Text-Terminal-HOWTO: Introduction

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## 1. Introduction

For a quick attempt to install a terminal see Quick Install.

## 1.1 Copyright, Trademarks, Disclaimer, & Credits

### Copyright

Copyright 1998-2010 by David S. Lawyer. mailto:dave@lafn.org

Please freely copy and distribute (sell or give away) this document in any format. Send any corrections and comments to the document maintainer. You may create a derivative work and distribute it provided that you:

1. If it's not a translation: Email a copy of your derivative work (in a format LDP accepts) to the author(s) and maintainer (could be the same person). If you don't get a response then email the LDP (Linux Documentation Project): submit@en.tldp.org.
2. License the derivative work in the spirit of this license or use GPL. Include a copyright notice and at least a pointer to the license used.
3. Give due credit to previous authors and major contributors.

If you're considering making a derived work other than a translation, it's requested that you discuss your plans with the current maintainer.

### Disclaimer

While I haven't intentionally tried to mislead you, there are likely a number of errors in this document. Please let me know about them. Since this is free documentation, it should be obvious that I cannot be held legally responsible for any errors.

### Trademarks.

Any brand names (starts with a capital letter such as MS Windows) should be assumed to be a trademark). Such trademarks belong to their respective owners.

### Credits

Greg Hankin's Serial-HOWTO v.1.11 (1997) section "How Do I Set Up A Terminal Connected To My PC?" was incorporated into v1.00 at various places (with Greg's permission). v1.09 of Text-Terminal-HOWTO had about 25 changes (and error corrections) suggested by Alessandro Rubini. For v1.26 I fixed about 25 typos, etc. found by Alain Cochard. Jeremy Spykerman told me about using a keyboardless terminal as a console for a monitorless PC (using ttysnoop). Numerous other people have made a suggestion or two or found a few typos. Thanks.

## 1.2 Future Plans: You Can Help

Real text terminals are pretty much obsolete except for legacy applications, but GUI terminals (variously known as thin clients, ultra-thin clients, and zero-clients) are claimed to be the wave of the future. What is needed today is for someone to start with the brief overview of GUI terminals in this HOWTO and create a new and up-to-date HOWTO on thin clients.

Please let me know of any errors in facts, opinions, logic, spelling, grammar, clarity, links, etc. But first, if the date is over a couple of years old, check to see that you have the latest version. Please send me any info that you think belongs in this document.

In order to fully utilize all the features of a certain real terminal, one needs the terminal manuals that came with the terminal when it was new. If you don't have a manual, this HOWTO may be of some help. One way to have solved this problem would be for terminal manufacturers put their manuals on the Internet but they never did.

## 1.3 New Versions of this HOWTO

New versions of the Text-Terminal-HOWTO should be released every couple of years. To get the latest version go to an LDP mirror sites (see: http://www.tldp.org/mirrors.html). To quickly check the date of the latest version look at Text-Terminal-HOWTO.html. The version your are currently reading is: v1.42 January 2010 .

For a full revision history going back to the first version in 1998 see the source file (in linuxdoc format): (cvs) Text-Terminal-HOWTO.sgml

- v1.42 Jan. 2010 PuTTY serial terminal emulator, cutecom (dumb emulator), colors, links to wikipedia, Boundless still selling terminals, small footprint terminals, link to art. on text browsers.
- v1.41 Feb. 2008" Better clarity re emulation. Illusion when revere-video is reversed. Problem with slow scrolling. Wyse text terminals discontinued and Boundless was bankrupt. Update on text web browsers. gtkterm, X Window now has many terminal emulators. Symantec no longer selling Procomm.
- v1.40 Dec. 2006 Picocom is like minicom. Devfs obsolete so removed tts/1, etc. Updated pseudo terminals. More about telnet, ssh, and non-serial port interfaces. IBM terminal emulation over telnet. Kermit for MS does terminal emulation. Ports of minicom to Mac. Fixed/removed broken links. "reset" is an alias for "tset"

## 1.4 Related HOWTOs, etc.

Go to the nearest mirror site (per above) to get HOWTOs.

