So they’re upgrading to 3.5" and token ring?
What’s a token ring?
Also I’m pretty sure I still have a box of 3.5” they can have lol
What’s a token ring?
Wait-your-turn Internet
Until someone forgets the terminator on one end of the network and the token falls out
If it’s stupid and it works, it ain’t stupid.
It comes from a time when wired infra was a shared medium and only one party could talk at a time. To control who talked, they passed around a token. The token would essentially take a lap around the ring before you could speak again.
Because it’s a shared medium, it’s one big collision domain.
Now, collisions are bad, mmmkay.
Modern wired infrastructure is switched. There’s some brains in the operation. The switch learns the hardware ID (unique MAC address) of every device that’s talked to it, because every frame that goes through it has the source and destination hardware ID as part of it.
As such, the switch will only forward out the port where it knows the destination is. It can only know it from one (logical) port (if there’s more than one, that’s a paddlin’). If it doesn’t know it, it’ll forward the frame out all interfaces except the one it rode in on.
Compare this with modern wireless where, aside from 802.11ax, clients just… (essentially) wait for a random amount of time, listen for a break in the signal, and take a leap of faith. It’s amazing anything works on wifi with how much modern homes stress them.
802.11ax, clients just… (essentially) wait for a random amount of time, listen for a break in the signal, and take a leap of faith.
Ethernet originally worked the same way, back when it competed directly against token ring. Ethernet won by being as reliable in real world scenarios while being cheaper to build out. Gigabit Ethernet was the first standard that insisted on full duplex only.
Half duplex mode with the collision avoidance is still actively supported for 10/100, but it is becoming very hard to find an unswitched hub. So you may have to write up your own twisted pair cables.
Yeah…kinda left a lot of the layer 1 stuff out of it when I segued into modern ethernet. I could’ve really ranted.
That was still really close to modern Ethernet when 10BaseT and 10Base2 were out. It was the switched networks and Spanning Tree that really made ethernet win out, by supporting full duplex and scaling way betterer.
Although if I remember correctly, and I could be off because most of this was before my time and I learned from a greybeard who came up on Token Ring…the same physical media for both 10Base2 (the coax with bnc ends, T’s at each station, and a terminator on each end) and later 10BaseT (UTP CAT 3, if we are being contemporary) Ethernet did end up getting used for Token Ring as well, just different hardware. And I think IBM was actually able to squeeze more bandwidth out of the same wires for a while, too.
Honestly if not for switched Ethernet and Spanning Tree, Token Ring would’ve had several more years of life left in it, at least.
Modern 802.11ax (Wifi6) borrows a little bit from the methods of token ring by having the AP essentially schedule timeslots for each of the clients…but it won’t make much improvement till most (if not all) of the segment (that is, devices connected to any one radio) is ax or higher. I believe (and don’t quote me on this), that is very similar in concept to how the later generation token ring MAUs worked.
You can still do 10Half on some high end managed switches. But most SFPs and mGig ports won’t go down that low, and mid-range enterprise access switches are getting fewer and fewer 10/100/1000 ports.
Good. Maybe that means they’ll finally upgrade the damn badge readers.
I was all prepared to explain token ring architecture, but this is way better.
The idea was one computer on the LAN would hold the “talking stick” (the token) and transmit whatever data it needed to, then pass the token off to the next computer in the ring. If a computer received the token and didn’t have anything to transmit, it’d just pass on the token. The problem would be detecting when one of the computers in the loop had gone offline or crashed and taken the token with it. After some amount of time with no traffic, some system was responsible for generating a new token and an amended turn order. Similar problems existed when a new computer wanted to get added to the rotation.
They’re not merely replacing floppies, swapping in some emulators to take over. They’re attempting to redesign and future-proof the entire system. That kind of a big deal. Oh, and it all has to run flawlessly during the transition period.
This ain’t your homelab boys.
According to the article, the other improvements are priced separately from the $212 million de-floppy-ing.
And that cost includes decades of support.
The $212 million contract includes support services from Hitachi for “20 to 25 years,” the Chronicle said.
No, the $212 million includes the entire upgrade (and 20 years of support) of the automatic train control system. The full $700 million plus is for the overall modernization of multiple systems.
Not disputing what you said — just clarifying that other upgrades are not part of the $212 mil and what is meant by “whole system”. The $212 is just to replace the floppy based system with something newer that includes a service contract.
“Beyond the floppies, though, the Muni Metro needs many more upgrades. The SFMTA plans to spend $700 million (including the $212 million Hitachi contract) to overhaul the light rail’s control system. This includes replacing the loop cable system for sending data across the servers and trains. The cables are said to be a more pressing concern than the use of floppy disks. “
Supposedly the new system is five gens ahead of the old system and would have additional features. Some would say “if it ain’t broke don’t fix it” but whatever. I’m sure it will be as fancy as upgrading to Windows 11 at that price.
5.25" floppies were obsolete for years before they even installed the system in 1998. They could have been using compact flash cards by then.
Compact flash? Nah, that was primetime for Iomega Zip Drives!
Fear the click of death!
It would have been replaced a long time ago if that was the case.
Fuck yo Zip Drives, all my homies use SyQuest
Sounds like a grift. All you need is an emulator and a disk image.
Yeah if that’s all that needed replacing. The entire system is ancient, not just the disks, like:
Much more critical than the dated use of floppy disks is the system’s loop cable, which transmits data between the central servers and the trains and, according to Roccaforte, “has less bandwidth than an old AOL dial-up modem.”
The SFMTA’s website adds:
The loop cable is fragile and easily disturbed. This makes subway maintenance more difficult. This also means the system cannot be extended outside the subway, along surface rail, where currently we don’t have automatic train control.
The loop cable and other non-floppy improvements are priced out separately according to the article.
Gee, I wonder how much this would’ve cost in the past before they kept putting it off
“If you think this is expensive now, wait for 20 years” “Not a problem, I’ll be retired by then, it’ll be someone else’s problem”
Who will carry on the knowledge of what the a:\ and b:\ drives were?
I only teach my kids about /dev/fd0
Teach your kids to play music with
cat /dev/fd0 >/dev/snd.Oh my god make it stop
The CP/M gang, of course!
wait till they hear from the 5.25" Floppy Disk lobby
Big Floppy Slams San Francisco
This is clearly a tender fail. Byte code can be emulated for a fraction on that price. And it’s a two or three man job with a rota
They’d be better off not relying on the cloud.
