27 Feb
2013
27 Feb
'13
4:30 p.m.
On 02/27/2013 09:33 AM, Diane Bruce wrote:
On Wed, Feb 27, 2013 at 12:37:19PM +0100, MG wrote:
One way to seriously slow the terminal down was to enable smooth scroll
as that took a fair amount of cpu cycles to implement.
The fastest was jump scroll and set to VT52 mode. Data setups with
8bits and stick parity with 2 stop bits were better than 7bits. reason
that added two bit times per character (slows the overall character rate).
When the host is DEC and local (less than 50ft cable) I used to run
19.2k on my Vt102 (smooth scroll and Vt100 mode, xon/off) and it
was great when editing.
On 27-feb-2013 2:35, Diane Bruce wrote:
*laugh* The important thing here is to solve
the problem, not worry
about age differences. ;) I do have a copy of a VT-100 manual downstairs
somewhere, and I do recall it stating number of nuls per baud rate to insert
or suggesting the use of flow control. I am sure a copy of the manual is
online if anyone is really curious.
I do remember being very disapointed at the time I first read this
some time (*cough*) ago, as the framebuffers of a modern PC were still
a few years away. We all treasured serial speed, as that was the way
things were done. Having a terminal claiming it could run 9.6K was nice
but disapointing it could not actually keep up. The VT100 could not keep up with full speed 9600
baud. The back of
the VT100 manual has a table of how many nul chars you need per baud rate.
Well, I
have never owned or used a (real) PDP-series system. (I was
also born long after their heyday.) Heh the wikipedia article shows it was running an
8080
http://en.wikipedia.org/wiki/DEC_VT102
I owned one working Volker-Craig terminal and several more parts ones.
http://vt100.net/volker-craig/
I gave them all to a member of this list.
It seemed to run a tad faster than the real VT100. I seem to recall
spotting a Z-80 on that board.
The H19 used a Z80. The vt100 was top of the line
for its time to be
replaced with the VT220. In the between there were varients like the 102
that were actually a little better.
Oddly enough there were a lot of oddities of the Vt100 that didn't make it
to many of the look alikes. Some even broke VT100 emulation enough
to not work at all right for some of the more extreme tests.
Generally if there is trash on the screen slow down, 2400 is usually enough.
Allison