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Thread: Terminal Questions

  1. #1
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    Default Terminal Questions

    Ok, not to muck things up for everyone having such a nice IBM discussion but I have a terminal question too! I know how ANSI is implemented on a terminal and understand the advantages of using it but I was wondering just how it was used on the system end? The reason I ask is that I have a couple old military terminals that I wanted to build up a project with but they are hardwired for ANSI operations only. So far I have thought of just using something like a PDP-11 or better yet my Rolm NOVA (copy of a Data General NOVA) and writing up some machine language stuff and pushing that thru a port and just finding out what the movement commands would be and incorporating them just like character data the question is can someone point me to a place where I can find out how to map screen locations and ANSI command syntax? How was ANSI used back in the day or did the programmers of old just do the same thing?

  2. #2
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    Unix much? See "curses" for how different terminal protocols were managed. ANSI and VT100 are very close in major functions.

  3. #3
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    Which ANSI terminal standard are you planning on using? The one I am familiar with was basically the same as the DEC VT100 so should be easy to work with a PDP-11.

  4. #4
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    ANSI is (Almost) formal specification of VT100/VT102. It uses (mostly) escape sequences to direct the cursor.

    https://en.wikipedia.org/wiki/ANSI_e...cape_sequences

    on UNIX programs that want to do full screen control take the codes from either TERMCAP (old) or TERMINFO(new) either directly or more usually via a library such as CURSES.

    http://www.tldp.org/HOWTO/Text-Terminal-HOWTO-16.html

    in fact this site appears to have all the info you will need:-

    http://www.tldp.org/HOWTO/Text-Termi...WTO.html#toc16

    but basically you can plug the terminal into a serial port on a UNIX box and if configured properly, it will work just like a TELNET session. There is an environment variable that defines the terminal type and which is used by programs to work out which escape sequences to send. This means the that when in full screen mode each character is passed back to the application. On older systems where they were memory constrained this could lead to heavy paging.

    You can also get terminal servers, these have an Ethernet Port and Serial ports and generally allow you to telnet from a dump terminal to any system that supports telnet...

    .. I guess these days you could use an ESP8266 board with RS232 level converters...
    Dave
    G4UGM

    Looking for Analog Computers, Drum Plotters, and Graphics Terminals

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