Does anyone use token ring anymore
What was the function of that piece of silicon? The whole die was a cellular transceiver. If I remember correctly that particular spot happened to be empty on the top layer. Foundries require a minimum density of metal on every layer, so we would have had to put dummy pieces of metal there anyways.
We figured why not put a picture. PhantomGremlin 8 months ago parent prev next [—]. Holes are slower than electrons.
So in standard cells the PMOS transistors are made physically larger to compensate. This was another great post. Starting in the upper right, the analog front end circuitry communicates with the ring. The analog front end extracts the clock and data from the network signals.
Is this generally the transceiver chip on the card? The idea of standard-cell logic is that each function such as a NAND gate or latch has a standard layout. Did cell libraries become common around the time of this chip? Even optical cards have this kind of circuitry in the PHY chip. While the SFP module usually contains surprising amount of logic, most of it has to do with configuration and testing and in the end it is just an pair of LEDs with configurable analog amplifiers.
On the other hand for modern ethernet over TP 1Gbps and up the analog interface circuitry is significantly more complex and power hungry , because calling the thing baseband the "base" in "base-T" somewhat stretches the definition of the word. It uses various line coding and signal processing tricks to squeeze all the bandwith out of the wire.
Can you elaborate on why using "base" is a stretch here? I don't think I've heard this before. It's been a while since I've looked at layer 1 but isn't Ethernet just Manchester encoding? What other signal tricks are generally used? Might you or anyone else have any good resources for Ethernet PHY circuits? I vaguely recall the terms, hopefully correctly. High speed on copper, for networking anyway, has gone all analog now. I haven't looked at Ethernet chips in detail, but they have similar analog circuitry.
A "PHY" physical layer module does the analog encoding and decoding. Standard cell libraries are lower-level than IP blocks since you're dealing with gates rather than functional units. I'm sure someone here knows about how they are licensed.
These blocks were built by IBM so the intellectual property itself wasn't an issue. But the blocks were designed by other teams and essentially dropped onto the chip unchanged. For the revised version of the chip, they redesigned the logic but kept the original analog and CPU blocks. My first thought, the way they stand out bare on the chip, seems similar to other RF magic.
In college I tried to do something similar in a term project by using all of the spare surface space on the PCB as a capacitive fill attached to the power supply. If they were test pads something more like the solder ball or a normal pad might be expected. The mystery loops might be some sort of impedance matching.
I visited it a long time ago. If you x-ray? Zenst 8 months ago prev next [—]. I put it aside, it's so old that I won't ever use but probably niche enough today that I felt worth keeping onto or selling over e-wasting it. I encountered the wierd token ring connector for the first time when I joined IBM in the early s.
But the proprietary connector got replaced with a standard RJ45 jack later on. But by that time, it was clear that Ethernet had won. It may have made this chip, but I don't know if the time periods overlapped. I'd be curious to see a comparison with the die of something like the ubiquitious Realtek NICs. They're definitely a mixed-signal design given that everything is on one chip.
Its surprising to learn the cheap and considered crappy RTLAS was technically better than what most would call top of the shelf 3Com 3CB thanks to twice the buffer size 16 vs 8 KB. That vintage Ethernet card you linked to is quite something. I like the big metal-can tuned inductors like a s TV set.
It has a lot of blue bodge wires to fix things. M favorite is the chip with four X's of wire across it. Clearly they designed something backwards. What you described is known as a "Token Bus". A more popular token bus was the Arcnet. I don't know about official releases of documents, but there are a lot of vintage documents on bitsavers. IBM has a very long history of diligent notetaking, maintaining several journals dedicated to internal development stretching back into the 50's.
While I certainly haven't read everything, I've read enough to feel comfortable saying that the quality has had a sharp decline as transparent marketing replaced useful engineering. I suspect I'm not the only one who felt that way, because they recently shuttered those operations and tragically handed everything from what I can tell over to the paywalls. I generally don't feel much one way or the other about corporations, but seeing IBM decay like this genuinely makes me gloomy.
Hacker News new past comments ask show jobs submit. Strange chip: Teardown of a vintage IBM token ring controller righto. It seems dumb at first and is! Ethernet won't work so well for a bus layout, but it works great for a star layout. Token ring is supposed to be awesome on a bus layout, because of how it manages access to the network resources, but it's not something that's better in reality only in theory.
Plus, as devices scale up, the simpler and thus cheaper and easier to design ethernet go there first. Token ring just is not efficient from a cost perspective. We don't use token ring for the same reason we don't use RISC machines -- money and economies of scale :. In any case CSMA vs. If every port isn't directly switched on your network, then someone fucked up.
There's just no excuse. Re:Token ring has too many drawbacks. I've no mod points, but you make some good points - at least, when it comes to LANs. Or, in other words, the advantages that Token Ring has turned out to be unnecessary for the way LANs came to be used. Until recen. It was about some pot smoking elfs, who made trees talk and dwarfs sing right? TR is dead I work for a bank I know we have one small location that still has TR because the site has been on the chopping block for 4 years.
