From: becker@super.org (Donald J. Becker) Subject: A brief Ethercard Lesson (was: Ethernet Cards) Date: Fri, 30 Apr 1993 05:45:11 GMT
In article <1993Apr28.211858.23733@colorado.edu> alkar@spot.Colorado.EDU (Ali Alkar) writes:
>
>I am planing to get an Ethernet Card soon and use Linux as my OS.
>Are there any people who bought ethernet cards for their PC's and
>happy or unhappy with the cards they bought. What kind of problems
>have you had when you used Linux with it? What's your card's brand?
>This might save me and many others a lot of trouble since I might
>also post a summary.
\title{Ethercard hardware tutorial}
For impatient users that just want a quick, cheap answer the summary is:
get 16 bit thinnet 8013 cards for $89.
Too brain-damaged to use: 3c501, which is surplus from many places.
Avoid it like the plague.
8 bit ethercards: NE1000, Cabletron E10** series, WD8003, 3c503
Slightly less expensive, but only worth the savings for light use.
16 bit ethercards: NE2000, Cabletron E20** series, WD8013, 3c503/16
NE[12]000: The now-generic name for a bare-bones design around the
NatSemi 8390. They use programmed I/O rather than shared
memory, leading to easier installation but slightly lower
performance and a few problems. The prefix "NE" came from
Novell Ethernet -- Novell followed the cheapest NatSemi databook
design and sold the manufactoring rights (spun off?) Eagle, just
to get reasonably-priced ethercards into the market.
Some recently introduced NE2000 clones use the National
Semiconductor "AT/LANTic" 83905 chip, which offers a shared
memory mode similar to the 8013 and EEPROM or software
configuration.
WD80[01]3: A shared memory design by Western Digital. Over the years the
design has added more registers and an EEPROM. Clones usually
go by the '8013' name, and usually use a non-EEPROM (jumpered)
design. This part of WD has been sold to SMC, so you'll usually see
something link SMC/WD8013 or SMC Elite Plus (WD8013).
The shared memory makes the cards 10-20% faster, especially with
larger packets. More importantly (to me at least) it avoids a few
bugs in the programmed-I/O mode of the 8390, allows safe
multi-threaded access to the packet buffer, and doesn't have
a programmed-I/O data register that hangs your machine during
warm-boot probes.
[[ This part of Western Digital has been bought by SMC. The
SMC Elite and SMC Elite Plus are the same as late-model
WD8003 and WD8013 cards.]]
3c503/3c503/16: 3Com shared-memory ethercards. They also have a
programmed I/O mode that doesn't use the 8390 facilities (their
engineers found too many bugs!) It should be about the same
speed as the same-bus-width WD80x3, but I don't have a 16 bit
version to benchmark.
HP-LAN ethercards: Nicely made, but hard to find. The model numbers don't
encode anything, so you'll have to go by the description.
They use programmed I/O, similar to the NE*000 boards, but the
data transfer port can be "turned off" when you aren't
accessing it, avoiding problem with autoprobing drivers.
3c509: A new card for 3Com, which might be supported soon. It should
be cheap and have excellent performance. The drawbacks are that
it _requires_ very low interrupt latency, and it isn't rated for bus
speeds greater than 8Mhz. The EISA version uses the same
16 bit wide chip rather than a 32 bit interface.
I'm ofter asked "Do you know a source of inexpensive cards?"
I keep track of the current low-price vendors, just because I'm asked
this so often. Call AT-LAN-TEC at 301-948-7070. Ask for their
technical support person, "Vincent Bono". As with all purchases, you
should indicate you are buying this for a Linux system.
The last I checked the price for 10 NE2000s was $670, or $69 ea.!
They also carry a clone, non-EEPROM 8013 board for $89, which is a
better choice if the very lowest price isn't essential.
I've also ordered Alta "Combo" NE2000 cards from Network Express
(aka Main Street Computers) in Fl. A bit more expensive, but
they have bigger ads in Computer Shopper.
If you are looking for prices on your own, try the back of LAN
magazine.
\section{Cables and Stuff}
If you are starting a network from scratch, it's considerably less
expensive to use thin ethernet, RG58 co-ax cable with BNC connectors,
than old-fashioned thick ethernet, RG-5 cable with N connectors, or
10baseT, twisted pair telco-style cables with RJ-45 "phone"
connectors.
Twisted pair networks require active hubs, which start around $300,
and the raw cable cost can actually be higher than thinnet. They are
usually sold using the claim that you can use your existing telephone
wiring, but it's a rare installation where that turns out to be the
case. The claim that you can upgrade to higher speeds is also
suspect, as most proposed schemes use higher-grade (read $$) cable and
more sophiticated termination ($$$) than you would likely install on
speculation.
Thick ethernet is mostly obsolete, and is usually used only to remain
compatible with an existing implementation. You can connect thick
ethernet to thinnet with a passive $3 N-to-BNC connector, and that's
often the best solution to expanding a thicknet.
Thin ethernet is my "ether of choice". The cable is inexpensive. If
you are making your own cables solid-core RG58A is $0.09/ft. and
stranded RG58AU is $0.15/ft. Twist-on BNC connectors are < $2 ea.,
and other misc. pieces are similarly inexpensive. It is essential
that you properly terminate each end of the cable with 50 ohm
terminators, so budget $2 ea. for a pair.
-- Donald Becker becker@super.org Supercomputing Research Center 17100 Science Drive, Bowie MD 20715 301-805-7482