I am <i>so</i> happy that coax bus based ethernet died. One of the hardest to track bugs for me involved a machine named 'chopper', an SGI box set up to monitor a bunch of other machines. Every now and then chopper would report one of the other machines on the network as down, and send out a page to an operator, which got quite annoying. We tried everything we could think of to trace the fault, replacing all the bits and pieces, including entire servers to figure out what was causing the problem.<p>Eventually the only thing left that we had not swapped out was a BNC 'T' connector at the back of the MAU of chopper itself, the one that was used to put it on the coax bus.<p>My buddy Jasper and I both looked at each other at the same moment around 4 am or so, bleary from sleep 'that can't possibly be it', let's swap it out. And sure enough that was it.<p>Apparently that particular 'T' connector had electrical capabilities unlike any other 'T' connector produced before or after. It managed to filter out 'ping' reply packets from the IP address of the server reported as down...
It's pretty interesting to read into the original "broadcast" ethernet specs.<p>The "thick yellow wire" and the "coax" both had a single broadcast domain for all devices on the segment. You then linked segments with a bridge (so you could scale networks).<p>Some things I find interesting about them:<p>1) The idea is based on radio broadcast (ALOHANET). Since you're using radio broadcast there, a single collision domain makes sense. <a href="http://en.wikipedia.org/wiki/ALOHAnet" rel="nofollow">http://en.wikipedia.org/wiki/ALOHAnet</a>. The protocol is best understood as "room full of people shouting at each other". Don't start talking if something else is, and if two people start at the same time, you both back off. Simple as that.<p>2) If two nodes try to transmit at the same time, you get a collision and both retry. The spec has a random retransmit timer to avoid immediate (and perpetual) recollision. Requires fair nodes...<p>3) The max cable length and packet size and related via the speed of light (in copper): <a href="http://www.wildpackets.com/resources/compendium/ethernet/propagation_delay" rel="nofollow">http://www.wildpackets.com/resources/compendium/ethernet/pro...</a><p>4) It was (semi-)reasonable to use a "vampire tap" connector to dig through the insulation and into the core of a the "thick yellow" copper cable. Just don't wiggle it and cut the copper (or introduce too much of an edge and get signal reflection and hence more collisions).<p>5) When you had a copper connection between all the ports on your network, an etherkiller really <i>meant something</i>. (A cable, mains plug on one end, coax connecter on the other. Plug in and fry every network card on the segment). RJ-45 etherkillers are single-target. Pah.
One network which I have a particular fondness for is Arcnet. It also used "thick ethernet" (93Ω) cabling, but all stations were connected to a central hub. It was remarkably resilient.<p>I used it a lot for gaming (LAN parties), back in the days when Ethernet (that's thin coax ethernet) cards were still expensive. Arcnet equipment could be obtained for cheap (or even free), the speeds were enough for gaming (Doom, Quake, Descent), the DOS drivers were great, and overall it was a great solution which Just Worked. Most importantly, it didn't have the problem of one person bringing down the entire network just by disconnecting the cable at his station, which thin ethernet had.<p>See <a href="http://en.wikipedia.org/wiki/ARCNET" rel="nofollow">http://en.wikipedia.org/wiki/ARCNET</a> for more details.
Wow, this is a blast from the past, circa 1992-1998. For my sins I used to maintain a fairly large Thick Ethernet network for a large textile manufacturing company in the UK (working for a contractor that basically had very few clues about employee health and safety, hindsight is a wonderful thing).<p>A fair chunk of this network ran through their factory up in the factory roofspace. I used to climb these ridiculously high step ladders to reach up into the factory roof steelwork to install "vampire taps".<p>It used to scare the bejesus out of me, mostly due to an aversion to heights, the other being that the factories produced cotton thread, which during one of the processes requires the application of a fine mist of wax or light grease, I don't remember why. But every high up surface was deceivingly lubricated with a fine layer of wax or grease as a result of being kinetically atomised into the air by high speed thread spinners, rollers, spoolers and guides. To further focus your mind, there was also an opportunity of being impaled on these massive crane lifted pointy multi-spool holder things should you put a foot wrong (they were used to lift large bulk spools of rough spun cotton into even larger dying machines).<p>Although we had a proper coring tool my biggest fear was of creating a short between the shield and core and unf*cking that up a 30 ft step ladder in that environment would have ruined my day (we had to install these things on live segments, there was no downtime permitted). Fortunately the quality and accuracy of the tooling was good, the customer used the correct cable (not some cheap imitation) and my karma and anxiety levels could return to normal once the transceiver lights flickered into life.<p>Just thought I'd share my lasting memory and experience of 10BASE5 hands on work.
I hope he enjoys going round and working out which ethernet connector has fallen out, because of those useless "slide locks". I definitely don't miss thick ethernet.
I actually have a couple of old PCI ethernet cards that have both standard RJ45 connectors and BNC coax connectors. Does that mean I actually have something rare?
I remember when I first mount a network on my house to play with my brother DooM , with coax Ethernet and with a few ISA network cards that I got for free...
next you have to try the old standard of terminating either or both ends of your thick ether with thin ether (and then real terminators at the far ends of that)<p>(and yes thick ether standardly came with connectors on the end, I still have a roll somewhere, I have no idea why)