It's finally closing this year. I know we stopped installing it in new locations about 10 years ago in favor of Ethernet. My site and most of the rest of the bank was upgraded from TR to Ethernet Mb about 5 years ago.
Banks and any other large companies are going to stick to industry standards in order to reduce costs and complexity. My point is, why should a large company build a custom LAN network when the cheaper, easier technology will do just fine.
We would have to disable the ethernet adapter in the Dell workstations we use and install TR cards. I have a laptop This is exactly the type of BS that large companies don't want to deal with. Now that massive switches are the norm, it isn't an issue since each user can run in full duplex. If you're on a hub, you're sharing bandwidth. If you're on a switch, you've got Mb all to yourself. Unlike a hub, the switch can buffer the frames if the destination port is busy. In addition, you can run in duplex which means your ethernet card can send and receive at the same time.
And thats just for the cube farm. For the server room we have either dual Mb or dual Mb connections to multiple backbones more for redundancy than bandwidth. There are also dedicated fiber going to SANS drives. The computer in my cube is piggy-backed onto a Cisco IP phone, which all goes to a single Mb switch port.
I have never had a problem with it. Re:TR is dead I have one, made by IBM. I'd sell it. When my office was doing the conversion 5 years ago I told the desktop support group they should not throw away all those TR cards, as they would probably be valuable in a couple of years. I'm wishing I had kept a few for eBay. Oh that takes me back.. Score: 2 , Interesting. Wow, I remember in the s, I used to have corporate customers that would order token ring cards at a time.
Unfortunately, IBM couldn't deliver. They're probably still on backorder. Re:Oh that takes me back.. Government Score: 2. I know for a fact that the state of California still deploys token ring, but I can't give you my direct source sorry.
A Google search [google. This PDF [ca. Provide design for routed solutions for many LAN protocols in the Ethernet or to. I believe my company still uses some token ring cabling to carry ethernet. You have to put this funny adapter on the end at each end and then the token ring cable will carry ethernet. It cant go any faster than Mbps though. I think they are supposed to replace it next year when a large part of the company moves buildings.
No, except for this one guy, Score: 2. I have a friend who inherited a working install between a bunch of OLD wireless access points for an inventory system. He has converted everything else over to the Ether Bunny, but his management is not in the mood to put in and replace a bunch of RF equipment. Token Ring It is funny this came up.
I submitted this as an article just today, but it was rejected grouse, grouse. Anyway, it lists Token Ring as one of the top flops of IT in the last 20 years. I have actually never used a token ring network, but this is stuff I always thought about it when I read about it: Network World's [networkworld.
Token ring Score: 2. I don't think anyone has seen the Token ring since that hobbit lobbed it into the volcano a few years ago. Token Ring was a good tech for the time until the early 90's , but switched Ethernet killed Token Ring. Later there was faster switched Token Ring as well, but by that time Ethernet was so cheap Token Ring no longer made sense to implement. It was cheaper to replace existing infrastructures with inexpensive Ethernet than to upgrade the old Token Ring networks.
You know, you could have almost the same conversation about ATM. Why its gone Score: 5 , Informative. If you had a big, flat network it just plain wouldn't work. Look at why: With token ring, only the card holding the token could transmit. Everybody else had to wait for the token. So each station would empty its transmit queue and then pass the token on to the next station.
On ethernet, a station would send a packet whenever and if another station sent a packet at about the same time they'd collide.
Every station observing the collision would assert a collision signal and after the collision signal cleared the two stations that transmitted would wait a random period of time and then retransmit. That's oversimplifying a bit but more or less correct. So, token ring was much more stable in a large LAN with a high probability of multiple stations having outbound traffic ready at the same time.
When you're plugged in to a switch there are only two devices in the collision domain: you and the switch. So, lots less collisions. When you're in full duplex mode as you generally are , collisions are impossible since by definition both sides are allowed to transmit at the same time. And if the nic in the PC burns out, the rest of the network doesn't care. Token ring is very sensitive to malfunctioning nics. A malfunctioning nic may drop the token, that is it may receive the token and then fail to transmit it to the next nic.
That kills a token ring network dead until the admin wanders around with an analyzer and figures out which PC is at fault. Suddenly the tables were turned. Token ring was an administrative headache and expensive to boot. Ethernet was simple, cheap and worked just as well. Token ring died out except as an academic curiosity -- an interesting early answer to a problem that was eventually solved another way. Only weird applications still need token ring Score: 5 , Insightful.
Sometimes you've got old IBM equipment that was working fine in the early 90s and you didn't replace for Y2K, and because you don't want to touch the computers, you don't need to change the routers.
Or sometimes you've got a building cable duct full of asbestos so you don't want to touch it, but there's too much metal in the building for wireless to work reliably. Basically, token ring was old a decade ago. Why Ethernet didn't work, the real story Score: 5 , Interesting. So that's why. No Score: 2. Did you really need to ask that in order for it to be answered?
