OS-9

Glossary

OS-9 Glossary


active processes. Operations that the system is currently executing.
 active state. An operating or working condition. A procedure in an active
 state is processing data and not waiting for another procedure to end.
 address. A number that identifies a location in your computer's memory.
 age. A count of the number of switches (process changes) the system has
 made since a process's last time slice.
 anonymous directory. A directory referenced by its hierarchical position
 using the period (.) character. One period refers to the current directory.
 Two periods refer to the parent of the current directory, and so on.
 application program. A process or group of processes designed to
 accomplish specific tasks, such as word processing, data management,
 game playing, and so on.
 argument. Data you supply to a process or command for it to evaluate.
 array. Data arranged so that each item is located by its row and column
 position. Single-dimensioned arrays have one or more rows and one
 column. Multi-dimensioned arrays have one or more rows and two or more
 columns.
 ASCII code. American Standard Code for Information Interchange. A
 method of defiining alphabetic and numeric characters and other symbols
 by giving each a unique value. For instance, the ASCII value for A is 65,
 and the ASCII value for B is 66.
 assembler. A program that produces machine code from source code
 (code from a low-level computer language).
 assembly language. A system for coding computer instructions to perform
 tasks. You can use assembly language code to directly manipulate data
 within a computer; therefore, assembly language needs less interpretation
 than higher level languages like BASIC or Pascal. attribute. See file
 attribute.
OS-9 Glossary
background processing. Executing one or more procedures
 and at the same time continuing to operate in OS-9 or in
 another procedure.

 backup. An identical copy of the contents of one disk on
 another disk.

 base. The lowest value allowed in a function or operation. For
 instance, BASIC09 allows a base value of 1 for array structures
 unless you indicate otherwise.
 batch file. See procedure file.

 baud. Bits-per-second. A unit for measuring the speed of data
 flow between devices.

 binary. A numbering system using only two digits, 0 and 1. In
 this system, shifting the position of a digit to the left raises the
 value of the digit by the power of 2. For instance, 1 is the binary
 equivalent of 1, 10 = 2, 100 = 4, 1000 = 16, and so on.

 bit. The smallest unit of a computer's memory. Eight bits form
 a byte. Each bit can have a value of either 0 or 1.

 bit map. A storage area of 256 bytes. Each bit represents one
 page (256 bytes) of your computer's memory. If a bit is set
 (equals 1) then its associated memory page is allocated. If a bit
 is reset (equals 0) then its associated memory page is free.
 block. A group of data, often comprising 256 bytes.

 block-oriented device. A device that receives data, sends
 data, or both, in groups of 256 bytes.

 Boolean logic. A binary type of algebra developed by George
 Boole.

 Boolean data type. A type of variable that can have only two
 values, True or False. Boolean data types usually store the
 results of comparisons, such as: is A greater than B (A>B), does
 Y equal X (Y = X), and so on.
 boot. The process of loading and initializing OS-9.

 bootfile. A disk file containing the necessary information and
 instructions to load and execute the OS-9 system.

 bootlist. A disk file containing a list of modules to be loaded
 during an OS-9 boot.

 1-2

bootstrap module. A program that contains the code neces
 sary to initialize OS-9.

 border. An area around a screen or window that defines the
 boundaries of the screen or window.

 branch. To leave one routine and begin execution of another
 routine within a program or procedure.

 breakpoints. Locations in a program or procedure at which
 you want execution to pause.

 buffer. A temporary storage area through which OS-9 trans
 fers data.

 byte. A unit of computer memory storage that contains a value
 in the range 0-255.

 byte data type. A numeric type of variable that can contain
 unsigned eight-bit integer data (in the range 0-255 decimal).

 call. (1) To transfer execution to another routine, then return
 to the calling procedure with obtained values intact and avail
 able for use by the calling routine. (2) A built-in OS-9 routine
 that performs a system function.
 CC3Disk. The floppy diskette driver module.
 CC310. The system input/output driver.

 chaining. A process of calling and turning over system control
 to a new procedure.

 checksum. A value calculated from the contents of a file or
 module that the system can later use to verify whether the con
 tents of the file or module are uncorrupted.

