Today IGBTs (insulated gate bipolar transistors) and AC induction motors would be the alternative but I think the only advantage would be the lack of DC traction motors which require more maintenance than AC induction motors. There is nothing wrong with thyristor based motor controls in an application like this.
The linked article even mentions that this was not a design consideration. I remember the justification at the time was a more comfortable ride and knew the non-standard track width would be an ongoing expense. Kickbacks led to that design decision.
The nature of the implementation and flaw makes me think that it was programmed this way deliberately and these people are being charged are not part of the group that was suppose to take advantage of it.
You are probably American, or from another country that uses payee-initiated transfers and/or still supports cheques. In much of the world, banking is instantaneous now, with no "clearing" (payee-initiated systems) or "float" (payer-initiated systems) periods.
What is in it for the bank? How would they make money off of the float and cause insufficient funds charges?
I was mostly interested in the B-list movies Netflix had. When those got dropped and the A-list movies were restricted to other broken services, I dropped Netflix but did not see any other service as a substitute; they did not have the content I was interested in and were largely broken or had other restrictions making them unpalatable.
I see the same thing happening with various new poorly working and untrusted game networks versus Valve's Steam. GOG works but EA now restricts their games to their own useless Origin service. I considered breaking my strike against EA for Mass Effect but they made the decision easy for me by restricting it to Origin.
But where is the list of names of the managers who were *directly responsible for the deaths of the Challenger crew*? These people are guilty of **murder**. Yet we never see their names anywhere, they're just referred to as anonymous "managers".
Being just managers, like children they could not know any better so are not responsible for the results of their actions.
Sitting the SRB sections on their side for transport is not going to damage them in any way. They were designed to withstand the bending moment generated by the main engines before liftoff against the SRB hold down bolts.
After NASA changed the hold down timing to prevent damage to the launch facilities, the bending moment from the main engines was enough to damage the SRB sections before liftoff so much that they could not be straightened without bypassing the maximum force limit on the press. The Roger's report only mentioned the issue with the hydraulic press without attributing the cause of the problem.
I am very familiar with high resolution interval timing and I think that would be the way to go although there are some refinements which can be used when you can make a repetitive measurement.
The tricky part I think would be the transmitter strobe to receiver timing uncertainty caused by any digital processing of the signal. The key-fob and receiver no doubt use a lot of relatively slow synchronous logic and that is going to add massive amounts of jitter. That can be overcome but would require strobing the key-fob transmitter asynchronously to its own internal clock unless the key-fob makes its own high resolution time-interval measurement between the received signal and its own internal clock. With a repetitive measurement maybe that can all be ignored.
Alternatively whatever technique the current generation of short range integrated radar transceivers use might apply if it does not require a wide bandwidth transceiver.
No, the key-fobs already use rolling codes to prevent replay attacks.
The current problem is that it is possible to construct a two-way radio repeater to extend the distance over which the car can contact the key-fob. This same exploit can also be used against securely encrypted contactless money cards unless they require a PIN or other out of band authentication.
The tolerances might be a problem but the resolution is not; it just requires a different way of thinking.
The speed if light is about 1 nanosecond per foot implying that you need a 1 GHz counter to get to that resolution. In practice however analog interpolation easily allows single shot measurements with 2 or more orders of magnitude better resolution so only a 10 MHz counter is needed which is not difficult at all. Some of the newer PIC microcontrollers even have the hardware (CTMU or charge time measurement unit) to support this built in. I am used to discrete implementations which easily get down to 50 picoseconds. The bandwidths needed are not all that high either and 50 MHz is sufficient to get down to differences in time below 1 nanosecond.
What would be needed though is a invariant fixed delay between the strobed transmitter, reply from the key-fob, and the receiver which is likely going to require some major design changes to prevent sampling error do to their clocked digital design. The delay measurement itself is almost trivial in comparison.
The reed switch glued to the underside of my cup holder is not computer based and works to prevent operating my car just fine unless you have my magnetic coaster.
The keyfob has very little battery capacity and power available making the use of a GPS receiver impractical. And even if GPS was an option, either the car or the keyfob or both are regularly going to at least be used in areas where GPS is not available. And even if they never were, nobody is going to put up with the delay caused by the keyfob generating a GPS solution while they wait for their car.
What might work is a TDA (time domain arrival) solution where the distance between the keyfob and the car is measured or at least estimated but it will still lower the operating lifetime of the keyfob many times before it needs a new battery.
So the Feds should buy Apple for about the cost of 4 F-35s. Sounds like a deal to me but why would they do that if they can get what they want through the courts for comparatively free?
With a typical supply current of 6 milliamps and maximum of 10 milliamps, those are not suitable if battery power is used and if you have to plug it in, then you might as well synchronize to the power line frequency.
If the 1TB drive has 2 platters, then that is 4 surfaces with 250GB per surface. Removing one platter and two heads leaves 500GB of capacity. Lowering that to 314GB means either 1 platter and 2 surfaces at a lower density of 1 surface at a higher density.
You can go a step further and tell from the power specifications how many platters and sometimes heads are used despite the manufacturers leaving this information off.
Slashdot Mirror
Today IGBTs (insulated gate bipolar transistors) and AC induction motors would be the alternative but I think the only advantage would be the lack of DC traction motors which require more maintenance than AC induction motors. There is nothing wrong with thyristor based motor controls in an application like this.
