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From: blarson@skat.usc.edu (Bob Larson)
Newsgroups: comp.terminals
Subject: Re: Mysterious VT100 behaviors
Keywords: vt100 undocumented behavior information wanted
Message-ID: <11989@oberon.USC.EDU>
Date: 5 Sep 88 04:53:20 GMT
References: <13801@agate.BERKELEY.EDU> <6249@dasys1.UUCP>
Sender: news@oberon.USC.EDU
Reply-To: blarson@skat.usc.edu (Bob Larson)
Organization: USC AIS, Los Angeles
Lines: 29

In article <6249@dasys1.UUCP> pechter@dasys1.UUCP (Bill Pechter) writes:
>There'a a number of undocumented "features" on the VT100 - some of which
>are real nasty microcode bugs in the firmware.

My favorites:

Infinite wait mode (display wait in the upper left corner until someone
hits the power switch): <esc>[?2;8y

Flashing background mode (also puts the terminal in local):
<esc>[?2;15y (I think)

Disabling flow control and sending scrolling region sequences at 2400
baud would drive the vt100 batty, sometimes doing such things as 24
copies of one line (the one with the cursor, the terminal still works!)
reverse scroling (linefeed means go up a line) etc.  Usually the terminal
would reset itself eventually.

(If you didn't guess, the policy of not letting students read the manual
wasn't very efective, it led us to things we wouldn't have found otherwise.)

Some of the documented sequences were fun too: Tops-10 had a way to
type a file (in a public directory) from a not logged in terminal.
By putting a ^E in the end of the file and programming the answerback
buffer, an infinite loop displaying the file could be created.
Bob Larson	Arpa: Blarson@Ecla.Usc.Edu	blarson@skat.usc.edu
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