 child or child process. A process begun from another (par
 ent) process.
 close. The process of deallocating the path to a device or file.

 cluster. A group of sectors. In OS-9 for the Color Computer, a
 cluster consists of only one sector.

 code. Numeric data that can be used by a computer to perform
 a task.
 command. The name of an OS-9 program or function.
OS-9 Glossary
command line. One or more commands with all their parame
 ters, options, and modifiers.

 command modifiers. Data or values appended to a command
 that change the way the command functions.

 command options. Data that you can include in a command
 line to specify the way the command functions.

 command parameters. Data or values appended to a com
 mand that define or customize the command.

 command separator. A semicolon. You can use a semicolon to
 separate several commands on the same command line.

 compile. To create machine language code (object code) from a
 program written with a computer language. Also to translate
 high level code (from a high level language such as BASIC) into
 low level code (code that is like machine language).

 complement. A value that is derived by subtracting a number
 from a constant. For example, the 10s complement of 4 is 6. In
 binary, a value is complemented by changing all the 1 digits to 0
 and all the 0 digits to 1, then adding 1 to the least significant'~
 (rightmost) digit.

 complex data structure. A group of data that contains two or
 more types of data structures. See data structure.

 constant. A value or block of data that is fixed (does not
 change during the run of a program or procedure).

 CPU. Central Processing Unit. An integrated circuit (chip)
 that controls the operation of a computer.

 current directory. The directory in which OS-9 looks for data
 files or stores data files unless you specify otherwise.

 current line. When editing, the line on which the editing cur
 sor or pointer is located.

 cursor (text). A colored box that shows where the next charac
 ter is to appear on the screen. A text cursor appears on both text
 and graphics windows or screens. --

 cyclic redundancy check (CRC). A value the system calcu
 lates from the data stored in a module. The system calculates a
 new value each time it attempts to load the module. If the new
 value and the old CRC are not the same, the system cannot load
 the module.

 1-4
                          OS-9 Glossary


cylinder. A disk track that includes both sides of a disk. See
 also track.

 DAT. Dynamic address translation. The memory management
 system used by OS-9 Level Two.

 data directory. The directory in which OS-9 automatically
 saves files unless you specify otherwise.
 data structure. A unit of data, organized for access.

 data type. A method for representing data, such as character
 (ASCII value), integer (whole number), or real (floating point
 number).
 deadlock. See deadly embrace.

 deadly embrace. A situation in which two processes attempt
 to gain control of the same disk areas at the same time.
 debug. To find and correct program errors.

 decompile. To translate machine language code into a com
 puter language code.

 delimiter. A character that divides items. For instance, in
 OS-9, the semicolon is a delimiter that divides two commands on
 the same line.
 descriptor. See device descriptors.

 device. A data source, destination, or both. OS-9 devices can
 exist in your computer's memory (such as a window or a RAM
 disk), or they can be external equipment (such as a printer or
 disk drive).

 device descriptors. Small tables that define a device, its
 name, its driver, and its file manager. Device descriptors also
 contain port initialization data and port address information.

 device drivers. Modules that handle basic input/output func
 tions for specific devices. Each device you use with your computer
 must have its own driver to interpret the code you send it.

 device name. A unique system word for a device. The name for
 disk Drive 0 is /D0, the name for Window 1 is /W1, and so on.
 device table. See device descriptor.

                                  1-5

OS-9 Glossary
device window. An OS-9 device from which you can run a
 program or utility. Access device windows in the same manner
 as you do other devices. Each device window has its own input .-.
 and output buffers. Refer to windows using device names (/W fol
 lowed by a number), such as /Wl, /W2, /W3, and so on.

 directory. A file in which OS-9 stores a list of other files,
 including their names, locations on the disk, attributes, and so
 on.

 disk allocation map. Logical Sector Number 1 on a disk. The
 data in LSN1 indicates which sectors are allocated to files and
 which sectors are free.

 double click. To press and release the mouse button twice in
 quick succession when the pointer is over the desired location.

 drag. To hold down the mouse button and move the mouse to a
 new position before releasing the button.

 draw pointer. An indicator that determines where the next
 graphics draw command will begin unless you specify otherwise.

