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From: guy@sun.uucp (Guy Harris)
Newsgroups: net.unix-wizards,net.info-terms
Subject: Re: tset vt100 destroys scrolling on SUN-2/120
Message-ID: <2938@sun.uucp>
Date: Sat, 26-Oct-85 19:31:15 EST
Article-I.D.: sun.2938
Posted: Sat Oct 26 19:31:15 1985
Date-Received: Mon, 28-Oct-85 04:18:14 EST
References: <221@gargoyle.UUCP> <1159@sdcsvax.UUCP>
Followup-To: net.info-terms
Distribution: net
Organization: Sun Microsystems, Inc.
Lines: 29
Xref: watmath net.unix-wizards:15479 net.info-terms:689

> >We have discovered that accidentally doing a "tset vt100" from
> >our SUN consoles screws up their scrolling (and vi, and more, and....)
> >The problem is due to the initialization string sent to the
> >console (ESC[1;24r)....
> 
> In the list of commands that the SUN terminal emulator groks is a note
> that the sequence  will reset the terminal to a sort of virgin
> state.  Especially useful is that it undoes the set-scrolling-area
> limit of 24 lines that your vt-100 tset did.

The SUN console/terminal emulator don't interpret [N;Mr as a
VT100-style "set scrolling region" command - that escape sequence is in the
series reserved by X3.64 for private escape sequences, and "set scrolling
region" is DEC-private.  The escape sequences are documented in the Sun UNIX
2.0 manual page CONS(4S), where it also says

	The Sun terminal emulator and the VT100 are *not* compatible
	in any true sense.  (Italics in the original).

[Nr is "set scrolling" (SUNSCRL), which takes one parameter, default 0.
It "sets to N an internal register which determines how many lines the
screen scrolls up when a line-feed function is performed with the cursor on
the bottom line".  An N of 1 is the normal mode; N of the screen size causes
the screen to clear instead of scrolling; N of some small value >1 causes
the screen to jump a bit when scrolling.  N of 0 causes the console, but not
the SunWindows terminal emulator, to move the cursor to the top line without
scrolling; the top line is cleared, but the screen is otherwise unchanged.

	Guy Harris