vt100 terminfo with padding for an actual vt100?

Warner Losh imp at bsdimp.com
Mon Sep 5 11:05:55 CDT 2016

The usual answer, from back in the day, was to make sure hardware flow
control was on and working at higher speeds. If you don't have that,
you are going to lose > 9600 baud. I spent way too much time pulling
fat cable to enable this after we'd wired the building with 3-wire
cable for the VT52's and cute 'headphone' plug-in jacks back in my
high school days...


On Mon, Sep 5, 2016 at 1:24 AM, Adrian Graham
<witchy at binarydinosaurs.co.uk> wrote:
> On 05/09/2016 01:10, "Fritz Mueller" <fritzm at fritzm.org> wrote:
>> Hi all ‹
>> I¹m trying to run a real-deal vt100 on a serial port connected to Linux
>> (Xubunto 16.04).  I¹ve got this working *pretty* well, but it looks like the
>> padding values in the default vt100 terminfo entry are not quite correct ‹
>> when running the vt100 at 9600 I still get occasional garbage characters on
>> the screen, and 19200 is a hopeless mess.
>> I did figure out that if the terminfo contains ³xon², the non-mandatory
>> padding values in the terminfo are disregarded.  Removing this, then disabling
>> xon/xoff on both the vt100 and the tty device actually produces *better*
>> results ‹ apparently the turnaround on xon/xoff isn¹t quite fast enough to
>> keep the terminal from being swamped at higher baud rates, and padding
>> actually works better.  But tracking down the source for the default vt100
>> entry turned up a comment that admits that the padding values there are a
>> total guess. :-(
>> So, before I go diving too much further into the terminfo-tweaking-samp, I
>> thought I¹d ask if anybody has a good vt100 entry already on hand?  (I¹d take
>> one for the VT52 as well!)
> Interesting. I'm running a genuine VT100 from a home-made serial port
> (MAX3232 based) on a Beaglebone Black running Debian Jessie as part of my
> DECbox project and it's rock solid at 9600 baud, even with smooth scroll.
> I'd never given the termcap entry a moment's thought.
> This may or may not help, but when talking serially to a ZX Spectrum (I
> know, but it's still RS232 comms) I get consistent results with a genuine
> serial port on a laptop but with a cheap chinese USB-serial converter it
> just doesn't work and I put this down to incorrect grounding.
> --
> Adrian/Witchy
> Binary Dinosaurs creator/curator
> Www.binarydinosaurs.co.uk - the UK's biggest private home computer
> collection?

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