Two Weird Problems

Craig Johnson vince at tc.fluke.COM
Thu May 25 05:59:23 AEST 1989


> From: jimmy at denwa.uucp (Jim Gottlieb)
> Message-ID: <295 at denwa.uucp>
> 
> Second problem:  In the last month or so I have started having problems
> using vi over dial-up.  I use cu to dial into a few different systems,
> and when I move the cursor to the right, several characters on my
> screen get erased and I have to ^L to redraw the screen.  Again, this
> problem just started happening recently.  The termcap entries on the
> BSD systems I dial into have not been changed.  Again, I'm baffled.

I'm very familiar with this problem!  I frequently use a login on a
vt100 on tty000 to call out to a remote BSD system.  The problem is the
BSD system and the 3B1 have different default stty settings for tabs.
The BSD system thinks tab characters are OK to use and the 3B1 thinks
tabs should be expanded to spaces.  When vi is run on the remote
system, curses trys to optimize cursor positioning by issuing tabs when
appropriate.  Unfortunately, when the 3B1 expands tabs, spaces
overwrite characters on the screen.  To compound things, on the vt100
the 3B1 doesn't really know where the cursor is due to curses' direct
cursor addressing, and may end up expanding to the wrong number of
spaces.

The solution is to setup tab expansion (with stty) to be the same on
both the local and remote systems.  I execute "stty tabs" prior to
invoking cu.

I don't recall seeing this problem from the console, but I assume that
tabs expanded into spaces would at least have the same problem of over-
writing characters on the screen.


	Craig V. Johnson		...!fluke!vince
	John Fluke Mfg. Co
	Everett, WA



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