- Serial-HOWTO has info on Multiport Serial Cards used for both terminals and banks of modems. It has general technical info on the serial port including troubleshooting it.
- Low-Level Terminal Interface part of "GNU C Library Reference Manual" (in libc (or glibc) docs package). It covers the detailed meaning of "stty" commands, etc.
- NCURSES-Programming-HOWTO
- MacTerminal mini-HOWTO
- Modem-HOWTO
- Serial-Programming-HOWTO
- NC mini-HOWTO
- NCD-X-Terminal mini-HOWTO
- XDM-and-X-Terminal mini-HOWTO
- Connecting-X-Terminals-to-Linux-Mini-HOWTO
- NCD-HOWTO
- Thinclient-HOWTO
- Xterminals-HOWTO
- Xterm-Title-HOWTO (only for changing the title of a window)

## 1.5 Terminology Used in this Document

Configuration means the same as set-up. While Linux commands take options (using - or -- symbols), options in a broader sense include various other types of choices. Install in the broad sense includes setting up (configuring) software and hardware. A statement that I suspect is true (but may not be) ends with 2 question marks: ?? If you know for sure, let me know.

## 1.6 What is a Terminal ?

A terminal consists of a screen and keyboard that one uses to communicate remotely with a computer (the host). One uses it almost like it was a personal computer but the terminal is remote from its host computer that it communicates with (on the other side of the room or even on the other side of the world). Programs execute on the host computer but the results display on the terminal screen. Originally terminals were stand-alone devices with no computational ability and thus they were once much cheaper in cost than computers. They had no pictures or audio, but could only display text and were thus called "text terminals". Today, the cost of PC computers is so low that one may use a PC like a text terminal by running a software program to make it behave like an old text terminal. You formerly found real text terminals at libraries and schools.

## 1.7 Real Text Terminals

In the olden days of mainframes, from the mid 1970's to the mid 1980's, most communication with large computers was done by people sitting in front of real text-terminals. And in the 1970's, before the advent of personal computers, it was the only way to interactively communicate with any computer. These real text-terminals were neither computers nor emulated text-terminals. They consisted only of a screen, keyboard, and only enough memory to store a screenfull or so of text (a few kilobytes). Users typed in programs, ran programs, wrote documents, issued printing commands, etc. A cable connected the terminal to the computer (often indirectly). It was called a terminal since it was located at the terminal end of this cable. Some text-terminals were called "graphic" but the resolution was poor, the speed slow, and little software was available to support such graphics.

Today, real terminals are becoming rarities for most all computer users. But there is still some specialized uses for them as point-of-sale devices and for access to mainframes and servers where graphics and pictures are not needed. However, if a text terminal is needed people will sometimes use a personal computer to emulate a terminal.

Almost everyone who uses Linux also uses terminal emulation. When you are not using an X Window GUI at a Linux PC, you are likely using a text interface (virtual terminal). It's also called a "command line interface". In X Window one can also get a command line interface using one or more terminal windows by using an x-terminal-emulator with names such as xterm, gnome-terminal, or konsole (KDE). All these use software to emulate a real terminal. However in these cases, one doesn't need most of the information provided by this HOWTO since such emulation is automatically set up for the user. However if one emulates a terminal using a software program and then connects that emulated terminal to another computer via a serial port cable, then this HOWTO should be more useful (provided your PC has a serial port on it --almost all recent PCs made after 2009 didn't have them anymore).

A real text-terminal is different from a monitor or x-terminal-emulator because the simple character images that get displayed on the text-terminal are stored right inside the terminal in it's memory. For a monitor or x-terminal-emulator, the images are stored in the video card of the PC and/or in the PC's memory itself. The text-terminal's keyboard plugs into the the terminal and is part of the terminal while a PC's keyboard plugs into the computer.

For a monitor, the video images are sent by a short cable running from the video card to the monitor while for a text-terminal there is a bi-directional flow of character bytes in a long cable between the computer's serial port and the PC it's connected to. Most text terminals do not have mice.

In network client-server terminology, one might think that a real terminal is the client and that the host computer is the server. The terminal has been called a "thin client" by some. But it is not actually a "client" nor is the host a "server". The only "service" the host provides is to receive every letter typed at the keyboard and react to this just like a computer would if you typed at its own keyboard. The terminal is like a "window" into the computer just like a monitor (and keyboard) are. You may have already used virtual terminals in Linux (by pressing Left Alt-F2, etc.). A real terminal is just like running such a virtual terminal but you run it on its own terminal screen instead of having to share the monitor screen. In contrast to using a virtual terminal at the console (monitor), this allows another person to sit at another real terminal and use the same computer simultaneously with others. Such multi-user interfaces are not "clients" and a server..

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