 driver. See device driver. '"

 dump. To write the contents of a video screen, a memory loca
 tion or a file to another terminal, memory location, or file.

 echo. To cause data being sent to one device to go to another
 device, as well.

 edit. To change the data or values in a file or in your comput
 er's memory.

 edit buffer. An alternate workspace for the OS-9 Macro
 Editor.

 edit macro. A series of commands you can execute with only a
 single command.

 edit pointer. An indicator that determines where the next edit
 command is to operate unless you specify otherwise.

 editor. A program that provides special commands to aid you
 in changing the contents of a file.

 error code. A code that OS-9 displays when it cannot under
 stand what you want it to do or when your computer or a periph
 eral malfunctions. Use the displayed code number to look up a
 description of the error.

 1-6
                          OS-9 Glossary


error path. The route through which OS-9 sends error codes
 and other information to display on the screen. The error path is
 designated as Path Number 2.

 error trap. A routine in a procedure that checks for an error
 and provides an alternate action (other than terminating execu
 tion and displaying a system error message).

 executable file. A program file that you can run by typing
 and entering its filename.

 execute. To start a procedure, program, or command (cause it
 to run).

 execution directory. The disk directory that contains your
 system's command fiIes.
 execution modifiers. See command modifiers.

 execution offset. The location in a program or subroutine at
 which execution begins, calculated from the beginning of the
 module.

 expressions. Data items joined by arithmetic operators. See
 also operator.

 expression stack. A memory location in which BASIC09
 stores temporary results while it evaluates an expression.

 file. (1) A block of information your computer uses for a partic
 ular function or program. A file can contain an operating sys
 tem, a language, an application program, or text. (2) A collection
 of associated records, such as information about each book in a
 library.

 file attribute. Data that identifiles a file, for instance its size,
 security status, language type, and so on.

 file locking. Protecting a file to ensure that one process does
 not change it while another process is using it.

 file pointer. An indicator that determines where in a file the
 next read or write operation is to occur unless you or the system
 indicates otherwise.

 file security. A set of attributes that determines who can use
 a file and in what manner.

 filename. A set of characters that uniquely identifies and
 locates a block of data stored on a disk.

                                1-7

OS-9 Glossary
filter. To alter data in some manner as it passes between two
 devices or between two memory locations.

 flag. A symbol or value that indicates when a certain condition
 exists in a procedure.

 font. A character set. A group of alphabetic and numeric char
 acters and other symbols of a particular style and shape.

 foreground. (1) An OS-9 task that takes priority over other
 concurrently running tasks. (2) Characters or designs on a
 screen or window.

 fork. The process of initializing one procedure from another
 procedure.

 format. To magnetically organize a diskette so that the com
 puter can use it to store data.

 function. In BASIC09, an operation that BASIC performs on
 data. A function always returns (produces) a value of some type.

 Get/Put buffer. A buffer in which you or the system can store
 fonts, screen patterns, graphic displays, overlay windows, and
 other recallable data. The system allocates Get/Put buffers in 8
 kilobyte blocks.

 getstat. An OS-9 routine that gets (returns) the state or status
 of a specific system operation.

 global variable. A variable that is available to all procedures
 and routines in a program.

 graphics. An arrangement of elements (lines, dots, and so on)
 on your computer's screen.

 graphics cursor. An indicator (either visible or invisible) that
 determines where the next graphic function is to occur on the
 screen unless you or a program specifies otherwise. In applica
 tions, you often move the graphics cursor using a mouse.
 graphics pointer. See graphics cursor.

 graphics screen. A screen in which all pixels are represented
 by bits in a memory map. You create images on the screen by
 manipulating the bits using special OS-9 or computer language
 commands.

