glossary(9) glossary(9)
NAME [Toc] [Back]
glossary - description of common HP-UX terms
DESCRIPTION [Toc] [Back]
HP-UX and other UNIX-like systems use a specialized vocabulary in
which certain words and terms have very specific meanings. This
glossary is intended as an aid in promoting exactness in use of these
specialized terms whose meanings sometimes differ from those that
might be encountered in other environments. References to other HP-UX
documentation are included as appropriate.
Entities in italics with a following parenthesized roman number
(sometimes with a capital letter), such as sh(1), wait(2), or
fopen(3S) refer to entries in the other sections of this manual.
Items in bold face refer to other entries in this glossary. Items in
computer font (bold face in the online manpages) are literals, such as
file names and environment variables. Any italicized manual names
refer to separate manuals that are either included with your system or
available separately.
The definitions specifically reflect the HP-UX operating system,
although some terms and definitions are also derived from those in the
emerging IEEE POSIX standards and the X/Open Portability Guide.
Differences in wording exist to more specifically reflect the
characteristics of the HP-UX system.
GLOSSARY ENTRIES [Toc] [Back]
. (dot) A special file name that refers to the current
directory. It can be used alone or at the beginning of
a directory path name. See also path name resolution.
The dot also functions as a special command in the
POSIX, Bourne, and Korn shells, and has special meaning
in text editors and formatters, in parsing regular
expressions and in designating file names.
.. (dot-dot) A special file name that refers to the parent
directory. If it begins a path name, dot-dot refers to
the parent of the current directory. If it occurs in a
path name, dot-dot refers to the parent directory of
the directory preceding dot-dot in the path name
string. As a special case, dot-dot refers to the
current directory in any directory that has no parent
(most often, the root directory). See also path name
resolution.
.o (dot-oh) The suffix customarily given to a relocatable object
file. The term dot-oh file is sometimes used to refer
to a relocatable object file. The format of such files
is sometimes called dot-oh format. See a.out(4).
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a.out The name customarily given to an executable object code
file on HP-UX. The format is machine-dependent, and is
described in a.out(4) for each implementation. Object
code that is not yet linked has the same format, but is
referred to as a .o (dot-oh) file. a.out is also the
default output file name used by the linker, ld(1).
absolute path name
A path name beginning with a slash (/). It indicates
that the file's location is given relative to the root
directory (/), and that the search begins there.
access The process of obtaining data from or placing data in
storage, or the right to use system resources.
Accessibility is governed by three process
characteristics: the effective user ID, the effective
group ID, and the group access list. The access(2)
system call determines accessibility of a file
according to the bit pattern contained in its amode
parameter, which is constructed to read, write, execute
or check the existence of a file. The access(2) system
call uses the real user ID instead of the effective
user ID and the real group ID instead of the effective
group ID.
access groups The group access list is a set of supplementary group
IDs used in determining resource accessibility. Access
checks are performed as described below in file access
permissions.
access mode An access mode is a form of access permitted to a file.
Each implementation provides separate read, write, and
execute/search access modes.
address A number used in information storage or retrieval to
specify and identify memory location. An address is
used to mark, direct, indicate destination, instruct or
otherwise communicate with computer elements.
In mail, address is a data structure whose format can
be recognized by all elements involved in transmitting
information. On a local system, this might be as
simple as the user's login name, while in a networked
system, address specifies the location of the resource
to the network software.
In a text editor (such as vi, ex, ed, or sed), an
address locates the line in a file on which a given
instruction is intended.
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For adb, the address specifies at what assemblylanguage
instruction to execute a given command.
In disk utilities such as fsdb, address might refer to
a raw or block special file, the inode number, volume
header, or other file attribute.
In the context of peripheral devices, address refers to
a set of values that specify the location of an I/O
device to the computer. The exact details of the
formation of an address differ between systems. On
Series 700 systems, the address consists of up to two
elements: the select code, and the function number.
address space The range of memory locations to which a process can
refer.
affiliation See terminal affiliation.
appropriate privileges
Each implementation provides a means of associating
privileges with a process for function calls and
function call options requiring special privileges. In
the HP-UX system, appropriate privileges refers either
to superuser status or to a privilege associated with
privilege groups (see setprivgrp(1M)).
archive A file comprised of the contents of other files, such
as a group of object files (that is, .o) used by the
linker, ld(1)). An archive file is created and
maintained by a
or cpio(1). An archive is often called a library.
