In message <Pine.A32.3.95.971211142844.84739A-100000@macro.stanford.edu>, you w
rite: 

-> I've had a long-standing problem with pcvt, which I've ignored until now.
-> 
-> Whenever I use vi (and occasionally more), only half the screen gets
-> filled with text. For instance, when I vi a file, the top 16 lines are
-> filled with text. If I type ^L, these 16 lines are re-drawn. If, however,
-> I scroll down the page, the rest of the lines get filled in. Does anyone
-> know why this would be happening?

Check the baud rate [sic] that is assigned to the line in /etc/gettytab.
This happened to me when I upgraded a machine and my /etc/ttys disagreed
with /etc/gettytab.  Hence, it defautled to the a gettytab setting with
speed set to 1200bps.  

vi (and maybe other curses apps) used the low speed as an indicator to
paints things differently, and hence the half-painted screen.

HTH.

--rafal