| 词条 | Virtual console |
| 释义 |
A virtual console (VC) – also known as a virtual terminal (VT) – is a conceptual combination of the keyboard and display for a computer user interface. It is a feature of some Unix-like operating systems such as BSD, Linux, illumos and UnixWare in which the system console of the computer can be used to switch between multiple virtual consoles to access unrelated user interfaces. Virtual consoles date back at least to Xenix[1] and Concurrent CP/M in the 1980s.[2] In the Linux console and other platforms, usually the first six virtual consoles provide a text terminal with a login prompt to a Unix shell. The graphical X Window System starts in the seventh virtual console. In Linux, the user switches between them by pressing the Alt key combined with a function key – for example {{key press|Alt}} + {{key press|F1}} to access the virtual console number 1. {{key press|Alt}} + {{key press|Left}} changes to the previous virtual console and {{key press|Alt}} + {{key press|Right}} to the next virtual console. To switch from the X Window System, {{key press|Ctrl}} + {{key press|Alt}} + {{key press|F1}} works. (Note that users can redefine these default key combinations.) If several sessions of the X Window System are required to run in parallel, such as in the case of fast user switching or when debugging X programs on a separate X server, each X session usually runs in a separate virtual console. GNU Screen is a program that can change between several text-mode programs in one textual login. InterfaceThe virtual consoles are represented by device special files ) The virtual consoles can be configured in the file Programs used to access the virtual consoles typically include:
The program startx starts the X Window System on a new virtual console. There are also other graphical programs that can start from the console, such as LinuxTV and MPlayer. Programs can access the virtual consoles by the device special files. In text mode, writing to the file displays text on the virtual console and reading from the file returns text the user writes to the virtual console. As with other text terminals, there are also special escape sequences, control characters and Unix systemsUnix workstations, such as those manufactured by Sun or Silicon Graphics, did not include virtual consoles. The only purpose of a console would be to fix the system so that the graphical environment could start. Sun Niagara-based servers running virtualization with Logical Domains get virtual console services from the Control domain. See also
Notes1. ^{{cite web |url=http://www.freepatentsonline.com/4945468.html |title=Trusted path mechanism for virtual terminal environments |publisher= FreePatentsOnline.com |accessdate=2008-04-09}} United States Patent 4945468 lists Xenix as prior art in this area. 2. ^{{cite news | url=https://archive.org/stream/byte-magazine-1983-11/1983_11_BYTE_08-11_Inside_the_IBM_PC#page/n263/mode/2up | title=Concurrent CP/M | work=BYTE | date=November 1983 | accessdate=19 March 2016 | author=Guzaitis, Joe | pages=257-268}} 3. ^{{cite web|url= http://tldp.org/HOWTO/Keyboard-and-Console-HOWTO-20.html|title= Screen dumps|accessdate= 2008-07-31|author= |last= |first= |authorlink= |coauthors= |date= |year= |month= |work= The Linux keyboard and console HOWTO|publisher= The Linux Documentation Project|quote= The current contents of the screen of /dev/ttyN can be accessed using the device /dev/vcsN (where `vcs' stands for `virtual console screen'). [...] From a program it is usually better to use /dev/vcsaN (`virtual console screen with attributes') instead - it starts with a header giving the number of rows and columns and the location of the cursor. See vcs(4). }} References
External links
3 : Computer terminals|Terminal multiplexers|User interfaces |
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