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From: rog@ingres.com (Roger Taranto)
Newsgroups: comp.sys.3b1
Subject: Re: some uucp transfer rates for 3b1 w/ telebit
Message-ID: <1991Jun2.231810.7514@ingres.Ingres.COM>
Date: 2 Jun 91 23:18:10 GMT
References: <1789@hico2.UUCP> <1991May29.224256.24529@ceilidh.beartrack.com>
Reply-To: rog@Ingres.COM (Roger Taranto)
Organization: ASK Computer Systems, INGRES Products Division, Alameda, CA 94501
Lines: 24

In article <1991May29.224256.24529@ceilidh.beartrack.com> dnichols@ceilidh.beartrack.com (DoN Nichols) writes:
>In article <1789@hico2.UUCP> kak@hico2.westmark.com writes:
>>I suspect that a 3b1 can send faster than it can receive.
>
>	That, I believe, has been the general concensus of the discussion.

That seems to make sense.  It seems to me that terminal drivers and
interrupt routines were designed to be able to send lots of data, but
receive comparatively low amounts.  (How many users do you know who
can type at 19200 bps?)

We have a brave, little microvax II with 4 Telebits connected; it serves
as our UUCP and news machine.  We can get ~14500 bps on our outgoing
connections, but we can't do better than ~9700 bps on the incoming
connections.  With nothing else going on and just one UUCP connection
(incoming), the CPU is pegged at ~93-95% trying to handle the single
character interrupts for that uucico process.

I imagine that the 3B1 is similarly handicapped, i.e., it's running out
of CPU trying to handle single character interrupts while receiving
data via the serial lines.

-Roger
{mtxinu,pacbell,amdahl,sun,hoptoad}!rtech!rog		rog@ingres.com