Actually, the stock terminal driver in V6 Unix (here: http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/sys/dmr/tty.c if anyone wants to see the actual code; it's in ttyoutput()) had some pretty complex code to do just the right amount of delay (in clock ticks) for a large number of different motion contral characters (TAB, etc, in addition to LF and CR), and then uses the system timer to delay that amount of real time after sending such a character (see the very bottom of ttstart()). E.g. for a NL, it used the fact that it 'knew' which column the print head was in to calculate the exact return time. Clever, but alas, it did this by sticking 'characters' in the buffered output stream with the high bit set, and the delay required in the low 0177 bits, which the output start routine interpreted; as the code drolly notes, "thus (unfortunately) restricting the transmission path to 7 bits". Which was a real PITA recently when I tried to download a binary file to an LSI-11 from a V6 running in Ersatz-11! I had to tweak the TTY driver to allow 8-bit output... Noel