 1-8
                          OS-9 Glossary


graphics window. A window created on a graphics screen.
 You can display both graphics (drawn images) and text on a
 graphics window. The text generated on a graphics window/
 screen uses software fonts that you or the system must load into
 memory.

 group. An organization of related data or files. For instance,
 OS-9's graphics buffers are organized into groups that you refer
 ence by number.

 hardware. The physical parts of your computer, including its
 disk drives, keyboard, integrated circuits (chips), and so on.

 header. Data located at the beginning of a file or module to
 identify its type, size, verification values, and so on.

 hexadecimal. A number system to a base of 16 (using 16 dig
 its). Hexadecimal digits are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C,-~D,
 E, and F. Shifting a hexadecimal digit one place to the left
 causes its value to be multiplied by 16.

 high order bit. The most significant or leftmost bit in a byte.
 If the high order bit is 0, it represents a value of 0. If the high
 order bit is 1, it represents a value of 128.
 I/O. Input/Output.

 identification sector. Logical Sector Number 0 on a disk.
 LSNO contains a description of the physical and logical organiza
 tion of a disk.

 immortal shell. An OS-9 shell that does not die on receiving
 an EOF signal (such as when you press CTRL BREAK ).

 integer data type. A type of variable that can store whole
 numbers in the range -32768 to 32767.

 interactive window. A window that is getting input from the
 keyboard. This window is currently on the displayed screen.

 interface. To link devices or modules together in order to
 transfer data.

 internal integrity check. A system of internal values that
 OS-9 can use to make certain that its system modules and func
 tions are accurate.

 IOMAN. The input/output manager that provides common pro
 cessing for all input/output operations.

                                1-9

OS-9 Glossary
IRQ. Interrupt request. A signal that causes the execution of
 one process to halt and the execution of another process to begin.
 The system retains the values of the first process so that it can
 later continue its execution.

 kernel. OS-9 software that supervises the OS-9 system and
 provides basic system services, such as multitasking and memory
 management, and that links all system modules.

 key sequence. Two or more keys you press at the same time to
 produce a specific function.

 keyboard mouse. An OS-9 function that lets you use the key
 board arrow keys instead of an external mouse device. Press
 CTRL CLEAR to toggle the keyboard mouse on and off.
 keyword. A command name.
 kill. Terminate the execution of a process.
 kilobyte. 1024 bytes.
 link. To make a module available to a process.
 link count. The number of processes using a module. When a '`
 module's link count reaches 0, OS-9 deallocates the module.

 load. To transfer data from an external device into your com
 puter's memory.
 local variable. A variable that can be used by only the proce
 dure or routine in which it resides.
 locked. See file locking.
 lockout. See file locking.

 log in. To initiate the necessary procedure to operate OS-9
 from a separate terminal (type in a user name and password).

 logical address. An offset address. An address that is num
 bered from the beginning of a block rather than from the begin
 ning of memory, a module, or other storage area.

 logical sectors. Sectors that OS-9 or a program references in
 numeric order, regardless of their actual physical location on a
 disk.

 loop. A sequence of BASIC09 commands that execute repeat
 edly a specified number of times or until a specific condition
 occurs to terminate the execution.

 1-10
                          OS-9 Glossary


macro. A series of commands you can execute with only a sin
 gle command name.
 map. See memory map.

 mask. A pattern of bits that you use in combination with a
 logical operator to change specified data selectively - reversing
 certain bits without affecting the others.
 megabyte. One million bytes.

 memory. The portion of your computer that stores data and
 values.

 memory management. Assigning and mapping memory to
 keep track of modules (processes and data) and their uses.

 memory map. A chart depicting the use of your computer's
 memory by the operating system.

 menu. A screen display from which you select an action for
 your computer.

 microprocessor. An integrated circuit (chip) that controls the
 basic operation of your computer.
 mode. A particular function of a program or system.

 modem. Modulator/demodulator. A device to prepare signals
 for transmission through telephone lines and to reverse the pro
 cess after transmission.
 modifier. See command modifier.

 module. An OS-9 program or block of data residing in your
 computer's memory.

 module body. A module's code (program or data), including
 the module name.

 module directory. A table in your computer's memory that
 lists all the modules residing in memory.

 module header. Code that resides at the beginning of all mod
 ules and that contains information about the module, including
 size, type, attributes, storage requirements, and its execution
 starting address.
 monitor. The video display device connected to your computer.

