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.
It’s not quite as crazy as it seems. The older/larger floppy disk formats were more reliable due to their lower track density.
There was more surface area per byte of data. The old floppy disks could be written once and read for years in harsher environments. New floppy disks we more prone to failure after a few years.
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
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.
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.
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.
“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”
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
