Null modemNull modem is a communication method to directly connect two DTEs (computer, terminal, printer, etc.) using an RS-232 serial cable. The name stems from the historical use of RS-232 cables to connect two teleprinter devices or two modems in order to communicate with one another; null modem communication refers to using a crossed-over RS-232 cable to connect the teleprinters directly to one another without the modems. It is also used to serially connect a computer to a printer, since both are DTE, and is known as a Printer Cable.
TermcapTermcap (terminal capability) is a software library and database used on Unix-like computers. It enables programs to use display computer terminals in a device-independent manner, which greatly simplifies the process of writing portable text mode applications. Bill Joy wrote the first termcap library in 1978 for the Berkeley Unix operating system; it has since been ported to most Unix and Unix-like environments, even OS-9. Joy's design was reportedly influenced by the design of the terminal data store in the earlier Incompatible Timesharing System.
Xtermxterm is the standard terminal emulator for the X Window System. It allows users to run programs which require a command-line interface. If no particular program is specified, xterm runs the user's shell. An X display can show one or more user's xterm windows output at the same time. Each xterm window is a separate process, but all share the same keyboard, taking turns as each xterm process acquires focus. Normally focus switches between X applications as the user moves the pointer (e.g.
End systemIn networking jargon, a computer, phone, or internet of things device connected to a computer network is sometimes referred to as an end system or end station, because it sits at the edge of the network. The end user directly interacts with an end system that provides information or services. End systems that are connected to the Internet are also referred to as internet hosts; this is because they host (run) internet applications such as a web browser or an email retrieval program.
IoctlIn computing, ioctl (an abbreviation of input/output control) is a system call for device-specific input/output operations and other operations which cannot be expressed by regular system calls. It takes a parameter specifying a request code; the effect of a call depends completely on the request code. Request codes are often device-specific. For instance, a CD-ROM device driver which can instruct a physical device to eject a disc would provide an ioctl request code to do so.
Null characterThe null character (also null terminator) is a control character with the value zero. It is present in many character sets, including those defined by the Baudot and ITA2 codes, ISO/IEC 646 (or ASCII), the C0 control code, the Universal Coded Character Set (or Unicode), and EBCDIC. It is available in nearly all mainstream programming languages. It is often abbreviated as NUL (or NULL, though in some contexts that term is used for the null pointer). In 8-bit codes, it is known as a null byte.
History of display technologyElectrically operated display devices have developed from electromechanical systems for display of text, up to all-electronic devices capable of full-motion 3D color graphic displays. Electromagnetic devices, using a solenoid coil to control a visible flag or flap, were the earliest type, and were used for text displays such as stock market prices and arrival/departure display times. The cathode ray tube was the workhorse of text and video display technology for several decades until being displaced by plasma, liquid crystal (LCD), and solid-state devices such as thin-film transistors (TFTs), LEDs and OLEDs.
Datapoint 3300The DataPoint 3300 was the first computer terminal manufactured by Computer Terminal Corporation, later renamed Datapoint, announced in 1967 and shipping in 1969. Since this terminal was intended to replace a teleprinter such as those made by Teletype Corporation it was one of the first glass TTYs (glass for the screen, TTY as the abbreviation for "Teletype") ever produced. As well as being sold under its own name, it was also sold as the DEC VT06 and the HP 2600A (introduced in 1972).
Menu (computing)In user interface design, a menu is a list of options or commands presented to the user of a computer or embedded system. A menu may either be a system's entire user interface, or only part of a more complex one. Human–computer interaction A user chooses an option from a menu by using an input device. Some input methods require linear navigation: the user must move a cursor or otherwise pass from one menu item to another until reaching the selection. On a computer terminal, a reverse video bar may serve as the cursor.
Terminal (telecommunication)In the context of telecommunications, a terminal is a device which ends a telecommunications link and is the point at which a signal enters or leaves a network. Examples of terminal equipment include telephones, fax machines, computer terminals, printers and workstations. An end instrument is a piece of equipment connected to the wires at the end of a telecommunications link. In telephony, this is usually a telephone connected to a local loop.