echoing style - DOS,VMS vs. Unix (was: AT&T Joining OSF)

[Guy Harris]

> The real advantage of delaying echo is input gets put on the screen where
> it belongs, not where the cursor happened to be when the character was typed.
> This is a plus for "cooked" mode applications which use cursor movement.

It's worth noting that boatloads of applications that run in "full-screen"
mode, such as many popular screen editors, give you delayed echo as a result of
turning the kernel's echoing off and doing the echoing themselves.

> The "new tty" line dicipline on my Sun which I presume either Berkley or Sun
> did

Berkeley.

> I think this would be done in a streams layer on Sys V.3 but I'm not sure.

It's not; S5R3 has streams, but doesn't use them for ttys (except maybe in some
cases).

> Does anyone know if line diciplines are obsolete and replaced by streams
> stuff?

In SunOS 4.0, they are; I don't know of any other UNIX version has completely
tossed out the "old"-style tty driver and line discipline mechanism in favor of
streams-based drivers and modules.  The SunOS version offers a superset of the
S5 "ioctl" interface, with an additional streams module to translate V7 and BSD
"ioctl"s into the new ones; it also has the BSD-style user-interface
improvements you alluded to (such as handling "CRT erase" correctly).