Hi,

Bakul wrote:
> (I don’t use vim much to know if it can split windows vertically).

Yes, horizontally or vertically.  Start vim, type `^Ws^Wv' where ^ is
Ctrl, and you'll have three windows.

> I didn’t “move” to vim as it did arbitrary undo/redo incompatibly with
> nvi.

That's still the case.  And it branches the undo history now, e.g. you
undo a few times, then make a new edit, and you old undone edits are
still available, but on another branch; the original one.  Occasionally
useful when you accidentally make an edit that would otherwise wipe the
redo.

Larry wrote:
> > Huh, that's news to me.

    What actually happened was that I was in the process of adding
    multiwindows to vi when we installed our VAX, which would have been
    in December of '78.  We didn't have any backups and the tape drive
    broke.  I continued to work even without being able to do backups.
    And then the source code got scrunched and I didn't have a complete
    listing.  I had almost rewritten all of the display code for
    windows, and that was when I gave up.  After that, I went back to
    the previous version and just documented the code, finished the
    manual and closed it off.  If that scrunch had not happened, vi
    would have multiple windows, and I might have put in some
    programmability—but I don't know
        — https://en.wikipedia.org/wiki/Vi#Distribution

-- 
Cheers, Ralph.
https://plus.google.com/+RalphCorderoy