Re: As for vt525: vt220 emulation with ANSI colors for S390

[Dr. Werner Fink]

On 2025/04/03 09:30:45 +0200, Dr. Werner Fink wrote:
> 
> In conmode 3270 the console is used then you can use the x3270 IBM host
> access tool[1] to be able to communicate over the system console of the
> linux kernel.  It supports coloring via ANSI ... beside this you can
> switch into firmware command mode z/VM and back to communicate direct
> with the system console of the linux kernel.
> 
> But in conmode 3215 the console is driven by the firmware of the s390,
> that is you type your command line *local* e.g. in the x3270 or tn3270
> program and then send it to the system console of the linux kernel.
> That is more like a tele line printer where you local type your full
> command line and send it to the remote side.  There is no coloring
> support means the response from the system console of the linux kernel
> is shown raw. This is the reason why here TERM=dumb is prefered.  But
> in x3270/tn3270 you can use and program local input masks but that is
> an other story ;)
> 
> > vt220's never did color.
> > 
> > http://www.bitsavers.org/pdf/dec/terminal/vt220/EK-VT220-TM-001_VT220_Technical_Manual_Nov84.pdf
> > 
> > vt240's had some color support, but was not ANSI (it's part of the ReGIS 
> > feature).
> > 
> > http://www.bitsavers.org/pdf/dec/terminal/vt240/EK-VT240-RM-002_VT240_Programmer_Reference_Manual_Oct84.pdf
> > 
> > ...so there's no reason to invent a "vt220-color" terminal.
> > 
> > If sclp's support for vt220 is limited to matching function-keys and
> > support for ECH, that makes it less likely to be referred to as
> > "vt220-compatible".  You might want to locate some actual documentation
> > for it.  The IBM webpage I pointed to doesn't count as documentation.
> > 
> > For further reading
> > 
> > https://invisible-island.net/ncurses/ncurses.faq.html#vt100_color
> 
> [1] the manual page states:
>     x3270 opens a telnet connection to an IBM host in an X window.
>     It implements RFCs 2355 (TN3270E), 1576 (TN3270) and 1646
>     (LU name selection), and supports IND$FILE file transfer.
>     The window created by x3270 can use its own font for displaying
>     characters, so it is a fairly accurate representation of an
>     IBM 3278 or 3279.  It is similar to tn3270(1) except that it is
>     X-based, not curses-based.


I'd like to note that with qemu s390x on the /dev/ttysclp0 in vt220 mode
the keys F1, upto F5 show (with prefixed Ctrl-V and suffixed space)

  ^[OP ^[OQ ^[OR ^[OS ^[[15~

means differs from new sclp entry here.

  localhost:~ # cat /proc/consoles 
  ttysclp0             -W- (EC p  )    4:65
  ttyS0                -W- (E  p  )
  localhost:~ # tty
  /dev/ttysclp0
  localhost:~ # uname -m
  s390x


On a real LPAR the function keys are not accessible as the HMC web
applet is running in an browser which catch the Ctrl keys as well as
the function keys ... therefore I can not test if this is qemu only.

Beside this in an connected x3270 terminal with conmode=3270 it is
possible to enable e.g. dialog masks (also used for grub2) but as long
as there is no possibilty to move focus like in grub2 masks it is
not usable.

Werner

-- 
  "Having a smoking section in a restaurant is like having
          a peeing section in a swimming pool." -- Edward Burr

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