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- Newsgroups: comp.sys.sgi
- Path: sparky!uunet!sun-barr!ames!sgi!rhyolite!vjs
- From: vjs@rhyolite.wpd.sgi.com (Vernon Schryver)
- Subject: Re: Incoming UUCP flow control problem?
- Message-ID: <pauogvg@rhyolite.wpd.sgi.com>
- Organization: Silicon Graphics, Inc. Mountain View, CA
- References: <1992Sep1.152548.19218@alias.com>
- Date: Wed, 2 Sep 1992 03:06:08 GMT
- Lines: 40
-
- In article <1992Sep1.152548.19218@alias.com>, chk@alias.com (C. Harald Koch) writes:
- > We have a SGI IRIS-4D/80S running IRIX 4.0.1 with a 6-port serial board.
- > There are two modems used exclusively for UUCP connected to the on-board
- > modem ports, and four more modems connected to the 6-port board. All modems
- > are Telebits; the two UUCP modems and two of the others are TB+; the
- > remaining two are T2500s.
-
- What is a Telebit "UUCP modem"?
-
- > ....
- > This looks suspiciously like a flow-control problem....
-
-
- Using a break-out box in series with the computer and each modem, test
- to see if dropping RTS or CTS stops output from the appropriate
- device.
-
- Using two break-out boxes in series with two modems, call one modem
- with the other using cu. Again test the effects of RTS and CTS. Use
- control-S to cu to make the one side stop receiving, and `cat bigfile >
- /dev/ttyfZZ` to stuff a bunch of data down the other modem. See if the
- computer drops RTS, and then see if the far modem drops CTS. Reverse
- and try the other direction.
-
-
- If all of that fails to uncover bad cabling or modem settings, check to
- see that the 4D/80 is not suffering long periods of interrupts being
- disabled. Each "kernel printf" turns off interrupts for its duration.
- While interrupts are off, in-coming flow control is not handled.
-
- Output flow control is done by the hardware. That you see UUCP file
- transmissions fail implies the problem is in the modems or the
- cabling.
-
- Please note that 6-port boards with the older firmware will generally
- get less than 960 B/s through UUCP. I do not know how you might get
- the new firmware. It requires IRIX 4.0.5.
-
-
- Vernon Schryver, vjs@sgi.com
-