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From: romkey@ASYLUM.SF.CA.US (John Romkey)
Newsgroups: comp.protocols.tcp-ip.ibmpc
Subject: SLIP failing at high baud rates?
Message-ID: <9104221655.AA23743@asylum.sf.ca.us>
Date: 22 Apr 91 23:55:45 GMT
References: <9104222012.AA21176@ftp.com>
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: romkey@asylum.sf.ca.us
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   Date: Mon, 22 Apr 91 16:12:39 -0400
   From: Gordon Lee <gordon@ftp.com>
   Reply-To: gordon@ftp.com

       From: David Gunderson <fluke!dag@beaver.cs.washington.edu>
       Subject: Re: SLIP failing at high baud rates?

       The reason that you can "lose" interrupts on the PC COM ports is not
       entirely related to the COM port hardware itself. There are some
       BIOS implementations (mostly related to display adapters) that feel
       free to disable interrupts (execuite a CLI instruction) any time
       they want to. 

   In the case of most SLIP/PPP drivers, BIOS is circumvented entirely.

That was my first reaction, too, but I think what David Gunderson was
saying is that there are other parts of the BIOS, not the COM drivers,
that disable interrupts and may increase the interrupt latency in the
system to the point where it can't help but drop characters.
		- john romkey			Epilogue Technology
USENET/UUCP/Internet:  romkey@asylum.sf.ca.us	voice/fax: 415 594-1141