System console: Difference between revisions
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[[Image:KNOPPIX booting.png|thumb|Knoppix system console showing the boot process]] |
[[Image:KNOPPIX booting.png|thumb|Knoppix system console showing the boot process]] |
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One meaning of '''system console''', '''computer console''', '''root console''', '''[[computer operator|operator]]'s console''', or simply '''console''' is the text entry and display device for system administration messages, particularly those from the [[BIOS]] or [[boot loader]], the [[Kernel (computer science)|kernel]], from the [[init]] system and from the [[syslog|system logger]]. It is a physical device consisting of a keyboard and a screen, and traditionally is a [[text terminal]], but may also be a [[graphical terminal]]. System consoles are generalized to [[computer terminal]]s, which are abstracted respectively by [[virtual console]]s and [[terminal emulator]]s. Today communication with system consoles is generally done abstractly, via the [[standard streams]] ([[stdin]], [[stdout]], and [[stderr]]), but there may be system-specific interfaces, for example those used by the system kernel.<ref>{{Cite book|url=https://books.google.com/books?id=vLlQAAAAYAAJ&q=%22System+console%22+-wikipedia|title=KSR1 System Administration|date=1994|publisher=Kendall Square Research|language=en}}</ref>{{better source|date=June 2021}} |
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Another, older, meaning of system console, computer console, '''hardware console''', operator's console or simply console is a hardware component used by an operator to control the hardware, typically some combination of [[front panel]], keyboard/printer and keyboard/display. |
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==History== |
==History== |
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[[Image:IBM_1620_Model_1.jpg|thumb|[[IBM 1620]] console, with a typewriter and front panel]] |
[[Image:IBM_1620_Model_1.jpg|thumb|[[IBM 1620]] console, with a typewriter and front panel]] |
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Prior to the development of alphanumeric [[cathode ray tube|CRT]] system consoles, some computers such as the [[IBM 1620]] had console typewriters and [[front panel]]s while the very first programmable computer, the [[Manchester Baby]], used a combination of electromechanical switches and a CRT to provide console functions—the CRT displaying memory contents in binary by mirroring the machine's [[Williams tube|Williams-Kilburn tube]] CRT-based RAM. |
Prior to the development of alphanumeric [[cathode ray tube|CRT]] system consoles, some computers such as the [[IBM 1620]] had console typewriters and [[front panel]]s while the very first programmable computer, the [[Manchester Baby]], used a combination of electromechanical switches and a CRT to provide console functions—the CRT displaying memory contents in binary by mirroring the machine's [[Williams tube|Williams-Kilburn tube]] CRT-based RAM. |
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Some early operating systems supported either a single keyboard/print or keyboard/display device for controlling the OS. Some also supported a single alternate console, and some supported a [[hard copy|hardcopy]] console for retaining a record of commands, responses and other console messages. However, in the late 1960s it became common for operating systems to support many more consoles than 3, and operating systems began appearing in which the console was simply any terminal with a privileged user logged on. |
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On early [[minicomputer]]s, the console was a '''serial console''', an [[RS-232]] serial link to a [[computer terminal|terminal]] such as a [[ASR-33]] or later a [[DECwriter|DECWriter]] or [[Digital Equipment Corporation|DEC]] [[VT100]]. This terminal was usually kept in a secured room since it could be used for certain privileged functions such as halting the system or selecting which media to boot from. Large [[midrange computer|midrange system]]s, e.g. those from [[Sun Microsystems]], [[Hewlett-Packard]] and [[IBM]], still use serial consoles. In larger installations, the console ports are attached to multiplexers or network-connected multiport serial servers that let an operator connect a terminal to any of the attached servers. Today, serial consoles are often used for accessing [[headless system]]s, usually with a [[terminal emulator]] running on a [[laptop]]. Also, routers, enterprise [[network switch]]es and other telecommunication equipment have RS-232 serial console ports. |