                                1-11

OS-9 Glossary
mouse. A device you use to control a pointer on the display
 screen. In application programs, you can often use a mouse to
 indicate functions you want to initiate.

 multi-programming. A method of computer operation in
 which the system allocates slices of execution time to more than
 one process in order to execute them concurrently.

 multi-tasking. Executing more than one process at the same
 time.

 multi-user. A system that lets more than one person access its
 functions at the same time.

 nesting. Incorporating one structure into another structure of
 the same type. Both procedures then retain their individual
 identities.

 non-shareable file. A file or module that can be used by only
 one procedure or user at one time.

 null string. A string variable that does not contain a value
 (has a length of 0 characters).
 object code. Machine language instructions.

 offset. The difference between a location and a beginning loca
 tion. For instance, you can tell some BASIC09 graphics functions
 to begin operation at a location that is offset from the current
 draw pointer position.

 operand. A value that is used or manipulated during an oper
 ation or during the execution of an instruction.

 operating system. A set of associated programs that carry
 out your commands.

 operator. A symbol or word that signifies some action to be
 performed on specified data.
 options. See command options.

 output path. The route through which the system sends data
 from one device to another.

 overflow. A condition in which a storage space is not large
 enough to contain the data sent to it.

 overlay. A condition in which programs or modules in a com
 puter's memory are replaced with other data.

 1-12
                          OS-9 Glossary


overlay window. A window opened or placed on top of a device
 window.
 overwrite. To replace data with other data.

 owner. An entity that has control over a file, module, or
 process.
 pack. To compile a BASIC09 procedure. See compile.
 padding. Adding spaces to a string or unit of data to make it
 a specific length.
 page. In your computer's memory, a block of 256 bytes.
 paint. To fill all or a portion of the screen with a color.

 palette. A register that contains a numeric code representing a
 color or shade.
 parameters. See command parameters.

 parent or parent process. A process that forks (starts)
 another process (a child process).

 parity. A system in which all binary numbers of a code are
 converted to either even-bit numbers (an even number of is and
 Os) or odd-bit numbers (an odd number of is and Os).
 parse. To search through a list or sequence of data.
 Pascal. A high-level computer language.

 pass by value. When BASIC09 passes a value from one proce
 dure to another by evaluating a constant or expression and plac
 ing the result in temporary storage to be accessed by the second
 procedure.

 pass by reference. When BASIC09 passes a variable from one
 procedure to another by providing the second procedure with the
 address of the variable's storage.

 passive window. Any window that is not receiving input from
 the keyboard. A process can be running on a passive window
 provided that the process is getting its input from a source other
 than the keyboard.

                                1-13

OS-9 Glossary
pathlist. The route from one position in a disk's directory to
 another directory or file.
 pel. See pixel.

 peripherals. Devices connected to your computer, such as
 printers, disk drives, and so on.

 permission. The attributes of a file or module that determine
 who can use the file or module and in what manner.

 physical sectors. The actual arrangement of sectors on a
 disk's surface, regardless of any internal organization by OS-9.

 pipe. A function in which the output of one process becomes
 the input of another process.

 pipeline. A series of commands, each of which passes the
 results of its operations to the next command in the series.

 PIPEMAN. The pipe file manager. Pipes are memory buffers
 acting as fiIes to transfer data between processes.

 pixel. The smallest area of a display screen that can be manip
 ulated (turned off or on).

 pointer. An indicator that determines a location in memory, in
 a file, or on the screen.

 port. A junction between devices through which data flows. An
 electrical connection between your computer and a peripheral.
 position independent module. A module that need not be
 loaded at any certain location in memory.
 procedure. A program or routine your computer can execute.

 procedure file. A file containing one or more OS-9 commands.
 You can execute a procedure file in the same manner as you exe
 cute OS-9 commands or programs.

 process. A computer program or a routine that performs a
 specific task as part of a computer program.

 process descriptor. A block of data that includes information
 about a process, its state, memory allocations, priority, queue
 pointers, and so on.

 process ID. A unique number the system gives each process it
 executes.

