[HECnet] Vt100 tester

[Brian Schenkenberger, VAXman-]

John Wilson <wilson at dbit.com> writes:

I wrote:

- if hidden "wrap" flag is set and in final column and [?7h in effect, <CRLF>
- if in final column, set "wrap" flag for next time (otherwise clear it)
- write character, advancing cursor unless in final column

The plot sickens ... I was starting to feel paranoid and wanted a second
opinion.   So I replaced the UA9636/UA9639 driver/receiver chips in the VT101
that's been kicking around my basement for 10+ years waiting for me to get
around to that.   Now it fails VTTEST too, but not the same way as the VT100!
(Characters only at the margins in the failing test, but with gaps.)   The
132-col tests are all wrong but that's no surprise since the VT101 has no AVO.

Some quick experimentation shows that in the VT101, the rules are the same
as the VT100 ones above as long as the cursor doesn't leave the line where
a char was written to column 80 for the first time.   But if it does (by any
means -- DCA, ESC M, <LF>, ESC [B etc.) then the "wrap" flag is cleared,
whether a printing character is displayed on the other line or not.

OK so DEC's *own* VT100 knockoff isn't even VT100-compatible.   Nap time!

OK.   You've convinced me to dust off my old VT100 and see what/how it does
with these VTTEST test.   I have some other work to address first before my
international travel this week and VMS Bootcamp the week after but, if I'm
able to squeeze out a few precious moments, I'll look into it.
-- 
VAXman- A Bored Certified VMS Kernel Mode Hacker       VAXman(at)TMESIS(dot)ORG

Well I speak to machines with the voice of humanity.