2 ms·

That was the story told by SGI execs. It was also a story told by Sun execs. And it was a story told by Unisys execs. But I'm sure it is different this time aro

That was the story told by SGI execs. It was also a story told by Sun execs. And it was a story told by Unisys execs. But I'm sure it is different this time around.

gambiting 9y ago
I mean sure, in a lot of cases, yes, a normal iPad is a lot better than this super custom commercial terminal for $10k/each. But if you work in an oil refinery where you can't risk an explosion of millions of gallons of petrol, or if you run a metro system that carries hundreds of thousands of people a day, you can't be using consumer grade electronics.
- lmm 9y ago
  Running two subway lines at two nines of reliability would be better for passengers than running one line at four nines, and might well be cheaper.
  - adrianN 9y ago
    A signal failure can lead to dead passengers, so maybe you want to reconsider that statement.
    - lmm 9y ago
      Signalling is always fail-safe - as far as I can tell this is the case even when there are e.g. multiple redundant ways of detecting train presence, a failure of any one is treated as a reason to stop trains. Something like a cheap LED that burns out more frequently is not unsafe, it just means there would be more cases of trains having to stop because the signal light was out.
    - notyourday 9y ago
      If you are thinking about "verified" systems spent way too much in academia. Fundamentally, verification system is a traffic light problem. In case you do not know, the blinking yellow is "i crashed". That condition is not checked via code verification of Red/Yellow/Green state machine. It is checked via crossed green detector: a circuit that checks for a condition "green energized" on both and should that condition occur it crashes the Red/Yellow/Green state machine. That state machine will never recover until Bob shows up at a traffic box, looks to see if a sensor is dead, looks to see if box is OK and resets it by hand.
- notyourday 9y ago
  Have you heard of this company called "SpaceX"? Also, in case you do not actually know this, a metric crap load of this special electronics that NY metro uses have Windows 98 running IBMs inside. Source: Neighbor MTA grunt

That was the story told by SGI execs. It was also a story told by Sun execs. And it was a story told by Unisys execs. But I'm sure it is different this time around.

gambiting 9y ago

I mean sure, in a lot of cases, yes, a normal iPad is a lot better than this super custom commercial terminal for $10k/each. But if you work in an oil refinery where you can't risk an explosion of millions of gallons of petrol, or if you run a metro system that carries hundreds of thousands of people a day, you can't be using consumer grade electronics.

lmm 9y ago
Running two subway lines at two nines of reliability would be better for passengers than running one line at four nines, and might well be cheaper.
- adrianN 9y ago
  A signal failure can lead to dead passengers, so maybe you want to reconsider that statement.
  - lmm 9y ago
    Signalling is always fail-safe - as far as I can tell this is the case even when there are e.g. multiple redundant ways of detecting train presence, a failure of any one is treated as a reason to stop trains. Something like a cheap LED that burns out more frequently is not unsafe, it just means there would be more cases of trains having to stop because the signal light was out.
  - notyourday 9y ago
    If you are thinking about "verified" systems spent way too much in academia. Fundamentally, verification system is a traffic light problem. In case you do not know, the blinking yellow is "i crashed". That condition is not checked via code verification of Red/Yellow/Green state machine. It is checked via crossed green detector: a circuit that checks for a condition "green energized" on both and should that condition occur it crashes the Red/Yellow/Green state machine. That state machine will never recover until Bob shows up at a traffic box, looks to see if a sensor is dead, looks to see if box is OK and resets it by hand.
notyourday 9y ago
Have you heard of this company called "SpaceX"? Also, in case you do not actually know this, a metric crap load of this special electronics that NY metro uses have Windows 98 running IBMs inside. Source: Neighbor MTA grunt