Path: utzoo!utgpu!water!watmath!clyde!att!pacbell!belltec!jim
From: jim@belltec.UUCP (Mr. Jim's Own Logon)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Ethernet cards for an IBM PC
Summary: What the main differences are...
Message-ID: <239@belltec.UUCP>
Date: 11 Jul 88 14:52:58 GMT
References: <4424@sphinx.uchicago.edu>
Organization: Bell Technologies, Fremont, CA
Lines: 37

In article <4424@sphinx.uchicago.edu>, cjdb@sphinx.uchicago.edu (Charles Blair) writes:
> 
> Can anyone recommend an Ethernet card for an IBM PC? I'm looking for a
> good cost/performance value. Responses via e-mail preferred. Thanks.
> 
> -- 
> Bitnet:	  	 lib.cb@uchicago.bitnet
> Internet:      lib.cb@chip.uchicago.edu
> uucp:	  ..!ihnp4!gargoyle!sphinx!cjdb

   As with most add in cards, there are two basic classes of boards: intelligent
and slave. The slave type cards are basically an Ethernet controller chip
with DMA capability (National 83980, Intel 82586, etc.) and a dual port memory.
Incoming packets on this type of board have the station address recognized
by the controller chip and then the packet is stored in the dual port memory
at the address that was set up before hand. At the end of the packet, an 
interrupt is sent to the host (the 286 or 386) and then it fetches the packet
down to main memory. No processing is done on the Ethernet card.

   Intelligent Ethernet boards can do all this and more. On incoming packets
they can preprocess the information before alerting the host that it has
information. It can have DMA logic with the AT bus so it can also transfer
the packet to main system memory (but this is not a win for UNIX systems, stick
with the dual port RAM). Outgoing packets can be assembled from various 
pieces by the intelligent card before sending. Network performance and 
statistics can be done by an intelligent card. And perhaps most important,
UNIX communication programs can be run entirely on the intelligent board, off
loading the main processor.

   So you get cost vs. features trade offs on the two classes of boards. Just
to justify typing this in, Bell Technologies sells a slave Ethernet controller:
Intel 82586, 16K dual port RAM, full UNIX drivers for TCP/IP, SNAP, RFS and   
maybe more by now (I'm the hardware guy, what do I know about code?). Cost is
very low. Call a sales person at (415)659-9097, or outside Ca. at 800-FOR-UNIX.

						-Jim Wall
						Bell Technologies Inc.