The linked article even mentions that this was not a design consideration. I remember the justification at the time was a more comfortable ride and knew the non-standard track width would be an ongoing expense. Kickbacks led to that design decision.
I know of at least one counter example. Unfortunately the article does not discuss how many nuns, puppies, and legislators are shot every day.
http://www.nytimes.com/2013/03...
The nature of the implementation and flaw makes me think that it was programmed this way deliberately and these people are being charged are not part of the group that was suppose to take advantage of it.
What is in it for the bank? How would they make money off of the float and cause insufficient funds charges?
I was mostly interested in the B-list movies Netflix had. When those got dropped and the A-list movies were restricted to other broken services, I dropped Netflix but did not see any other service as a substitute; they did not have the content I was interested in and were largely broken or had other restrictions making them unpalatable.
I see the same thing happening with various new poorly working and untrusted game networks versus Valve's Steam. GOG works but EA now restricts their games to their own useless Origin service. I considered breaking my strike against EA for Mass Effect but they made the decision easy for me by restricting it to Origin.
The term "thug" was already taken.
NASA's belief that they had orders to launch no matter what were more insidious than that.
https://en.wikipedia.org/wiki/...
Being just managers, like children they could not know any better so are not responsible for the results of their actions.
Sitting the SRB sections on their side for transport is not going to damage them in any way. They were designed to withstand the bending moment generated by the main engines before liftoff against the SRB hold down bolts.
After NASA changed the hold down timing to prevent damage to the launch facilities, the bending moment from the main engines was enough to damage the SRB sections before liftoff so much that they could not be straightened without bypassing the maximum force limit on the press. The Roger's report only mentioned the issue with the hydraulic press without attributing the cause of the problem.
I am very familiar with high resolution interval timing and I think that would be the way to go although there are some refinements which can be used when you can make a repetitive measurement.
The tricky part I think would be the transmitter strobe to receiver timing uncertainty caused by any digital processing of the signal. The key-fob and receiver no doubt use a lot of relatively slow synchronous logic and that is going to add massive amounts of jitter. That can be overcome but would require strobing the key-fob transmitter asynchronously to its own internal clock unless the key-fob makes its own high resolution time-interval measurement between the received signal and its own internal clock. With a repetitive measurement maybe that can all be ignored.
Alternatively whatever technique the current generation of short range integrated radar transceivers use might apply if it does not require a wide bandwidth transceiver.
No, the key-fobs already use rolling codes to prevent replay attacks.
The current problem is that it is possible to construct a two-way radio repeater to extend the distance over which the car can contact the key-fob. This same exploit can also be used against securely encrypted contactless money cards unless they require a PIN or other out of band authentication.
The tolerances might be a problem but the resolution is not; it just requires a different way of thinking.
The speed if light is about 1 nanosecond per foot implying that you need a 1 GHz counter to get to that resolution. In practice however analog interpolation easily allows single shot measurements with 2 or more orders of magnitude better resolution so only a 10 MHz counter is needed which is not difficult at all. Some of the newer PIC microcontrollers even have the hardware (CTMU or charge time measurement unit) to support this built in. I am used to discrete implementations which easily get down to 50 picoseconds. The bandwidths needed are not all that high either and 50 MHz is sufficient to get down to differences in time below 1 nanosecond.
What would be needed though is a invariant fixed delay between the strobed transmitter, reply from the key-fob, and the receiver which is likely going to require some major design changes to prevent sampling error do to their clocked digital design. The delay measurement itself is almost trivial in comparison.
The reed switch glued to the underside of my cup holder is not computer based and works to prevent operating my car just fine unless you have my magnetic coaster.
The keyfob has very little battery capacity and power available making the use of a GPS receiver impractical. And even if GPS was an option, either the car or the keyfob or both are regularly going to at least be used in areas where GPS is not available. And even if they never were, nobody is going to put up with the delay caused by the keyfob generating a GPS solution while they wait for their car.
What might work is a TDA (time domain arrival) solution where the distance between the keyfob and the car is measured or at least estimated but it will still lower the operating lifetime of the keyfob many times before it needs a new battery.
Why wouldn't Apple be able to substantiate the cost? They would know how much time and effort went into creating the program earlier.
Or are you suggesting that the court would penalize them for destroying something they had no reason to preserve?
You have to cut the coat to fit the politician.
We need a safe disposal, err, I mean vacation spot for politicians and lawyers.
It is too bad that Apple did not design the iPhone so that updates cannot be installed without unlocking the device or erasing all content.
Are the later ones with secure enclave hardware susceptible to this? I am no longer sure.
So the Feds should buy Apple for about the cost of 4 F-35s. Sounds like a deal to me but why would they do that if they can get what they want through the courts for comparatively free?
God is on the side with the best lobbying.
SCOTUS has not ruled directly on this yet.
https://en.wikipedia.org/wiki/...
With a typical supply current of 6 milliamps and maximum of 10 milliamps, those are not suitable if battery power is used and if you have to plug it in, then you might as well synchronize to the power line frequency.
If the 1TB drive has 2 platters, then that is 4 surfaces with 250GB per surface. Removing one platter and two heads leaves 500GB of capacity. Lowering that to 314GB means either 1 platter and 2 surfaces at a lower density of 1 surface at a higher density.
You can go a step further and tell from the power specifications how many platters and sometimes heads are used despite the manufacturers leaving this information off.