 1-14
                          OS-9 Glossary


process priority. A value you or the system gives to a process
 that determines the amount of CPU (execution) time it is to
 receive in a multi-tasking environment.

 process state. The condition of a process in regard to its exe
 cution. A process can be active (executing), waiting (awaiting its
 turn for processing), or sleeping (inactive until it receives a sig
 nal to awaken).

 program. Code that causes your computer to perform some
 function or a series of functions.

 program modules. Executable code. Modules you can run to
 perform a function or series of functions.

 public. Any user of a program or module other than the owner.
 See owner.

 purge. Delete. Usually refers to removing all, or a selected
 group, of files from a directory.

 RAM. Random access memory. Computer memory you can
 write to (change) and read from.

 RAM disk. A portion of your computer's memory that OS-9
 can use for data storage and retrieval in the same manner as it
 uses an external disk drive. However, be certain you copy RAM
 disk data to a floppy diskette or hard disk before you exit OS-9
 or turn off your computer. If you do not, the data is lost.

 random access. Reading (accessing) information in a block of
 data without first having to read any preceding data.

 raw data. Unformatted information that is passed to a device
 exactly as it exists.

 RBF. The random block file manager that processes all disk
 input/output.

 re-entrant programs. Programs or modules that can be used
 by more than one process at the same time.

 read. The process of transferring data from a device into the
 computer's memory.

 read permission. System permission to read (withdraw data
 from) a file.

                                1-15

OS-9 Glossary
read data type. A type of variable that can store floating
 point numbers in the range ± 1 x 10=38.

 record. A collection of related data items that a program or
 process considers to be a unit for the purpose of processing. A
 subdivision of a file, such as all information about a single item
 in an inventory file.

 record locking. Protecting a portion of a file to ensure that
 one process does not change it while another process is using it.

 recursive procedure or routine. A procedure or routine that
 repeatedly executes itself (that contains a statement causing it
 to run itself one or more times).

 register. A location within a computer's memory (often in the
 CPU) for storing values during arithmetic, logic, or transfer
 operations.

 remarks. Text contained in a program that describes the pro
 gram itself and that is not to be executed.

 ROM. Read only memory. Computer memory containing con
 stant values that the computer can read but cannot change.
 ROOT directory. The parent directory of all files and directo
 ries on a disk. The ROOT directory is created by FORMAT.
 run. To execute, or to cause a program or procedure to start.
 runtime. The duration of a program's execution.

 SCF. The sequential character file manager that handles non
 disk input/output operations to devices such as printers and
 terminals.

 scratched. Destroyed. When you copy one file over another file,
 or the contents of one disk onto another disk, any data existing
 in the second file or on the second disk is scratched.

 sector. A division of a disk track. Disk tracks are organized
 into several sectors.

 seek. To position a file pointer at a specific byte location in a
 file.

 semigraphics. Graphics (designs on the display screen) using
 ASCII graphic characters.

 1-16
                          OS-9 Glossary


sequential access. The process of reading data in order, one
 character at a time.

 sequential execution. Executing a series of commands or pro
 cesses, one after the other.

 sequential file. A file consisting of records of various lengths
 that must be accessed one after the other, starting at the first
 record.

 serial. Refers to transmissions in which data leaves or arrives
 at a location or device, with data units following one after the
 other in space or time.

 Setstat. An OS-9 routine that sets (changes) the state or sta
 tus of a specific system operation.
 shell. The command interpreter.

 sibling. One of two or more processes executed by the same
 parent process.

 sign bit. The leftmost bit of a binary number that serves as an
 indicator to show whether the number is positive or negative.
 Normally, a value of 0 indicates positive, and a 1 indicates
 negative.

 signal. An interrupt from the system or another process that
 changes a procedure's or a device's state. For example, signals
 set an active process to a waiting state, awaken an inactive or
 sleeping process, or change the display window.

 single step. A procedure in the Debug mode that lets you exe
 cute one procedure statement and (optionally) view the results.

 single-user file. A file that only one person can access at a
 time.

 single-user module. A program that only one person can use
 at a time.

 sleeping state. A situation where you or the system suspends
 a process for a specified time or until you or the system sends it
 a wakeup signal.

 source code. Program code produced using a computer lan
 guage. Before it can control a computer, source code must be
 translated into machine language, either by a compiler or a
 translator program. See also compiler.

