I just printed a very long graphics-heavy document to my DECcolorwriter, and
after 25 pages or so, something started dropping characters.  I don't know
if it's the driver doing something wrong and overrunning the print buffer
(though the code looks right) or if it's the printer not issuing BUSY signals
correctly.  (I may try to build a breakout box and primitive logic analyzer
to see if the handshaking is correct.)

I am using the interrupt-less driver, by the way (device number 192, which
is also the no-reset-on-open device; I was rather pissed to discover that of
a long series of lpr requests issued in rapid succession, I successfully
printed 1 and a half...).