Origin of hosts, consoles, and terminals in Linux

Origin of hosts, consoles, and terminals in Linux
GuideIf you have seen some desktops, most of them are like this. The keyboard, display, and chassis can be separated. Even if the chassis and the user are not in the same room, the computer can still be used as long as the line is connected. In the early days, the chassis was indeed separated from the keyboard and display.Do you know the origins of hosts, consoles, and terminals in Linux?

At the beginning of UNIX, computers were very expensive. At that time, there was no personal computer. Most computers were large, expensive, and unstable machines and must be stored in a humidity and temperature controlled environment. Bell Labs's Thompson began looking for small and cheap computers. At that time, most computers needed $100,000. In 1970 he and his colleagues got a PDP-11 and needed $10,800. Within a few months, they migrated UNIX to the computer. But PDP-11 can run only one program at a time, so they modified the UNIX system so that it could run multiple programs at a time until 1973 that goal was achieved.

From this we can see that there are a lot of buttons on the PDP-11 body, this operation panel is called the console. The console is closely integrated with the host and cannot be remotely operated. Many operations need to be done through the console (for example, problems encountered during the Startup Process), because the terminal can be connected only when the host is started and the network connection is normal. Since large computers are expensive, Thompson and his colleagues want UNIX to be called a multi-tasking (that is, running multiple programs at the same time), a multi-user system. In that age, computers had no independent keyboards, and they were not allowed to have a single computer because of their expensive prices.

Thompson decided to use a cheap telex typewriter: Teletype. Till now, the text input and output environments in Linux and UNIX systems are abbreviated as tty (TeleTYpe ). Teletype is quite primitive. Everything except power supply is mechanical.

Let's imagine that if many users each have their own Teletype and the "data center" (called the "glass house" at the time ", because at the time many companies used glass walls to show expensive large computers, there was an expensive large computer PDP-11 running UNIX that could be accessed by multiple users, each user can access a large computer by using Teletype, which is equivalent to having a computer at a low price. Yes. At that time, Thompson thought so and finally implemented it. This idea has a large number of applications, such as the relationship between servers and terminals.

A large computer PDP-11 is called a host, and a user's Teletype is also called a terminal (originally the end of a wire ). Because the host and terminal are separated, both host replacement and terminal replacement are independent of each other. The host and terminal can continue to develop with the wave of technology. Roughly speaking: Computer = Host + Terminal; terminal = input device + output device. In this example, computer = PDP-11 + telex typewriter; Teletype = input device (keyboard) + output device (paper ).

If multiple hosts are stored in the data center and multiple terminals use these hosts, how can they be connected? This requires the terminal server. The terminal server connects the host and the terminal. You only need to enter the host to be accessed, and the terminal server will establish a connection between them. For example.

These are the origins of hosts, consoles, and terminals in Linux.

Question: Ken Thompson (SIT), Dennis Ritchie (Station) with PDP-11 and Teletype 33-ASR, the source is not available.

Address: http://www.linuxprobe.com/terminal-linux-shell.html