computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, ...

, a status key is a keyboard key that causes an

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

and/or a program to output status information on a terminal when it is pressed. In the event that a program on a terminal produces no indications that it is running, typing the status key will reveal the program's state and activity. Older implementations produced only a quick one-line status report for the current job when the status key was pressed. Newer implementations support sending a

signal In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The '' IEEE Transactions on Signal Processing' ...

to the current process to allow the application to report on status as well.

Implementations

Several different operating systems have a status key feature.

DEC RSTS/E

RSTS/E is documented as having a status key at least as far back as 1977 and it continued to have one into at least the 1980s. Typing the status key results in output that is represented by the following example: 18 GARP::KB32 SYSTAT+BAS4F ^C(0R) 11(16)K+ 16K 3.3(+5)

DEC TOPS-10

TOPS-10 TOPS-10 System (''Timesharing / Total Operating System-10'') is a discontinued operating system from Digital Equipment Corporation (DEC) for the PDP-10 (or DECsystem-10) mainframe computer family. Launched in 1967, TOPS-10 evolved from the earlier ...

when the CTRL/T (control-T) key is pressed, the monitor prints status information pertaining to the job on the terminal. Typing CTRL/T displays a job's progress without interrupting its execution. No representation of a control-t character is displayed on the terminal, just the status information. DAY: :05:43 RUN:0.48 RD:75 WR:8 SOS 12+19p ^C Ctx:1 PC:400275 ''Incremental'' values in the table below indicate that the value is the accumulation since login or last CTRL/T whichever was shortest.

DEC TOPS-20

TOPS-20 The TOPS-20 operating system by Digital Equipment Corporation (DEC) is a proprietary OS used on some of DEC's 36-bit mainframe computers. The Hardware Reference Manual was described as for "DECsystem-10/DECSYSTEM-20 Processor" (meaning the DEC PD ...

reports a shorter list of information than its predecessors: 09:36:35 TEST Running at 404157 Used 0:00:35.8 in 0:30:39, Load 4.04

MIT ITS

ITS copied the idea from

, but used the key sequence . 19:29:10 3 RMS HACTRN EMACS1 130566

VSI OpenVMS

OpenVMS OpenVMS, often referred to as just VMS, is a multi-user, multiprocessing and virtual memory-based operating system. It is designed to support time-sharing, batch processing, transaction processing and workstation applications. Customers using Ope ...

has a status key which can be customized and works with remote processes. The default output includes these items: NODE22::SMITH 16:21:04 (DCL) CPU=00:03:29.39 PF=14802 IO=18652 MEM=68

BSD UNIX

4.3BSD-Reno The History of the Berkeley Software Distribution begins in the 1970s. 1BSD (PDP-11) The earliest distributions of Unix from Bell Labs in the 1970s included the source code to the operating system, allowing researchers at universities to modify ...

and BSD systems derived from that version and OSF/1 have a status key which defaults to Ctrl-T and can be assigned to any key. It sends

SIGINFO Signals are standardized messages sent to a running program to trigger specific behavior, such as quitting or error handling. They are a limited form of inter-process communication (IPC), typically used in Unix, Unix-like, and other POSIX-compli ...

to the current process which is ignored by default but can be configured to call a function which can display status information from the program. load: 0.10 cmd: sleep 1594 anslp1.33r 0.00u 0.00s 0% 1864k

Apple macOS

Because

XNU XNU is the computer operating system (OS) kernel developed at Apple Inc. since December 1996 for use in the Mac OS X (now macOS) operating system and released as free and open-source software as part of the Darwin OS, which in addition to macOS ...

has a

FreeBSD FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular ...

kernel which has been modified to be a Mach server process, the terminal driver includes a status key which is inherited. load: 3.04 cmd: sleep 719 waiting 0.00u 0.00s

References

{{reflist Computer keys System monitors