ASCII An acronym for American Standard Code for Information
Interchange. ASCII is the traditional System V coded
character set and defines 128 characters, including
both control characters and graphic characters, each of
which is represented by 7-bit binary values ranging
from 0 through 127 decimal.
background process group
Any process group that is a member of a session which
has established a connection with a controlling
terminal that is not in the foreground process group.
backup The process of making a copy of all or part of the file
system in order to preserve it, in case a system crash
occurs (usually due to a power failure, hardware error,
etc.). This is a highly recommended practice.
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block (1) The fundamental unit of information HP-UX uses for
access and storage allocation on a mass storage medium.
The size of a block varies between implementations and
between file systems. In order to present a more
uniform interface to the user, most system calls and
utilities use block to mean 512 bytes, independent of
the actual block size of the medium. This is the
meaning of block unless otherwise specified in the
manual entry.
(2) On media such as 9-track tape that write variable
length strings of data, the size of those strings.
Block is often used to distinguish from record; a block
contains several records, whereas the number of records
denotes the blocking factor.
block special file
A special file associated with a mass storage device
(such as a hard disk or tape cartridge drive) that
transfers data in multiple-byte blocks, rather than by
series of individual bytes (see character special
file). Block special files can be mounted. A block
special file provides access to the device where
hardware characteristics of the device are not visible.
boot, boot-up The process of loading, initializing, and running an
operating system.
boot area A portion of a mass storage medium on which the volume
header and a ``bootstrap'' program used in booting the
operating system reside. The boot area is reserved
exclusively for use by HP-UX.
boot ROM A program residing in ROM (Read-Only Memory) that
executes each time the computer is powered up and is
designed to bring the computer to a desired state by
means of its own action. The first few instructions of
a bootstrap program are sufficient to bring the
remainder of the program into the computer from an
input device and initiate functions necessary for
computation. The function of the boot ROM is to run
tests on the computer's hardware, find all devices
accessible through the computer, and then load either a
specified operating system or the first operating
system found according to a specific search algorithm.
bus address A number which makes up part of the address HP-UX uses
to locate a particular device. The bus address is
determined by a switch setting on a peripheral device
which allows the computer to distinguish between two
devices connected to the same interface. A bus address
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is sometimes called a ``device address''.
character An element used for the organization, control, or
representation of text. Characters include graphic
characters and control characters.
character set A set of characters used to communicate in a native or
computer language.
character special file
A special file associated with I/O devices that
transfer data byte-by-byte. Other byte-mode I/O
devices include printers, nine-track magnetic tape
drives, and disk drives when accessed in ``raw'' mode
(see raw disk). A character special file has no
predefined structure.
child process A new process created by a pre-existing process via the
fork(2) system call. The new process is thereafter
known to the pre-existing process as its child process.
The pre-existing process is the parent process of the
new process. See parent process and fork.
clock tick A rate used within the system for scheduling and
accounting. It consists of the number of intervals per
second as defined by CLK_TCK that is used to express
the value in type clock_t. CLK_TCK was previously
known as the defined constant HZ.
coded character set
A set of unambiguous rules that establishes a character
set and the one-to-one relationship between each
character of the set and its corresponding bit
representation. ASCII is a coded character set.
collating element
The smallest entity used in collation to determine the
logical ordering of strings (that is, the collation
sequence). To accommodate native languages, a
collating element consists of either a single
character, or two or more characters collating as a
single entity. The current value of the LANG
environment variable determines the current set of
collating elements.
collation The logical ordering of strings in a predefined
sequence according to rules established by precedence.
These rules identify a collation sequence among the
collating elements and also govern the ordering of
strings consisting of multiple collating elements, to
accommodate native languages.
