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From: jfjr@mbunix.mitre.org (Freedman)
Newsgroups: comp.sys.ibm.pc.programmer
Subject: performance of XMS vs EMS
Message-ID: <1991Jan30.140124.22332@linus.mitre.org>
Date: 30 Jan 91 14:01:24 GMT
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  To all who have replied, thanks and my apologies for not being clear.
I aware that I have extended memory and I have books/manuals on both.
Here is my question rephrased and detailed.

   I have a Compaq 386/20e running DOS 3.3 with 4 megs of memory.
I have the Clarkson packet drivers installed and I am building
a TCP/IP analysis tool. One of the things I would like to do
is to sit on the net and just receive and record all packets
(time stamp them) for a while. I can receive and I have
a millisecond timer (thanks for the help folks). The packets
can come at me fast - up to 1.5k a packet with 2-3 millisecond
separation-. My receiver runs at interrupt level as does my timer.
Both EMS and XMS involve some fiddling around at interrupt level.
I am concerned about stepping on my own feet with either approach.
I am not concerned with portability or price. Just performance.
full protected mode might be nice but I have to support the
packet drivers too. I can get more memory or fancier hardware
if I really need it(I think;) ).

  So what is the best choice EMS with its timeconsuming paging,
XMS with switching back and forth from protected mode?.
Anybody got advice.



                                 Jerry Freedman,Jr