TANDEM mode bugs in 4.3bsd

[Roy Smith]

In <2439 at sdcsvax.UCSD.EDU> brian at sdcsvax.UCSD.EDU (Brian Kantor) writes:
> Very very few devices queue an incoming XOFF, which means that extra
> ones don't hurt and are likely more often to help. [...]
> What may have prompted this is using terminal i/o with TANDEM set to
> communicate with some other computer system which does not obey the same
> XOFF/XON semantics as Unix does.  CP/M systems, for example, use XOFF to
> stop output, but will restart it again on ANY character, including
> another XOFF.

	A historical interest note: on vanilla v6 UNIX, XOFF was a toggle;
send one XOFF to stop output, another to restart it.  Given that v6 didn't
come with a pager program, the small amount of time saved by not moving
your fingers on the keyboard was important at 9600 baud.  One of my first
kernel hacks was to add "normal" XON/XOFF processing to the v6 tty driver.
-- 
Roy Smith, {allegra,cmcl2,philabs}!phri!roy
System Administrator, Public Health Research Institute
455 First Avenue, New York, NY 10016

"you can't spell deoxyribonucleic without unix!"