3B2/310 & TB+
Greg A. Woods
woods at robohack.UUCP
Sun Jul 29 05:20:42 AEST 1990
In article <470 at mtndew.UUCP> friedl at mtndew.UUCP (Stephen J. Friedl) writes:
> All 3B2s have console and contty ports, and these ports are on the
> motherboard and serviced by the main CPU (by the DUART driver). They
> can handle quite a good data rate -- sustained full 19200 bps output --
> but they degrade quickly when the system gets busy. We tell our customers
> to stick a 2400bps modem on the contty port because that's a pretty slow
> speed and is likely to be working even if the other serial cards go down
> (so we can dial in and fix stuff).
Even sustained UUCP at 2400 on contty can be a significant load on a
system. However, it is true that contty will likely be one of the
last ports on a system to die.
> moving the cursor back. It can be maddening, so I "fixed" it by
> define the cursor-left character in terminfo as ESC[D. Sending
> three characters is MUCH faster than waiting on the delays.
I've never seen this. I know it is possible to put backspace delays
on a port inside the termio driver. Perhaps the default on PORTS was
to use this delay (for those old 33's you know). I would hope you
could turn off the delay with an ioctl() though.
> PORTS HPP is purported to be a high-performance version, but I
> don't know much about it (others are welcome to chime in here).
> I have heard that this was originally developed with the military
> in mind, but that very well could be idle gossip. I don't know
> if it has the same backspace delay bug.
This one does seem to work just fine, though it lacks hardware flow
control. I ran two 2400 bps modems, and my dmd at 19200 on it for
quite some time with no problems.
> They support CTS/RTS flow control, but it is done in a way that
> makes them not very helpful for many of us. The big bug is that
> CTS/RTS is mutually exclusive of XON/XOFF -- you can never run
> both at the same time.
This is a serious design flaw in the EPORTS driver and firmware!
> data rates this time can be significant. I'm told that "skid" of
> 32 or 64 characters is not uncommon, and all the HP LaserJets
> that I've seen can't deal with this. You gotta either slow it down,
> use hardware flow control, or use a parallel port.
It's too bad you can't set the port priorities in order to close the
window.
> Finally, the EPORTS have had >tremendous< problems in the past
> with bugs. I have had several customers ready to throw their
> computers out the window due to EPORTS problems, and only in the
> last year or year and a half has it been better (with the 1.3
> driver). I understand that the EPORTS folks in Lisle had a very
> miserable summer of 1988.
The still do. Well, maybe not quite as bad. I seriously wonder if
any of the drones at AT&T can write firmware (the 705 MT's I've been
testing have serious firmware problems, even at rev.1.2). The EPORTS
with 1.3 drivers still hangs occasionally on every modem except the
AT&T 2224B. I've put my 1200 on the PORTS/HPP card, but the Microcom
I had for a while required HFC, and was a real pain in the butt. I've
seen reference (in the newest 3.2.2 docs) to a new command (relport)
(though I've not tried it yet), which the documentation purports to be
able to release a port from a hang without re-pumping the card (and
dropping all connections).
It is a real screamer though!
--
Greg A. Woods
woods@{robohack,gate,eci386,tmsoft,ontmoh}.UUCP
+1 416 443-1734 [h] +1 416 595-5425 [w] VE3-TCP Toronto, Ontario; CANADA
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