1st character change in file takes forever

[David Klein <dklein@bloombergREMOVETHISPART.com>]

When I first try to insert a character into a buffer that is
associated with a file on disk, the insert takes close to a minute!

Before attempting the insert I can do whatever I want, e.g. split the
window, change to the *scratch* buffer and insert text there. Response
is instantaneous. After getting passed the first character, everything
works fine, even if I try to insert a character into a new file.

The behaviour remains even when I start emacs with 

emacs -q --no-site-file

or even

emacs -q --no-site-file

I have tried this under GNU Emacs 20.3.1 (I also tried it switching
the "emacs" executable to GNU Emacs 20.3.1).

My OS is

Linux sleepy 2.2.5-15 #1 Mon Apr 19 23:00:46 EDT 1999 i686 unknown

Any ideas how I can try to track this down? I tried 
(debug-on-entry 'self-insert-command)

but emacs tells me that it is a primitive (surprise, surprise).

-- 
Use of tools distinguishes Man from Beast. And UNIX users from WINDOZE lusers.