The problem with using 1 as a toll indicator is that it breaks universal dialing. What if I want an autodialer to always work, no matter where it is plugged in. In enlightened areas of the USA, dialing all 11 digits will always work, whether the call is local or toll. It doesn't matter if the local calling area changes, the area code is split, or the autodialer is moved to a different location, it still works. This is important when phone numbers are programmed into fax machines, laptop computers, burglar alarms, elevators, vending machines, intelligent telephones and many other devices.
1 is the country code for the NANP (North American Numbering Plan) but that isn't applicable to calls within the USA. The leading 1 in a telephone number was originally a way to route the call to a toll (long distance) switch, back when telephone switches were electro-mechanical, using relays and stepper switches. They had to keep the call-handling logic as simple as possible. Today, some areas misuse it as an indication to the caller that the call is not a local call. The one meaning that is universal, except in those areas misusing it as a toll indicator, is that a leading 1 means that the switch can expect to receive 10 more digits. This means that the switch does not have to use a timeout timer to know when the caller has finished dialing the number.
You might look for issues of Cryptologia, a journal of the history and technology of cryptography. Some of the best articles have been collected and reprinted in book form by Artech House.
Machine Cryptography and Modern Cryptanalysis
Cryptology: Machines, History, and Methods
Selections From Cryptologia: History, People & Technology
You are going to find that it is almost impossible to find a magnet strong enough to erase the disk. At work, we have a number of super heavy-duty NSA approved degaussers. They can erase the credit cards in your wallet and jam cardiac pacemakers, just by being in the same room as the degausser, but they can't erase modern hard disks and newer tape formulations. The coercivity on modern media is just too high. The media must be overwritten by the device that created it or it must be physically destroyed.
Even if you found a magnet that was strong enough to erase the data, it would also destroy the servo information on the disk platters. That would render the drive useless, since it must have the servo information to position the head on the disk. The disk drive factory is the only place that has the equipment that can write servo information on the disk platters.
AM channel spacing in North America is 10 kHz. That does not mean that AM broadcast stations are limited to 5 kHz of audio bandwidth. An AM broadcast station can use as much of their power as they want in the carrier +/- 10 kHz region. Above 10 kHz, there are rules that require that the power taper off as the distance from the carrier frequency increases. See Part 73.44 of the FCC regulations. The problem isn't with the broadcasters, it's with the crappy AM receivers that are in most cars and homes. Rather than have selectable IF bandwidth, they take the worst-case approach and chop off everything above 3 kHz.
What would be the point of that? The goal is to eject mass out of the rocket at the highest possible velocity. It doesn't matter whether it is steam or paper clips.
Part of the problem is that every time something does fail, every yahoo who has ever seen a rocket launch on TV starts whining about how NASA is a big waste of money and is incompetent.
Success is expected, failure is punished. Engineering, testing and operations budgets get slashed, and then people wonder why stupid mistakes slip through the system.
Every year, for decades, the budget shrinks and some more people die, retire or get laid off. The organization is slowly being hollowed out from within. Every time there is a reorganization, more people disappear. New hires are scarcer than hen's teeth. In many places, much of the electronic equipment is broken or out of calibration because most of the technicians were eliminated due to budget cuts.
Many of the costs of a shuttle launch are fixed costs. There is an expensive infrastructure that is needed to launch and maintain the shuttle. The problem is that when you cut the launch rate to save money, those fixed costs are spread over fewer launches. That makes it look more expensive than it really is to launch a shuttle. This is the same problem the Defense Department has when they buy an airplane. Congress cuts the number of airplanes that are built and slows down the production rate. This makes the airplane look very expensive because the research and development costs, along with the costs of keeping a production line running, are spread over fewer airplanes.
I've read reports of bad production runs of CDs at particular pressing plants that deteriorate much more quickly than normal CDs. Nothing intentional, just poor process engineering.
What is the real instruction set? The processor's user-visible instruction set may be implemented in random logic, FPGAs, microcode, traps to machine code or some combination of the above. There can be more than one level of microcode. Some processors have a writable-control-store, allowing the manufacturer and/or user to change/enlarge the processor's microcode and instruction set. Western Digital used to make a multi-chip CPU that could be a DEC LSI-11 or an UCSD Pascal p-Machine by changing the control ROMs. On an IBM mainframe, an operating system call may be implemented in machine code, microcode or hardware, depending on which model you have.