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collation sequence
The ordering sequence applied to collating elements
when they are sorted. To accommodate native languages,
collation sequence can be thought of as the relative
order of collating elements as set by the current value
of the LANG environment variable. Characters can be
omitted from the collation sequence, or two or more
collating elements can be given the same relative order
(see string(3C)).
command A directive to perform a particular task. HP-UX
commands are executed through a command interpreter
called a shell. HP-UX supports several shells,
including the POSIX shell (sh-posix(1)), the C shell
(csh(1)), and the Korn shell (ksh(1)). See sh(1) for
more information about supported shells. Most commands
are carried out by an executable file, called a
utility, which might take the form of a stand-alone
unit of executable object code (a program) or a file
containing a list of other programs to execute in a
given order (a shell script). Scripts can contain
references to other scripts, as well as to object-code
programs. A typical command consists of the utility
name followed by arguments that are passed to the
utility. For example, in the command, ``ls
mydirectory'', ``ls'' is the utility name and
``mydirectory'' is an argument passed to the ``ls''
utility.
command interpreter
A program which reads lines of text from standard input
(typed at the keyboard or read from a file), and
interprets them as requests to execute other programs.
A command interpreter for HP-UX is called a shell. See
sh(1) and related manual entries.
Command Set 1980 [Toc] [Back]
See CS/80.
composite graphic symbol
A graphic symbol consisting of a combination of two or
more other graphic symbols in a single character
position, such as a diacritical mark and a basic
letter.
control character
A character other than a graphic character that affects
the recording, processing, transmission, or
interpretation of text. In the ASCII character set,
control characters are those in the range 0 through 31,
and 127. Control characters can be generated by
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holding down the control key (which may be labeled
CTRL, CONTROL, or CNTL depending on your terminal), and
pressing a character key (as you would use SHIFT).
These two-key sequences are often written as, for
example, Control-D, Ctrl-D, or ^D, where ^ stands for
the control key.
controlling process
The session leader that establishes the connection to
the controlling terminal. Should the terminal
subsequently cease to be a controlling terminal for
this session, the session leader ceases to be the
controlling process.
controlling terminal
A terminal that is associated with a session. Each
session can have at most one controlling terminal
associated with it and a controlling terminal is
associated with exactly one session. Certain input
sequences from the controlling terminal cause signals
to be sent to all processes in the foreground process
group associated with the controlling terminal.
Coordinated Universal Time (UTC) [Toc] [Back]
See Epoch.
CS/80, CS-80 A family of mass storage devices that communicate with
the controlling computer by means of a series of
commands and data transfer protocol referred to as the
CS/80 (Command Set 1980) command set. This command set
was implemented in order to provide better
forward/backward compatibility between models and
generations of mass storage devices as technological
advances develop. Some mass storage devices support
only a subset of the full CS/80 command set, and are
usually referred to as SS/80 (Subset 1980) devices.
crash The unexpected shutdown of a program or system. If the
operating system crashes, this is a ``system crash'',
and requires the system to be re-booted.
current directory
See working directory.
current working directory
See working directory.
daemon A process which runs in the background, and which is
usually immune to termination instructions from a
terminal. Its purpose is to perform various
scheduling, clean-up, and maintenance jobs.
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lpsched(1M) is an example of a daemon. It exists to
perform these functions for line printer jobs queued by
lp(1). An example of a permanent daemon (that is, one
that should never die) is cron(1M).
data encryption
A method for encoding information in order to protect
sensitive or proprietary data. For example, HP-UX
automatically encrypts all users' passwords. The
encryption method used by HP-UX converts ASCII text
into a base-64 representation using the alphabet ., /,
0-9, A-Z, a-z. See passwd(4) for the numerical
equivalents associated with this alphabet.
default search path
The sequence of directory prefixes that sh(1), time(1),
and other HP-UX commands apply in searching for a file
known by an relative path name (that is, a path name
not beginning with a slash (/)). It is defined by the
environment variable PATH (see environ(5)). login(1)
sets PATH equal to :/usr/bin, which means that your
working directory is the first directory searched,
followed by /usr/bin. The search path can be redefined
by modifying the value of PATH. This is usually done
in /etc/profile, and/or in the .profile file found in
the home directory.
defunct process
See zombie process.
delta A term used in the Source Code Control System (SCCS) to
describe a unit of one or more textual changes to an
SCCS file. Each time an SCCS file is edited, changes
made to the file are stored separately as a delta. The
get(1) command is then used to specify which deltas are
to be applied to or excluded from the SCCS file, thus
yielding a particular version of the file. Contrast
this with the vi or ed editor, which incorporates
changes into the file immediately, eliminating any
possibility of obtaining a previous version of that
file. A similar capability is provided by RCS files
(see rcsintro(5)).
demon Improper spelling of the UNIX word daemon.
device A computer peripheral or an object that appears to an
application as such.
device address See bus address.
