[Info-vax] Last Call for (New) DEC VT Terminals

[Johnny Billquist]

On 2015-06-28 01:30, Simon Clubley wrote:
> On 2015-06-27, Jan-Erik Soderholm <jan-erik.soderholm at telia.com> wrote:
>> Scott Dorsey skrev den 2015-06-27 20:00:
>>
>>>
>>> How important is good emulation to you?  Is emulating the vt100 line 25
>>> bug important?  For me, it's not.  For others it might be.
>>> --scott
>>>
>
> I'm only interested in emulating the published specifications (unless
> DEC used undocumented VT bugs when writing it's software).
>
>>
>> There are some rumors about lack of compatibility around.
>> Someone hade a script that tested DW/DH "problems". Worked
>> just fine in both Reflection and PyTTY when I tested...
>> I have not seen any compatibility issues that have been
>> real show-stoppers. No compatibilty issues at all, actualy.
>>
>
> The main PuTTY bug for me is a keyboard emulation bug.
>
> Unless the keyboard emulation is the strict VT layout keyboard
> (where the key functions are mapped to their position on the keyboard
> and not to the function as labelled on the PC keyboard) then PF1-PF4
> doesn't work unless application keypad mode is active.
>
> As most of the DEC software which uses PF1-PF4 first puts the keypad
> into application keypad mode, you don't usually notice this, but for
> software which doesn't do this, it's a compatibility issue.

For me, the most annoying PuTTY bug is how it behaves when writing and 
backspacing at column 80. If you write at column 80 without automatic 
wrapping, the character appears at column 80, and the cursor remains at 
column 80. If you then backspace on a real VT100, your cursor will move 
back to column 79. In PuTTY, the cursor remains at column 80, because 
the PuTTY developers prefer this behavior, even though it is 
incompatible. I talked with them many years ago about this, but they 
refused to change their code. So I have a program that I've written, 
which behaves correctly on a real terminal, but will exhibit a broken 
behavior in PuTTY.
Other than that, PuTTY nowadays is pretty good, but that is (partly) 
because I went over it many years ago and talked with the developers and 
got them to fix a lot of errors, There are a whole bunch of really 
typical errors in emulation that almost all emulations get wrong, even 
though the behavior is documented.
I have a few programs that I always test with when I try a new 
emulation, and they almost always fails pretty fast.

Keyboard emulation bugs are also annoying by the way, but I've never 
tried finding those. Thanks for the info on PuTTY there. Worth noting 
that the PF keys send different codes if they are in keypad mode or not. 
As do the arrow keys...

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol