info-3b2@lamc.UUCP (Info-3b2 Mailer) (01/04/89)
Info-3b2 Digest, Number 47
Wednesday, January 4th 1989
Today's Topics:
Re: Intermittent Ports Hanging
Re: Intermittent Ports Hanging
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From: cogsci!cs.buffalo.edu!sigmast!dgy
Subject: Re: Intermittent Ports Hanging
Date: Tue, 3 Jan 89 8:29:34 EST
> Has anyone experienced ports problems,primarily with cu while
> using either the eports or standard ports hardware? It seems that
> this happens at least once a week on some machines I use.. Usually
> using cu to access another machine at speeds of 9600 and up.. The
> task never terminates,and a reboot is neccessary. I have tried using
> a breakout box to drop cd,dtr,etc to cause the port to recycle,but
> nothing avails.. I am running 3.1.1 with the latest eports drivers.
> Enquiring minds would love to know.
I'm glad someone else is having this problem! We are also running 3.1.1
with eports 1.2, and have the same problem. In our case, it usually
happens when someone is dialed out to a VAX with VMS, at 1200 or 2400,
and it doesn't matter if the modem itself is on the eports board, just
the terminal being used. The entire board locks and we have to reboot.
I talked to the AT&T hotline about it, and they recommended checking the
total baud rate across all terminals on the eports board, which doesn't
appear to be the problem. They said they couldn't help otherwise, as
we have non-AT&T terminals on the board.
--
Dave Yearke, Sigma Systems Technology, Inc.
5813 Main St, Williamsville, NY 14221
...!sunybcs!sigmast!dgy
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Subject: Re: Intermittent Ports Hanging
From: pacbell!bcr!auxnj!jon
Don't know if all the reported symptoms are due to the same problem,
but yes, both the ports and eports cards have specified
MAXIMUM AGGREGATE BAUD RATES
On the ports card, it is 19.2K for the 4 ports.
On the eports card, it is 38.4K, but I am uncertain if this is for all
8 ports, or 2 X 19.2 for 2 sets of 4 ports each.
This would not be so bad if upon overload, processes were simply suspended
til output could occur. However, there is a defect in the hardware?/driver?
that as reported, hangs irreversibly, the ENTIRE BOARD.
We solved the symptoms, not the defect, by two techniques.
1) Balancing port assignments to mix high speed ports with fixed rate
low speed ports (Ex. a 1200 baud modem with a 9.6K laser printer)
2) Limiting terminal access to 4.8K baud. This proved to be a
problem, but not a system administration one. It was a user
education problem. Sure, we set the gettys to 4800 baud,
even went around resetting terminals. But the users would
login at 4800 baud, then issue a "stty 9600" or "stty 19200"
and reset their terminals accordingly.
BTW: the worst offenders protested "I did not change my baud
rate. Must be some other problem!" Caught their lies
by examining their ksh history files. Never told them
how we knew however -- keep it in mind.
Any way, by being slowly responsive to the worst offenders,
reboots in the middle of the day are a pain to productive
users, everyone now accepts the slower speed and we have not
experienced a repeat of the problem for about a month. It
was occuring twice a day.
Definitely not a fix, but perhaps a work-around.
Jon LaBadie
Cincinnati Bell Information Systems
{bcr, att, attmail}!auxnj!jon
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