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device file See special file.
directory A file that provides the mapping between the names of
files and their contents, and is manipulated by the
operating system alone. For every file name contained
in a directory, that directory contains a pointer to
the file's inode; The pointer is called a link. A file
can have several links appearing anywhere on the same
file system. Each user is free to create as many
directories as needed (using mkdir(1)), provided that
the parent directory of the new directory gives the
permission to do so. Once a directory has been
created, it is ready to contain ordinary files and
other directories. An HP-UX directory is named and
behaves exactly like an ordinary file, with one
exception: no user (including the superuser) is allowed
to write data on the directory itself; this privilege
is reserved for the HP-UX operating system.
By convention, a directory contains at least two links,
. and .., referred to as dot and dot-dot respectively.
Dot refers to the directory itself and dot-dot refers
to its parent directory. A directory containing only .
and .. is considered empty.
dot See . (dot).
dot-dot See .. (dot-dot).
dot-oh See .o (dot-oh).
dot-oh file See .o (dot-oh).
dot-oh format See .o (dot-oh).
downshifting The conversion of an uppercase character to its
lowercase representation.
dynamic loader A routine invoked at process startup time that loads
shared libraries into a process' address space. The
dynamic loader also resolves symbolic references
between a program and the shared libraries, and
initializes the shared libraries' linkage tables. See
dld.sl(5) (PA-RISC systems) or dld.so(5) (Itanium(R)-
based systems) for details.
effective group ID
Every process has an effective group ID that is used to
determine file access permissions. A process's
effective group ID is determined by the file (command)
that process is executing. If that file's set-group-ID
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bit is set (located in the mode of the file, see mode),
the process's effective group ID is set equal to the
file's group ID. This makes the process appear to
belong to the file's group, perhaps enabling the
process to access files that must be accessed in order
for the program to execute successfully. If the file's
set-group-ID bit is not set, the process's effective
group ID is inherited from the process's parent. The
setting of the process's effective group ID lasts only
as long as the program is being executed, after which
the process's effective group ID is set equal to its
real group ID. See group, real group ID, and set-
group-ID bit.
effective user ID
A process has an effective user ID that is used to
determine file access permissions (and other
permissions with respect to system calls, if the
effective user ID is 0, which means superuser). A
process's effective user ID is determined by the file
(command) that process is executing. If that file's
set-user-ID bit is set (located in the mode of the
file, see mode), the process's effective user ID is set
equal to the file's user ID. This makes the process
appear to be the file's owner, enabling the process to
access files which must be accessed in order for the
program to execute successfully. (Many HP-UX commands
which are owned by root, such as mkdir and mail, have
their set-user-ID bit set so other users can execute
these commands.) If the file's set-user-ID bit is not
set, the process's effective user ID is inherited from
that process's parent. See real user ID and set-user-
ID bit.
end-of-file (EOF)
(1) The data returned when attempting to read past the
logical end of a file via stdio(3S) routines. In this
case, end-of-file is not properly a character.
(2) The ASCII character Ctrl-D.
(3) A character defined by stty(1) or ioctl(2) (see
termio(7)) to act as end-of-file on your terminal.
Usually this is Ctrl-D.
(4) The return value from read(2) that indicates end of
data.
environment The set of defined shell variables (such as EXINIT,
HOME, PATH, SHELL, TERM, and others) that define the
conditions under which user commands run. These
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conditions can include user terminal characteristics,
home directory, and default search path. Each shell
variable setting in the current process is passed on to
all child processes that are created, provided that
each shell variable setting has been exported via the
export command (see sh(1)). Unexported shell variable
settings are meaningful only to the current process,
and any child processes created get the default
settings of certain shell variables by executing
/etc/profile, $HOME/.profile, or $HOME/.login.
