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Thread: VT52 vs VT100: differences?

  1. #1

    Default VT52 vs VT100: differences?

    I am going to develop my own VT-term, but I need to understand
    1) how much simpler VT52 goes, concerning the finite state machines, transactional events, protocol implementation, etc
    2) if VT52 can operate with Linux, "export TERM=vt52" doesn't seem good at the moment with nano
    3) which is the minimal working specs

    Is there any full article about this?

  2. #2
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    VT52 is much simpler that ANSI/VT100. VT100's will work in VT52 mode.

    http://ascii-table.com/ansi-escape-sequences-vt-100.php

    the VT52 codes are at the bottom
    Dave
    G4UGM

    Looking for Analog Computers, Drum Plotters, and Graphics Terminals

  3. #3
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    Quote Originally Posted by ivelegacy View Post
    I am going to develop my own VT-term, but I need to understand
    1) how much simpler VT52 goes, concerning the finite state machines, transactional events, protocol implementation, etc
    2) if VT52 can operate with Linux, "export TERM=vt52" doesn't seem good at the moment with nano
    3) which is the minimal working specs

    Is there any full article about this?
    What do you mean by ""export TERM=vt52" doesn't seem good at the moment with nano"?

    There are big differences between a VT100 and a VT52. The VT52 have much less functionality, and the format of the escape sequences to control it are in a less flexible form, but easier to process.

  4. #4

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    Quote Originally Posted by bqt View Post
    doesn't seem good at the moment with nano"?
    "Export TERM=v52" sets the variable TERM in the environment, but it looks no-good. It seems the standard text terminal emulation on Linux does not emulate a VT52. Nano (it's a text editor) goes nut.

    The X11 terminal seems able to simulate a VT52, you need to tell your environment that you run a VT52.

    Code:
    xterm -ti vt52 -tn vt52
    Xterm itself is a VTxxx emulator the "xterm" protocol is a superset of VT102/VT220 in the first place, with some features from VT320/VT420/VT520, and of course some entirely new to Xterm itself.

    Quote Originally Posted by bqt View Post
    There are big differences between a VT100 and a VT52. The VT52 have much less functionality, and the format of the escape sequences to control it are in a less flexible form, but easier to process.
    That sounds better if you want to synthesize a simpler finite state machine, but ... this way I will probably need to hack the standard Linux text terminal in order to add the VT52 support.

  5. #5

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    I'm confused. I'm on a fairly modern Linux system here that "infocmp vt52" shows me that vt52 is a supported terminal type.

    What exactly needs hacking?

  6. #6

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    Quote Originally Posted by mbbrutman View Post
    infocmp vt52" shows me that vt52
    here it seems supported only by xterm (x11 terminal); the user can configure xterm to respond to VT220-specific control sequences, and it will identify itself as a VT52, VT100, and up depending on the way it is configured and initialized.

    without x11, you have the Linux console, a system console internal to the Linux kernel. The Linux console provides a way for the kernel and other processes to send text output to the user and to receive text input from the user. The user typically enters text with a computer keyboard and reads the output text on a computer monitor via a console on a framebuffer (fb-con) driver. The Linux kernel supports virtual consoles - consoles that are logically separate, but which access the same physical keyboard and display. The one I can use is based on the "fbcon-driver" and its infrastructure is presented to the user as a series of virtual consoles. These give the impression that several independent terminals are running concurrently; each virtual console can be logged in with different users, run its own shell and have its own font settings. The virtual consoles each use a device /dev/tty{1,2,3,4,...}, and you can switch between them by pressing Alt+Fx (where x is equal to the virtual console number, beginning with 1). The device /dev/console is automatically mapped to the active virtual console.

    This stuff seems to not support vt52, but it does support vt100 and vt220. It's not still clear where/what I have to hack, but probably implementing a vt52 with all these complications is not worth with.
    Last edited by ivelegacy; January 30th, 2020 at 11:02 AM.

  7. #7

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    Perhaps a stupid questio, but ... what's the VT100 escape code for the "esc" keyboard key itself?!?

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    Quote Originally Posted by ivelegacy View Post
    Perhaps a stupid questio, but ... what's the VT100 escape code for the "esc" keyboard key itself?!?
    There is none. The ESC key sends just an ESC.
    Which means you can "fake" the uparrow key by pressing ESC [ A, for example. Although you'll probably be off on the timing. And of course, if you enable application keys, the uparrow will send a different sequence (ESC O A).

  9. #9
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    Quote Originally Posted by ivelegacy View Post
    "Export TERM=v52" sets the variable TERM in the environment, but it looks no-good. It seems the standard text terminal emulation on Linux does not emulate a VT52. Nano (it's a text editor) goes nut.
    Of course not. Because nano will then try to control your terminal as if it were a VT52. But your terminal don't suddenly become a VT52 because of this.

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    I'm confused--and I've implemented both VT52 and VT100 firmware in terminals. VT100 is much more involved. You could probably code a VT52 protocol in a day. Not so much for ANSI/VT100.

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