                                1-17

OS-9 Glossary
stack. A storage area in your computer's memory in which
 data can be placed or recovered in sequence, from one end only.

 standard error path. The route through which your computer
 sends error codes and other messages to the screen.

 standard input. path. The route through which you can send
 data to your computer (usually the keyboard).

 standard output path. The route your computer uses to send
 data to the screen.
 start up. To turn on your computer and initialize OS-9.

 stop bits. One or two bits that a terminal program sends after
 each unit of data to indicate that the transmission of the unit is
 complete.
 string. A group of alphanumeric characters.

 string data type. A type of variable that can contain one or
 more ASCII values (values representing alphanumeric characters
 or other symbols). String data types can be any length, up to the
 capacity of your computer's memory.

 structured programming. Building a program out of a series
 of procedures, each of which performs a specific task but com
 bines with its associated procedures as one program.

 subdirectory. A directory that resides within another (parent)
 directory.

 subroutine. An operation that performs a specific task as part
 of a larger operation.

 super user. The system user who has control of the entire sys
 tem and access to all system fiIes and modules. User Number 0.

 symbolic debugging. An error correcting system that lets you
 pause program execution and view the current values of vari
 ables, using their program names.

 syntax. The rules for forming legal instructions for your
 computer. --

 system. (1) A group of fiIes and programs that provide you
 with control over your computer. (2) Your computer with all its
 attached devices.

 1-18
                          OS-9 Glossary


system call. Built-in OS-9 routines that perform particular
 functions, such as accessing disk fiIes, printing data on the
 screen, and so on.

 table. A storage area in memory or on disk containing ordered
 data to be used by a process or function.
 task. A unit of work performed by your computer.

 terminal. A computer or an electronic device, with a screen
 and keyboard, connected to your Color Computer 3. You can
 access OS-9 functions from a terminal in the same manner as
 you can access them from your Color Computer 3 keyboard.

 text files. Files containing printable characters, or the code
 representing such characters.

 text screen. A Type 1 or 2 screen. Text screens use hardware
 generation of characters (fonts are not definable) and are often
 referred to as hardware screens or windows. Text screens cannot
 display graphics. Text operations occur faster in text windows/
 screens than on graphic windows/screens.
 text window. Any window created on a hardware text screen.

 time slice. The period of time between system clock ticks. A
 tick occurs every 1/60th of a second.

 timesharing. A situation in which more than one person uses
 the same operating system.

 token. In the BASIC language, a numeric value that represents
 a keyword.

 trace. To display each procedure statement as it executes and
 view its results.

 tracks. Magnetically created concentric circles created on a
 disk for the storage of data. Tracks are established when you for
 mat a disk.

 transparent characters. Characters that display over screen
 images without erasing any of the area surrounding the
 characters.

 unlink. To remove a module (program) from your computer's
 memory.

 update mode. The condition of a file when it is open for both
 reading and writing.

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OS-9 Glossary
user ID. A number that identifies the operator to which a pro
 cess belongs.
 user number. See user ID.

 utility. A short program that performs a frequently required
 task, usually for the maintenance of your computer system or
 files.
 variable. A unit of storage with no fixed value. You define a
 variable and locate it in your computer's memory using a vari
 able name.
 VDG. Video Display Graphics.
 vector. A graphics line or portion of a line.
 verify. To check data for accuracy.

 wait state. A situation in which a process remains suspended
 until one of its child processes terminates or until it receives a
 wakeup signal from the system.

 wake up. To continue the execution of a process that has been
 suspended.

 wild card. A symbol that represents or takes the place of one
 or more other characters or symbols.
 WINDINT. Window interface.

 window. All or a portion of your video screen with specific for
 mats (columns, lines, size, colors, and so on) and type (graphics,
 text, or both). An area of a screen in which you can run a pro
 cess or which can receive input.
 word length. The number of bits to transmit as one unit.

 workspace. A portion of your computer's memory that
 BASIC09 establishes for the storage and manipulation of
 procedures.

 write. To transfer data from the computer's memory to a
 device.
 write permit. System permission to change the data in a file.

 write protect. A method of protecting a diskette so that your
 computer cannot change the data on it.

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