EOF See end-of-file.
Epoch The time period beginning at 0 hours, 0 minutes, 0
seconds, Coordinated Universal Time (UTC) on January 1,
1970. Increments quantify the amount of time elapsed
from the Epoch to the referenced time.
Leap seconds, which occur at irregular intervals, are
not reflected in the count of seconds between the Epoch
and the referenced time. (Fourteen leap seconds
occurred in the years 1970 through 1988.)
FIFO special file [Toc] [Back]
A type of file. Data written to a FIFO is read on a
first-in-first-out basis. Other characteristics are
described in open(2), read(2), write(2) and lseek(2).
file A stream of bytes that can be written to and/or read
from. A file has certain attributes, including
permissions and type. File types include regular file,
character special file, block special file, FIFO
special file, network special file, directory, and
symbolic link. Every file must have a file name that
enables the user (and many of the HP-UX commands) to
refer to the contents of the file. The system imposes
no particular structure on the contents of a file,
although some programs do. Files can be accessed
serially or randomly (indexed by byte offset). The
interpretation of file contents and structure is up to
the programs that access the file.
file access mode
A characteristic of an open file description that
determines whether the described file is open for
reading, writing, or both. (See open(2).)
file access permissions
Every file in the file hierarchy has a set of access
permissions. These permissions are used in determining
whether a process can perform a requested operation on
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the file (such as opening a file for writing). Access
permissions are established when a file is created via
the open(2) or creat(2) system calls, and can be
changed subsequently through the chmod(2) call. These
permissions are read by stat(2) or fstat(2).
File access controls whether a file can be read,
written, or executed. Directory files use the execute
permission to control whether or not the directory can
be searched.
File access permissions are interpreted by the system
as they apply to three different classes of users: the
owner of the file, the users in the file's group, and
anyone else (``other''). Every file has an independent
set of access permissions for each of these classes.
When an access check is made, the system decides if
permission should be granted by checking the access
information applicable to the caller.
Read, write, and execute/search permissions on a file
are granted to a process if any of the following
conditions are met:
+ The process's effective user ID is superuser.
+ The process's effective user ID matches the
user ID of the owner of the file and the
appropriate access bit of the owner portion
(0700) of the file mode is set.
+ The process's effective user ID does not match
the user ID of the owner of the file, and
either the process's effective group ID matches
the group ID of the file, or the group ID of
the file is in the process's group access list,
and the appropriate access bit of the group
portion (070) of the file mode is set.
+ The process's effective user ID does not match
the user ID of the owner of the file, and the
process's effective group ID does not match the
group ID of the file, and the group ID of the
file is not in the process's group access list,
and the appropriate access bit of the ``other''
portion (07) of the file mode is set.
Otherwise, the corresponding permissions are denied.
file descriptor
A small unique, per-process, nonnegative integer
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identifier that is used to refer to a file opened for
reading and/or writing. Each file descriptor refers to
exactly one open file description.
A file descriptor is obtained through system calls such
as creat(2), fcntl(2), open(2), pipe(2), or dup(2).
The file descriptor is used as an argument by calls
such as read(2), write(2), ioctl(2), and close(2).
The value of a file descriptor has a range from 0 to
one less than the system-defined maximum. The systemdefined
maximum is the value NOFILE in <sys/param.h>.
file group class
A process is in the file group class of a file if the
process is not the file owner class and if the
effective group ID or one of the supplementary group
IDs of the process matches the group ID associated with
the file.
file hierarchy The collection of one or more file systems available on
a system. All files in these file systems are
organized in a single hierarchical structure in which
all of the nonterminal nodes are directories. Because
multiple links can refer to the same file, the
directory is properly described as a directed graph.
file name A string of up to 14 bytes (or 255 bytes on file
systems that support long file names) used to refer to
an ordinary file, special file, or directory. The byte
values NUL (null) and slash (/) cannot be used as
characters in a file name. Note that it is generally
unwise to use *, ?, ,, [, or ] as part of file names
because the shell attaches special meaning to these
characters (see sh(1), csh(1), or ksh(1)). Avoid
beginning a file name with -, +, or =, because to some
programs, these characters signify that a command
argument follows. A file name is sometimes called a
path name component. Although permitted, it is
inadvisable to use characters that do not have a
printable graphic on the hardware you commonly use, or
that are likely to confuse your terminal.
