[Info-vax] VTxxx/VMS term driver: bug or feature?

[Johnny Billquist]

On 2011-06-30 15:28, Bob Koehler wrote:
> In article<iuhlkv$lt4$1 at Iltempo.Update.UU.SE>, Johnny Billquist<bqt at softjar.se>  writes:
>>
>> So a "strange thing" is not a bug?
>
>     What the real terminals do, is something I would consider a bug.

Really? Maybe I'm confused here, or we see different things.

As far as I can tell, the output when you set the terminal to handle 
wrap itself, you get exactly the output that you requested.

With terminal wrap off, and VMS wrap on, VMS is wrapping when it has 
output 80 characters. However, VMS is unaware of the cursor positioning 
effect, so you get wrapping only after outputting 10 characters at the 
right end of the screen. The last character output before wrapping is a 
'0', which is also what is output in column 79, so you see a double '0' 
at the right end of the first line. A real terminal outputs every new 
character at column 80 when no wrapping is in effect.

With xterm (which I tested as an alternative) the terminal obviously 
does not repeat output at column 80, but instead discard excessive 
characters, which is why column 79 and 80 instead show '01'. I'd say 
that is a bug in the emulator, while the real terminal behaves as I 
would expect.

>     That is, the text displayed is not the text I would expect from the
>     documentation that I've read.

I'm unclear what documentation you have read which leads you to that 
conclusion.

>     An emulator should act like the real thing, but I can understand
>     allowing the user to turn on/off bug compatability.

I can buy letting people select if they want VT100 emulation or not. I 
would be fine with that. However, I've yet to see anyone actually 
offering that.

	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