When I was in the Army, we had thermite packaged in convenient rack-sized slabs in case we needed to destroy sensitive equipment. You put the slab on top of the equipment, wired it up and got the hell out of there before it was ignited.
If you try this at home you may get prosecuted by the BATF for having unregistered/unlicensed "destructive devices".
So you could still end up in prison, even if you destroyed all of your computer hardware.
Get your hands on a microcomputer that will let you turn off the refresh on a bank of DRAM. Fill the DRAM with some recognizable data and turn off the refresh. You will be surprised at how long it takes for the data to disappear. You can see recognizable chunks of data, interspersed with garbage, in the DRAM for several minutes. If you have sophisticated equipment, there are voltage shifts in the output of the DRAM cells that last even longer.
One problem would be that a computer (PC type) is not a static load on the power supply. I read some Intel design notes on supplying power to the CPU that imposed some very nasty requirements on the CPU voltage regulators. The power drawn by the CPU can vary over a large range and change very quickly. That varying load is going to cause rapid changes in the power drawn from the main power supply. Excessively long wires between the PC and the power supply could cause all sorts of problems with voltage regulation.
It can be done. I once saw a 250 kW shortwave broadcast transmitter that used water-cooled tubes in the final amplifier section. I'm not sure what the plate voltage was on the tubes, but it was enough to ruin your day. The tubes were cooled by a water jacket. The water was kept pure enough that it didn't short out the tubes.
It didn't have anything insightful to say, made gratuitous insults towards public figures disliked by the loony left, and reduced a complex situation to a set of distorted and misleading images suitable for ingestion by the MTV generation.
Re:Atomic precision over FM? Shyeah! As if!
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Assorted CES Gizmos
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You could use a receiver that phase locks to the carrier and compares the received carrier phase to a local reference oscillator. If you know your geographic location, you can compensate for propagation delay. i've seen atomic clock based timing systems that used LF receivers to check the accuracy of the system against signals broadcast by timing and navigation services such as WWVB and Loran.
I'm not going to buy a new car until I can find one with a top speed that is an order of magnitude higher than my current car. I don't want to hear any whining about the difficulty of designing cars that are aerodynamically stable at Mach 1.2.
I was recently called up for jury duty. Besides the usual rules prohibiting weapons in the courthouse, there was a new rule that banned cell phones with the capability of recording sound, a common feature in recent models of cell phones.
It doesn't take any special qualifications to be admitted to the Bar of the Supreme Court. Get your application here. I've seen these certificates on the walls of many law offices in Washington, D.C. There are about 180,000 lawyers who are members of the Bar of the Supreme Court.
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The problem with using 1 as a toll indicator is that it breaks universal dialing. What if I want an autodialer to always work, no matter where it is plugged in. In enlightened areas of the USA, dialing all 11 digits will always work, whether the call is local or toll. It doesn't matter if the local calling area changes, the area code is split, or the autodialer is moved to a different location, it still works. This is important when phone numbers are programmed into fax machines, laptop computers, burglar alarms, elevators, vending machines, intelligent telephones and many other devices.
1 is the country code for the NANP (North American Numbering Plan) but that isn't applicable to calls within the USA. The leading 1 in a telephone number was originally a way to route the call to a toll (long distance) switch, back when telephone switches were electro-mechanical, using relays and stepper switches. They had to keep the call-handling logic as simple as possible. Today, some areas misuse it as an indication to the caller that the call is not a local call. The one meaning that is universal, except in those areas misusing it as a toll indicator, is that a leading 1 means that the switch can expect to receive 10 more digits. This means that the switch does not have to use a timeout timer to know when the caller has finished dialing the number.
Even if you found a magnet that was strong enough to erase the data, it would also destroy the servo information on the disk platters. That would render the drive useless, since it must have the servo information to position the head on the disk. The disk drive factory is the only place that has the equipment that can write servo information on the disk platters.
AM channel spacing in North America is 10 kHz. That does not mean that AM broadcast stations are limited to 5 kHz of audio bandwidth. An AM broadcast station can use as much of their power as they want in the carrier +/- 10 kHz region. Above 10 kHz, there are rules that require that the power taper off as the distance from the carrier frequency increases. See Part 73.44 of the FCC regulations. The problem isn't with the broadcasters, it's with the crappy AM receivers that are in most cars and homes. Rather than have selectable IF bandwidth, they take the worst-case approach and chop off everything above 3 kHz.