file name portability
File names should be constructed from the portable file
name character set because the use of other characters
can be confusing or ambiguous in certain contexts.
file offset The file offset specifies the position in the file
where the next I/O operation begins. Each open file
description associated with either a regular file or
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special file has a file offset. There is no file
offset specified for a pipe or FIFO.
file other class
A process is in the file other class if the process is
not in the file owner class or file group class.
file owner class
A process is in the file owner class if the effective
user ID of the process matches the user ID of the file.
file permission bits
See permission bits.
file pointer A data element obtained through any of the fopen(3S)
standard I/O library routines that ``points to''
(refers to) a file opened for reading and/or writing,
and which keeps track of where the next I/O operation
will take place in the file (in the form of a byte
offset relative to the beginning of the file). After
obtaining the file pointer, it must thereafter be used
to refer to the open file when using any of the
standard I/O library routines. (See stdio(3S) for a
list of these routines.)
file serial number
A file-system-unique identifier for a given file, also
known as the file's inode number. Each file serial
number identifies exactly one inode. File serial
numbers are not necessarily unique across file systems
in the file hierarchy.
file status flags
Part of an open file description. These flags can be
used to modify the behavior of system calls that access
the file described by the open file description.
file system A collection of files and supporting data structures
residing on a mass storage volume. A file system
provides a name space for file serial numbers referring
to those files. Refer to the System Administrator
manuals supplied with your system for details
concerning file system implementation and maintenance.
file times update
Each file has three associated time values that are
updated when file data is accessed or modified, or when
the file status is changed. These values are returned
in the file characteristics structure, as described in
<sys/stat.h>. For each function in HP-UX that reads or
writes file data or changes the file status, the
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appropriate time-related files are noted as ``markedfor-update''.
When an update point occurs, any marked
fields are set to the current time and the update marks
are cleared. One such update point occurs when the
file is no longer open for any process. Updates are
not performed for files on read-only file systems.
filter A command that reads data from the standard input,
performs a transformation on the data, and writes it to
the standard output.
foreground process group
Each session that has established a connection with a
controlling terminal has exactly one process group of
the session as a foreground process group of that
controlling terminal. The foreground process group has
certain privileges when accessing its controlling
terminal that are denied to background process groups.
See read(2) and write(2).
foreground process group ID
The process group ID of the foreground process group.
fork An HP-UX system call (see fork(2)), which, when invoked
by an existing process, causes a new process to be
created. The new process is called the child process;
the existing process is called the parent process. The
child process is created by making an exact copy of the
parent process. The parent and child processes are
able to identify themselves by the value returned by
their corresponding fork call (see fork(2) for
details).
function number
On Series 700 systems, when two or more interfaces
reside on a single interface card, each interface is
treated as a separate function and is assigned a
corresponding unique function number.
graphic character
A character other than a control character that has a
visual representation when hand-written, printed, or
displayed.
group See group ID.
group ID Associates zero or more users who must all be permitted
to access the same set of files. The members of a
group are defined in the files /etc/passwd and
/etc/logingroup (if it exists) via a numerical group ID
that must be between zero and UID_MAX, inclusive.
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Users with identical group IDs are members of the same
group. An ASCII group name is associated with each
group ID in the file /etc/group. A group ID is also
associated with every file in the file hierarchy, and
the mode of each file contains a set of permission bits
that apply only to this group. Thus, if you belong to
a group that is associated with a file, and if the
appropriate permissions are granted to your group in
the file's mode, you can access the file. When the
identity of a group is associated with a process, a
group ID value is referred to as a real group ID, an
effective group ID, a supplementary group ID, or a
saved group ID. See also privileged group and set-
group-ID bit.
group access list
A set of supplementary group IDs used in determining
resource accessibility. Access checks are performed as
described in file access permissions.
hierarchical directory
A directory (or file system) structure in which each
directory can contain other directories as well as
files.
