Date   : Tue, 16 Jun 2009 11:08:35 +0100
From   : robert@... (Rob)
Subject: Teletext / Viewdata / Prestel people

On 16/06/2009, Joel Rowbottom <joel@...> wrote:

>>
>> Sort of - Prestel wrote a special version of their gateway interface
>> that tanslated the scrolling format into viewdata - basically, when
>> you reached the bottom of the screen, it carried on from the top.
>
> That was common to the Viewdata spec though.

Well, yes and no.  Viewdata terminals had no scrolling - go down on
line 24 and you arrive on line 1 again and start overwriting any text
there.  Log into a standard 'scrolling' BBS on a viewdata terminal and
you swiftly get a mess when new text leaves old stuff behind..

What the gateway did was sanitise that output, so it wiped the line
next to be overwritten beforehand, and avoided using line 24 itself,
as this was used for * command inputs.  I think it actually ran the
game output in an even smaller wndow, taking user commands in a box in
lines 22-23 or so.  I'm a bit vague as, although I was at Micronet
while it was being implemented, I didn't have anything to do with it,
and barely used it once it was released - I think there was a charge,
and  avoided anything chargeable, preferring to just dial into real
MUDs when I wanted to...

Rob