- Asynchronous
- An event that may take place at any time. See synchronous.
- BASIC
-
Beginners All-purpose Symbolic Instruction Code. A simple computer
language.
- Blocked
-
Refers to a process waiting for some event to occur. Processes can
block on terminal I/O, signals, and other IPC and I/O functions.
- Console
- The terminal which represents the IIGS's keyboard and monitor.
- Context
- The attributes which define the state of a process. This includes
the program counter, stack pointer, and other machine registers (both
CPU and other computer hardware).
- Controlling terminal
-
The terminal which “controls” a process or process group;
processes can receive keyboard signals (such as SIGTSTP, or
ˆZ)
only from their controlling terminal.
- Critical Section
- A piece of code inside which only one process at a time may
be allowed to execute. Critical sections are usually protected by
semaphores.
- Daemon
-
A process that runs in the background and
waits to act on an
asynchronous event. These can be anything: waiting for a caller
on a modem, waiting for spooled files to print, etc. Daemons
are usually started at boot time by the initd(8)
process.
- Deadlock
-
A situation where two or more communicating processes are blocked,
waiting on each other. See Chapter 5, “Deadlock”.
- Errno
- A variable which holds a descriptive numeric error code,
returned from C libraries and system calls.
- Foobar, foo, bar
- Foobar derives from an old military acronym FUBAR. In it's politest
interpretation it stands for Fouled Up Beyond All Recognition.
Computer scientists borrowed the term and created foobar.
When a name for an object in a code fragment is needed but the
name itself is not important, foo and bar are first choice among
computing science types. They should not be used in production
code.
- Executable
- A program as it resides on disk. Executables can be compiled or
assembled programs, or shell scripts. Executables are run by
typing their name on the shell's command line and frequently take
paramters to determine what data they operate on and particulars
of how they do it.
- GNO/ME
- GNO Multitasking Environment. The complete package including the GNO
kernel and the GNO Shell.
- GNO Kernel
- Heart of GNO/ME. Executes processes when asked by the GNO Shell.
- GNO Shell
- Provides an interface between the user and the GNO kernel.
- gsh
- GNO Implementation of a UNIX-like shell.
- GS/OS
- A 16 bit Operating System for the Apple IIgs.
- IPC
- “Inter-Process Communication”. Any method by which processes
can pass information to other processes.
- Job
-
A set of related processes. Jobs are generally composed of
processes with a common parent and the same controlling terminal.
- Manpage
- Refers to the system call and utility documentation provided with GNO.
Manpages exist on disk as either nroff(1) or aroff(1)
source. They can also be preformatted by catman(1). They
can be viewed by various utilites on a variety of output devices.
- Master
-
Refers to the .PTYxx side of a pseudo-terminal, and also
the process controlling that device. The master is usually responsible
for setting up the PTY and running a process on it.
- Message
- A 32-bit value that is passed via the Messages IPC mechanism to
another process.
- Mutex
-
Short for mutual exclusion, a term that refers to protecting a
critical section.
- Panic
- An unrecoverable kernel error, usually indicating that an
internal data structure has become corrupted.
- Parent
- When talking about a process, the parent of a process is the one that
spawned it; i.e., made the fork(2) system call.
- Pipe
- A unidirectional IPC mechanism. Pipes transmit binary 8-bit data.
- Pipeline
- Two or more processes connected by pipes.
- Port
- A flow-controlled IPC mechanism that can pass longwords of data.
- Process
- A program in execution.
- Process Group
- An identifying code for a job. Process groups are also assigned
to TTYs, which allows the TTY to differentiate
background jobs from foreground jobs when sending interrupt signals.
- Pseudo-terminal
- A bidirectional communications channel, normally used in windowing
systems or for advanced control and testing applications.
- PTY
- See 'pseudo-terminal'.
- Semaphore
- A data object used to synchronize concurrent processes.
- Sequentialization
-
The task of ensuring that critical sections are only executed by one
concurrent process at a time.
- Signal
- A software interrupt and IPC mechanism.
- Slave
- 1. A good term to describe the relationship of Joe Citizen to the IRS.
2. The .TTYxx side of a pseudo-terminal; the slave
is usually an application program of some kind, like a shell.
- Suspended
- Refers to a process whose execution has been stopped.
- Synchronous
- An event that takes place at a predetermined time or sequence of times.
Also used to indicate the act of waiting for an event to happen. See
asynchronous.
- Terminal
- Any device that looks like a terminal; this includes pseudo-ttys. By
definition, a terminal supports all of the tty(4)
ioctl calls.
- Tty
- Short for Teletype. TTY is an anachronistic term; in modern usage
it is taken to mean “terminal”.
- UNIX
- Popular operating system which has growing use in education and
business. One of the first operating systems to support multitasking.
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