home directory The directory name given by the value of the
environment variable HOME. When you first log in,
login(1) automatically sets HOME to your login
directory. You can change its value at any time. This
is usually done in the .profile file contained in your
login directory. Setting HOME does not affect your
login directory; it simply gives you a convenient way
of referring to what is probably your most commonly
used directory.
host name An ASCII string of at most 8 characters (of which only
6 are supported by all the various manufacturers'
UNIX-like operating systems) which uniquely identifies
an HP-UX system on a uucp(1) network. The host name
for your system can be viewed and/or set with the
hostname(1) command. Systems without a defined host
name are described as ``unknown'' on the uucp(1)
network. Do not confuse a host name with a node name,
which is a string that uniquely identifies an HP-UX
system on a Local Area Network (LAN). Although your
host and node names may be identical, they are set and
used by totally different software. See node name.
image The current state of your computer (or your portion of
the computer, on a multiuser system) during the
execution of a command. Often thought of as a
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``snapshot'' of the state of the machine at any
particular moment during execution.
init A system process that performs initialization, is the
ancestor of every other process in the system, and is
used to start login processes. init usually has a
process ID of 1. See init(1M).
interleave factor
A number that determines the order in which sectors on
a mass storage medium are accessed. It can be
optimized to make data acquisition more efficient.
inode An inode is a structure that describes a file and is
identified in the system by a file serial number.
Every file or directory has associated with it an
inode. Permissions that specify who can access the
file and how are kept in a 9-bit field that is part of
the inode. The inode also contains the file size, the
user and group ID of the file, the number of links, and
pointers to the disk blocks where the file's contents
can be found. Each connection between an inode and its
entry in one or more directories is called a link.
inode number See file serial number.
Internal Terminal Emulator (ITE) [Toc] [Back]
The ``device driver'' code contained in the HP-UX
kernel that is associated with the computer's built-in
keyboard and display or with a particular keyboard and
display connected to the computer, depending on the
Series and Model of system processor. See system
console and the System Administrator manuals supplied
with your system for details.
internationalization
The concept of providing software with the ability to
support the native language, local customs, and coded
character set of the user.
interrupt signal
The signal sent by SIGINT (see signal(2)). This signal
generally terminates whatever program you are running.
The key which sends this signal can be redefined with
ioctl(2) or stty(1) (see termio(7)). It is often the
ASCII DEL (rubout) character (the DEL key) or the BREAK
key. Ctrl-C is often used instead.
intrinsic See system call.
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I/O redirection
A mechanism provided by the HP-UX shell for changing
the source of data for standard input and/or the
destination of data for standard output and standard
error. See sh(1).
ITE See Internal Terminal Emulator.
job control Job control allows users to selectively stop (suspend)
execution of processes and continue (resume) their
execution at a later time.
The user employs this facility via the interactive
interface jointly supplied by the system terminal
driver and certain shells (see sh(1)). The terminal
driver recognizes a user-defined ``suspend character'',
which causes the current foreground process group to
stop and the user's job control shell to resume. The
job control shell provides commands that continue
stopped process groups in either the foreground or
background. The terminal driver also stops a
background process group when any member of the
background process group attempts to read from or write
to the user's terminal. This allows the user to finish
or suspend the foreground process group without
interruption and continue the stopped background
process group at a more convenient time.
See stty(1), sh(1), and related shell entries for usage
and installation details, and the shell entries plus
signal(2) and termio(7) for implementation details.
kernel The HP-UX operating system. The kernel is the
executable code responsible for managing the computer's
resources, such as allocating memory, creating
processes, and scheduling programs for execution. The
kernel resides in RAM (random access memory) whenever
HP-UX is running.
LANG An environment variable used to inform a computer
process of the user's requirements for native language,
local customs, and coded character set.
library A file containing a set of subroutines and variables
that can be accessed by user programs. Libraries can
be either archives or shared libraries. For example,
/usr/lib/libc.a and /usr/lib/libc.sl are libraries
containings all functions of Section 2 and all
functions of Section 3 that are marked (3C) and (3S) in
the HP-UX Reference. Similarly, /usr/lib/libm.a and
/usr/lib/libm.sl are libraries containing all functions
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in Section 3 that are marked
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