Hmm Score: 2. Token-Ring based LAN is dead. I can think of several reasons. The first one is cost. The ethernet equipment is cheaper.
The second is management. With ethernet hubs, you get all the management capabilities you need and none of the disadvantages of the token-ring e. The 3rd: ethernet switching is predominant vs collision based classical ethernet , so you have a constaant response time as well. That does not mean that a token-ring based protocols are dead. A ring configuration is still a viable option, say, to connect multiple routers over large distances, say km. But as a LAN, token ring is pretty much dead.
An interesting titbit. I was working for IBM at that time a few years ago, around , a highly confidential message came from the top: "IBM is migrating internally from Token-Ring to Ethernet. Are you kidding? That franchise is played out. Old news. Last year. If they could have worked out the rights to The Hobbit in time for Christmas , then maybe there'd be time for one final she-bang, and perhaps a TV spinoff or two - but by now people've moved on to World of Lovecraft.
Outdated school book Score: 2 , Interesting. Well, we are using a book in my electronics course that teaches about computers. The book was revised in It states how ethernet networks are not commonly used due to frequent collisions. It also refers to infrared networking as an efficient means of communication.
In the operating systems section, it teaches us that while reformating a computer, just use FAT16 if in doubt of a fs to u. Re:Outdated school book Score: 2. Can you give us the book's title and author, so I can recommend it to my enemies?
I had a modern schoolbook like that too, not too many years ago. It taught me about winchester drives, and that's all I have to say about that.
Still selling A small shop unit opened up on our campus last year selling cheap laptops, mobile phones etc etc. Legend has it that a fresher wandered in to get a network card for his PC to connect to his residence room network point and was sold a token ring card.
But doubtless the tale will grow in the telling Not even at IBM Score: 5 , Interesting. Myself and my wife work for IBM. She had to write all the code on a terminal connected to a mainframe and cross-compile to the PC because the PC's couldn't handle the code. However, the products are still supported, and not uncommon in mainframe installations. At IBM we finished the Ethernet migration a couple of years ago.
The thing that struck me the most about the migration was how converting from 14Mbps TR cable to Mbps Ethernet cable involved nothing more than inserting an adapter cube into the connector on each end of the building cabling. One of the primary features of the "IBM Cabling System" was that it could be adapted to many different cable types by just using adapters; coax, twinax, UTP, etc.
This made it hideously over-specc'd for the original common use of TR. The cabling was designed so you could run it past just about anything and not have to worry about interference, cross-talk, etc.
You could even get cable that had some UTP pairs stuffed between the shielding and the sheath so you could run your phone and data cabling using the same cable run. The drawback was that the cabling was bulky, expensive, and difficult to work with. Making cable that will actually work at over six times it's origninal intended speed while being more than a bit difficult to work with is an interesting example of Enterprise-quality engineering philosophy at IBM from the '80s. Re:Not even at IBM Actually, you can still buy token ring pcmcia cards from IBM if you're a large enough customer as my employer is.
You'd actually be doing IBM a favour by taking them off their hands. Of course selling refurbished kit has always been a key element of IBM's business model. They seem to try to deal with collisions by each station learning and knowing when it is ok to send. If a computer doesn't have a token, it has to wait until the token is freed. This ensures that no two computers can try to access the wire at the same time, making bandwidth usage more efficient.
Second, Token Ring allowed for larger packet sizes than Ethernet. The maximum packet size you could have in an Ethernet frame was bytes. Token Ring packet sizes depended how fast your line speed was. If you were running Token Ring at 4 Mbps, you could have a packet size of bytes. If you ran Token Ring at 16Mbps, you could have a packet size up to 18, bytes long. Obviously, larger frame sizes mean that you could transmit more data in each packet, reducing the total number of packets on the wire.
This lead to less congestion in routers and network cards. Finally, you had the line speed advantage of Token Ring over Ethernet. Even though Token Ring only first shipped at 4Mbps speed while Ethernet ran at 10Mbps, because of token-passing and frame sizes, you could actually get better performance out of a 4Mbps Token Ring installation. IBM then cranked the speed up to 16Mbps, which had the added benefit of gaining a marketing advantage.
Even if people didn't understand how 4Mbps Token Ring was faster than 10Mbps Ethernet, the 16Mbps speed would overcome that. In this case, it probably had more to do with greed and advancing technology. Ethernet grew ever increasingly faster, going from 10Mbps to Mbps, to where we are now with Gigabit Ethernet and 10G Ethernet. Even though Token Ring was more efficient - to the point that on an unswitched Ethernet segment 16Mbps Token Ring could still be faster than Mbps Ethernet in some cases - eventually the increasing Ethernet speeds overwhelmed Token Ring.
Added to that was the fact that vendors started introducing switches which eliminated the problems of collisions which slowed down Ethernet networks in the first place. This completely removed one of the major technical advantages that Token Ring had over Ethernet.
Switching and Mbps speeds make 16Mbps technology obsolete. Probably the main reason why Token Ring failed however was pricing. This made all Token Ring equipment too expensive.
0コメント