On early [[minicomputer]]s, the console was a '''serial console''', an [[RS-232]] serial link to a [[computer terminal|terminal]] such as a [[ASR-33]] or later a [[DECwriter|DECWriter]] or [[Digital Equipment Corporation|DEC]] [[VT100]]. This terminal was usually kept in a secured room since it could be used for certain privileged functions such as halting the system or selecting which media to boot from. Large [[midrange computer|midrange system]]s, e.g. those from [[Sun Microsystems]], [[Hewlett-Packard]] and [[IBM]], still use serial consoles. In larger installations, the console ports are attached to multiplexers or network-connected multiport serial servers that let an operator connect a terminal to any of the attached servers. Today, serial consoles are often used for accessing [[headless system]]s, usually with a [[terminal emulator]] running on a [[laptop]]. Also, routers, enterprise [[network switch]]es and other telecommunication equipment have RS-232 serial console ports. |
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Revision as of 14:26, 14 December 2021
One meaning of system console, computer console, root console, operator's console, or simply console is the text entry and display device for system administration messages, particularly those from the BIOS or boot loader, the kernel, from the init system and from the system logger. It is a physical device consisting of a keyboard and a screen, and traditionally is a text terminal, but may also be a graphical terminal. System consoles are generalized to computer terminals, which are abstracted respectively by virtual consoles and terminal emulators. Today communication with system consoles is generally done abstractly, via the standard streams (stdin, stdout, and stderr), but there may be system-specific interfaces, for example those used by the system kernel.[1][better source needed]
Another, older, meaning of system console, computer console, hardware console, operator's console or simply console is a hardware component used by an operator to control the hardware, typically some combination of front panel, keyboard/printer and keyboard/display.
History
Prior to the development of alphanumeric CRT system consoles, some computers such as the IBM 1620 had console typewriters and front panels while the very first programmable computer, the Manchester Baby, used a combination of electromechanical switches and a CRT to provide console functions—the CRT displaying memory contents in binary by mirroring the machine's Williams-Kilburn tube CRT-based RAM.
Some early operating systems supported either a single keyboard/print or keyboard/display device for controlling the OS. Some also supported a single alternate console, and some supported a hardcopy console for retaining a record of commands, responses and other console messages. However, in the late 1960s it became common for operating systems to support many more consoles than 3, and operating systems began appearing in which the console was simply any terminal with a privileged user logged on.
On early minicomputers, the console was a serial console, an RS-232 serial link to a terminal such as a ASR-33 or later a DECWriter or DEC VT100. This terminal was usually kept in a secured room since it could be used for certain privileged functions such as halting the system or selecting which media to boot from. Large midrange systems, e.g. those from Sun Microsystems, Hewlett-Packard and IBM, still use serial consoles. In larger installations, the console ports are attached to multiplexers or network-connected multiport serial servers that let an operator connect a terminal to any of the attached servers. Today, serial consoles are often used for accessing headless systems, usually with a terminal emulator running on a laptop. Also, routers, enterprise network switches and other telecommunication equipment have RS-232 serial console ports.
On PCs and workstations, the computer's attached keyboard and monitor have the equivalent function. Since the monitor cable carries video signals, it cannot be extended very far. Often, installations with many servers therefore use keyboard/video multiplexers (KVM switches) and possibly video amplifiers to centralize console access. In recent years, KVM/IP devices have become available that allow a remote computer to view the video output and send keyboard input via any TCP/IP network and therefore the Internet.
Some PC BIOSes, especially in servers, also support serial consoles, giving access to the BIOS through a serial port so that the simpler and cheaper serial console infrastructure can be used. Even where BIOS support is lacking, some operating systems, e.g. FreeBSD and Linux, can be configured for serial console operation either during bootup, or after startup.
It is usually possible to log in from the console. Depending on configuration, the operating system may treat a login session from the console as being more trustworthy than a login session from other sources.
See also
- Command-line interface (CLI)
- Console application
- Console server
- Linux console
- Virtual console
- Win32 console
References
- ^ KSR1 System Administration. Kendall Square Research. 1994.
External links
Media related to System console at Wikimedia Commons
