that have the primary function of scheduling, 
allocating, and controlling system resources.

<GTERM>(Swapping) 
<GDEF>
The process of moving data from memory to a mass storage device, 
temporarily using the empty memory area for another purpose, and then 
restoring the original data to memory.

<GTERM>(Synchronous) 
<GDEF>
Pertaining to related events where all changes occur simultaneously or 
in definite timed intervals.

<GTERM>(Syntax) 
<GDEF>
The structure of expressions in a language and the rules governing the 
structure of a language.

<GTERM>(System program) 
<GDEF>
A program that performs system-level functions.  A program that is 
part of the basic operating system (for example, a system utility 
program) is a system program.

<gterm>(System support handler)
<gdef>
A form of pseudohandler used by RT--11 to make certain necessary connections
with a particular processor's hardware. Examples include PI for the CTI 
Bus-based processors and UB for UNIBUS processors that support UNIBUS Mapping
Registers. System support handlers are loaded into memory before the
system device handler.

<GTERM>(System volume) 
<GDEF>
The volume on which the operating system is stored.

<GTERM>(Table) 
<GDEF>
A collection of data in a well-defined list.

<GTERM>(Terminal) 
<GDEF>

An I/O device that includes a keyboard and video screen (or other
display mechanism).  In PDP--11 systems, a terminal is used as the 
primary communication device between a computer system and a user.

<GTERM>(Time sharing) 
<GDEF>
A method of allocating resources to multiple users so that the 
computer processes a number of programs concurrently.

<GTERM>(TMSCP (Tape Mass Storage Control Protocol))
<gdef>
A Digital control protocol for tapes that is similar to MSCP, the Digital 
control protocol for devices.

<GTERM>(Toggle) 
<GDEF>
To use switches on the computer operator's console to enter data into 
the computer memory.

<GTERM>(Translate) 
<GDEF>
To convert from one language to another.

<GTERM>(Trap) 
<GDEF>
A conditional jump to a known memory location performed automatically 
by hardware as a side effect of executing a processor instruction.  
The address location from which the jump occurs is recorded.  It is 
distinguished from an interrupt, which is caused by an external event.

<GTERM>(Truncation) 
<GDEF>
The reduction of precision by ignoring one or more of the least 
significant digits; for example, 3.141597 truncated to four decimal 
digits is 3.141.

<GTERM>(Turnkey) 
<GDEF>
Pertaining to a computer system sold in a ready-to-use state.

<GTERM>(Two's complement) 
<GDEF>
A number used to represent the negative of a given value in many 
computers.  This number is formed from the given binary value by 
changing all 1s to 0s and all 0s to 1s and then adding 1.

<GTERM>(UCF (User Command First))  
<GDEF>
An RT--11 feature that lets you write your own keyboard monitor 
processing utility to intercept a command line before KMON attempts DCL, CCL, 
or UCL parsing.

<GTERM>(UCL (User Command Linkage))  
<GDEF>(An RT--11 feature that lets you define your own commands.)

<GTERM>(Underflow) 
<GDEF>
A condition that occurs when a mathematical operation yields a result 
whose magnitude is smaller than the smallest amount the hardware can 
handle.

<GTERM>(UNIBUS mapping register (UMR))
<GDEF>
A set of hardware registers in certain PDP--11 processors that 
direct memory access between an 18-bit bus and 22-bit memory.

<GTERM>(User program) 
<GDEF>
An application program.

<GTERM>(USR (User Service Routines)) 
<GDEF>(The 
part of the monitor that enables you to 
access information 
stored on disks and tapes.)

<GTERM>(Utility program) 
<GDEF>
Any general-purpose program included in an operating system to perform 
common functions.

<GTERM>(Variable) 
<GDEF>
The symbolic representation of a logical storage location that can 
contain a value that changes during a processing operation.

<GTERM>(Vector) 
<GDEF>
A consecutive list of associated data.

<GTERM>(Volume) 
<GDEF>
A mass storage medium that can be used for file-structured data 
storage.

<GTERM>(Wildcard) 
<GDEF>
A valid substitute for characters in a file specification.  Used to 
perform operations on multiple files.  Can be asterisks to represent 
entire file names or file types, or percent signs to represent single 
characters in file names or file types.

<GTERM>(Wildcard operation) 
<GDEF>
A shorthand method of referring to all files with a specific 
characteristic in their name.

<GTERM>(Word) 
<GDEF>
Sixteen binary digits treated as a unit in PDP--11 computer memory.

<GTERM>(Working system volume)  
<GDEF>(The 
volume containing the operating system files adapted to your needs.)

<GTERM>(Write-enabled) 
<GDEF>
The condition of a volume that allows information to be written on it.

<GTERM>(Write-protected) 
<GDEF>
The condition of a volume that protects the volume against information 
being written on it.

<ENDGLOSSARY>