EPORTS & TB+

[Leslie Mikesell]

In article <1990Jul31.144823.13802 at robohack.UUCP> woods at robohack.UUCP (Greg A. Woods) writes:

Re: ports that can't do both hardware flow controll and xon/xoff

>> > You can't
>> > even set HFC with an stty, rather you have to use epstty.  It was a
>> > really brain-dead, stupid thing to do, especially after almost every
>> > other vendor had used (usually the same) un-used bits in a termio flag
>> > to do the same.
 
>Unfortunately there are enough free bits to allow a choice.  Without
>the leadership of AT&T by putting such features in the porting base,
>we end up with in-compatible flags and manifest constants for
>different vendors, making it really difficult to maintain portable
>code. 

The right way to do this without causing coding problems is to provide
different device names for the same port with and without HFC.  However,
this can still cause trouble if you use the name of the device in a
locking scheme.

>Not only that, but with so many vendors out there who don't
>know how to make rs-232 ports work (including, this time, AT&T), we end
>up with a lot of broken drivers.  I've been banging my head against
>AT&T's minimalist attitude for a long time now.

Amen. How many years were smart modems around before it was possible
to dial them reasonably (the \M,\m tokens in Dialers)?  It wouldn't
have been possible to do this in combination with uugetty before
the SysVr3 release because an open without O_NDELAY (uugetty's)
would never complete if another process opened the same port
with O_NDELAY.

Now, they still don't believe that people might use a speed-matching
modem with HFC for an interactive application where xon/xoff is needed.

>As for your suggestion that there are better ways to do it, I'm
>interested in what you think.  I've been puzzling over these kinds of
>things for quite a few years now, and perhaps I'm stuck in a rut.

Why doesn't everyone just provide HFC by default, always on?  If you
connect to a device that doesn't support it, all you have to do is
loop back the computer's RTS to CTS.  I can make up a custom cable 
a lot faster than waiting for AT&T to make their software work (Has
it been 5 years already?).

Les Mikesell
  les at chinet.chi.il.us