What would be the point of that? The goal is to eject mass out of the rocket at the highest possible velocity. It doesn't matter whether it is steam or paper clips.
Aerospace engineering never really recovered from the post-Apollo funding crunch. It put a huge number of engineers and technicians out on the street.
Every year, for decades, the budget shrinks and some more people die, retire or get laid off. The organization is slowly being hollowed out from within. Every time there is a reorganization, more people disappear. New hires are scarcer than hen's teeth. In many places, much of the electronic equipment is broken or out of calibration because most of the technicians were eliminated due to budget cuts.
Many of the costs of a shuttle launch are fixed costs. There is an expensive infrastructure that is needed to launch and maintain the shuttle. The problem is that when you cut the launch rate to save money, those fixed costs are spread over fewer launches. That makes it look more expensive than it really is to launch a shuttle. This is the same problem the Defense Department has when they buy an airplane. Congress cuts the number of airplanes that are built and slows down the production rate. This makes the airplane look very expensive because the research and development costs, along with the costs of keeping a production line running, are spread over fewer airplanes.
I've read reports of bad production runs of CDs at particular pressing plants that deteriorate much more quickly than normal CDs. Nothing intentional, just poor process engineering.
What is the real instruction set? The processor's user-visible instruction set may be implemented in random logic, FPGAs, microcode, traps to machine code or some combination of the above. There can be more than one level of microcode. Some processors have a writable-control-store, allowing the manufacturer and/or user to change/enlarge the processor's microcode and instruction set. Western Digital used to make a multi-chip CPU that could be a DEC LSI-11 or an UCSD Pascal p-Machine by changing the control ROMs. On an IBM mainframe, an operating system call may be implemented in machine code, microcode or hardware, depending on which model you have.
If you can't dazzle them with brilliance, baffle them with bullshit.
If you try this at home you may get prosecuted by the BATF for having unregistered/unlicensed "destructive devices". So you could still end up in prison, even if you destroyed all of your computer hardware.
Get your hands on a microcomputer that will let you turn off the refresh on a bank of DRAM. Fill the DRAM with some recognizable data and turn off the refresh. You will be surprised at how long it takes for the data to disappear. You can see recognizable chunks of data, interspersed with garbage, in the DRAM for several minutes. If you have sophisticated equipment, there are voltage shifts in the output of the DRAM cells that last even longer.
Rockets use RP-1, a purified form of kerosene. Regular kerosene has impurities that clog up parts of the rocket motor during sustained operation.
One problem would be that a computer (PC type) is not a static load on the power supply. I read some Intel design notes on supplying power to the CPU that imposed some very nasty requirements on the CPU voltage regulators. The power drawn by the CPU can vary over a large range and change very quickly. That varying load is going to cause rapid changes in the power drawn from the main power supply. Excessively long wires between the PC and the power supply could cause all sorts of problems with voltage regulation.
It can be done. I once saw a 250 kW shortwave broadcast transmitter that used water-cooled tubes in the final amplifier section. I'm not sure what the plate voltage was on the tubes, but it was enough to ruin your day. The tubes were cooled by a water jacket. The water was kept pure enough that it didn't short out the tubes.
I recognized a bit of Dave Brubeck (from "Take Five") in the video.
It didn't have anything insightful to say, made gratuitous insults towards public figures disliked by the loony left, and reduced a complex situation to a set of distorted and misleading images suitable for ingestion by the MTV generation.
John Kemeny and Thomas Kurtz, inventors of BASIC.
You could use a receiver that phase locks to the carrier and compares the received carrier phase to a local reference oscillator. If you know your geographic location, you can compensate for propagation delay. i've seen atomic clock based timing systems that used LF receivers to check the accuracy of the system against signals broadcast by timing and navigation services such as WWVB and Loran.
I'm not going to buy a new car until I can find one with a top speed that is an order of magnitude higher than my current car. I don't want to hear any whining about the difficulty of designing cars that are aerodynamically stable at Mach 1.2.
I was recently called up for jury duty. Besides the usual rules prohibiting weapons in the courthouse, there was a new rule that banned cell phones with the capability of recording sound, a common feature in recent models of cell phones.
See this page for sources of geiger counters in the UK.
It doesn't take any special qualifications to be admitted to the Bar of the Supreme Court. Get your application here. I've seen these certificates on the walls of many law offices in Washington, D.C. There are about 180,000 lawyers who are members of the Bar of the Supreme Court.