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Article #7Re: Need help selecting Ethernet cards for very high throughput rates.
From: Chris Torek
Date: Tue, 03 Sep 1991 04:56
Date: Tue, 03 Sep 1991 04:56
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In article <1991Sep1.195029.16374@aber.ac.uk> pcg@aber.ac.uk (Piercarlo Grandi) writes: >... The 16 bit ISA bus runs at 8Mhz and transfers 16 bit across. Taking >account of all hw protocol overheads it can sustain between 5-6 MB per >second. (I know nothing of the ISA bus and little of PC architecture in general, and will just take the above for granted.) Given this bus speed, you can get 1.25 MB/s out of your Ethernet, although you may have to be careful: if you use the bus twice for each 16-bit word sent---and it is easy to do this in some architectures---you will take 2.5 MB/s out of your 5 or 6. This leaves the other half of the bus bandwidth for whatever else goes on. (If you touch it more than twice you will get into trouble---anything like that implies that there are other devices doing the same.) Ideally, you will touch it only once. >32 bit EISA Ethernet cards are an expensive joke, as is any "turbo" interface >between a 40MB/s 32 bit bus (EISA) and a 0.8MB/s 1 bit one (Ethernet). Actually, Ethernet is 1.25 MB/s (10 over 8 = 1.25, not 0.8). -- In-Real-Life: Chris Torek, Lawrence Berkeley Lab CSE/EE (+1 510 486 5427) Berkeley, CA Domain: torek@ee.lbl.gov
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 10a29b,adc43bc691337774 X-Google-Attributes: gid10a29b,public X-Google-Thread: f9325,adc43bc691337774 X-Google-Attributes: gidf9325,public X-Google-Thread: 12ca36,bf24dff74f21bc6 X-Google-Attributes: gid12ca36,public X-Google-Thread: 1048e3,adc43bc691337774 X-Google-Attributes: gid1048e3,public X-Google-Thread: 10f9b1,adc43bc691337774 X-Google-Attributes: gid10f9b1,public X-Google-Thread: 1122ea,adc43bc691337774 X-Google-Attributes: gid1122ea,public X-Google-ArrivalTime: 1991-09-03 00:55:58 PST Path: arc1-ca.pugleaf.net!gmdzi!unido!mcsun!uunet!zaphod.mps.ohio-state.edu!casbah.acns.nwu.edu!ucsd!dog.ee.lbl.gov!elf.ee.lbl.gov!torek From: torek@elf.ee.lbl.gov (Chris Torek) Newsgroups: list.sco,comp.protocols.tcp-ip,comp.protocols.tcp-ip.ibmpc,biz.sco.general,comp.unix.sysv386,comp.unix.wizards Subject: Re: Need help selecting Ethernet cards for very high throughput rates. Message-ID: <17161@dog.ee.lbl.gov> Date: 3 Sep 91 04:56:41 GMT References: <1991Aug27.192220.20958@world.std.com> <1991Sep1.195029.16374@aber.ac.uk> Reply-To: torek@elf.ee.lbl.gov (Chris Torek) Organization: Lawrence Berkeley Laboratory, Berkeley Lines: 23 X-Local-Date: Mon, 2 Sep 91 21:56:41 PDT