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.