Radios are infamous for local oscillator radiation. When the FM signal comes into the radio, it is mixed with a local oscillator signal to downconvert the desired signal to the first IF, usually 10.7 MHz. The local oscillator's frequency is probably set to the frequency of the station you are listening to, plus or minus 10.7 MHz. It isn't unusual for local oscillator energy to escape back up the antenna lead, or to be radiated directly from the electronic circuits.
Most of the infamous "TV detector" vans in the UK look for local oscillator radiation from TV sets. Not only can they detect that you have a television, the frequency of the local oscillator tells them which channel you are watching. The Nazis and Soviets used similar techniques to locate people who were listening to illegal foreign broadcasts.
If you look at a spectrum allocation chart, guess what is immediately above the FM broadcast band (88-108 MHz)? The aeronautical band (108-136 MHz), used for voice communication and navigation. Now imagine that you are sitting on an aircraft, listening to KRAP 106.3 MHz on your FM radio. The radio set the local oscillator to 117 MHz (106.3 + 10.7) to mix the signal down to 10.7 MHz. The FM radio is now radiating a signal in the middle of the aeronautical band, hopefully not on a frequency that the pilot is currently using. The radiation from the local oscillator may be relatively weak, but you are much closer to the aircraft's radio antenna than the control tower or the navigation beacon. This was the earliest noted form of interference from passenger electronics to aircraft electronics, well before laptops, GBAs and PDAs.
The spellchecker is a digital device. That means it uses lots of digital signals with fast transitions, similar to square waves. Square waves, and digital signals in general, have a large amount of harmonic content. That means that a 10 MHz square wave also contains substantial energy at odd harmonics of the 10 MHz fundamental frequency, such as 30 MHz and 50 MHz.
Consumer electronics devices are designed to be cheap. That means that they will not add shielding or EMI suppression unless someone holds a gun to their head.
A portable digital device can radiate large amounts of interference at many different frequencies. What is even worse, the RF output is not constant. Anything with a microprocessor in it will radiate at varying frequencies and power levels depending on what code the microprocessor is executing. This makes it almost impossible to test for interference to specific frequencies.
The earliest forms of computer music involved putting an AM radio near the computer and executing code snippets that would produce the desired sound (interference) on the radio.
They aren't tested by the FCC, they are tested by the manufacturer.
"This device may not cause harmful interference" means that if your device causes harmful interference, you are legally required to turn it off. If you want to be an asshole about it, the FCC can formally order you to stop using the device, fine you thousands of dollars, send in the U.S. Marshals to seize it, etc.
Computers Existed Before C
on
Secure Programming
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· Score: 2, Insightful
20+ years ago I used an operating system that was written in Pascal. There have been commercial operating systems written in FORTRAN, PL/I, LISP and other languages.
They might have swiped that from the PDP-11/70. It had an 8-bit display register. RSX-11M, and I assume other DEC operating systems, had a SYSGEN option that added code to the task scheduler to put a oscillating pattern in the display register.
It won't mean a damn thing if software designers and programmers don't readjust their priorities. That includes Microsoft and the open source community.
More time than I care to recall, a decision has had to be made between the right way and the fast way. The fast way almost always wins, even if it is fragile and error-prone.
Is the computing community willing to give more than lip service to security and reliability? Past history say no.
No, this doesn't have anything to do with "global warming". The Sun's output is slowly increasing as it ages. Eventually this will tip the Earth into thermal runaway. The good news is that homo sapiens will be long gone by the time it happens.
The trick is to build the power plants in the same area that the load is located in. This reduces the amount of power that must be imported or exported from any given area.
Unfortunately, some people and politicians prefer to have the generating capacity, and its associated pollution, somewhere else (see NIMBY).
Have you talked to any of the people at your local bank office lately? I've noticed that the large banks have cut costs by getting rid of older, more experienced and educated, employees. They have been replaced with cheaper employees whose skills are limited to data entry and the ability to read the policy and procedures manuals. Anything problem not listed in the manual gets kicked upstairs.
Due to a data entry error, the payee's bank presented a check to my bank for payment, with the amount of the check miscoded as 10x the actual amount written on the check. Since the funds in my checking account were insufficient to cover the check, my bank raided my savings account for the money necessary to cover the check. I only found out about it when my checks started bouncing and I got an account statement. I eventually got the bank to fix the problem and recovered all of the money that had been mistakenly paid out.
The bank officer didn't think there was anything wrong with the bank's computer taking money from one account to cover a deficit in another account. No humans were involved. It is cheaper for the bank to run everything on automatic pilot and only involve humans when there is a complaint to investigate.
It should be transparent to you. There should still be a 64 kbps full-duplex pipe between the end-points of the connection. The difference is how the bits get transported.
In a perfect world, contracts and licenses would be written in plain English, would be the product of negotiation between the parties, would be read and understood before money changed hands, would address the interests of both parties, and would not contain clauses that were unenforceable and purely included for their intimidation value.
Unfortunately, in the real world, contracts and licenses are often nothing more than a legal weapon to be used against the purchaser. They promise nothing, disclaim all liability and try to prevent the purchaser from using any of the normal legal remedies for goods that are defective or that do not perform as advertised. They are "contracts of adhesion", dictated to the purchaser by the seller, and not subject to modification.
It is unreasonable to expect the purchaser to read and understand every contract and license that is slapped on every widget or service that they purchase. Should they hire a lawyer to explain what it really means, and what clauses would get laughed out of court if the seller attempted to enforce them?
To the average person, the legal system is a tool reserved for the rich, and contracts and licenses are just another club for the powerful to use against the weak. Why even bother reading a contract or license when you know that you can't change it, you don't understand it, it probably includes bits that are legal bullshit, and the chances of you enforcing it against the seller are nil.
The question is, how much, if any, hardware and software engineering is done in-house for the Netgear products? Just because something has a company's name on the box doesn't mean that they designed or built it. This is especially true for low-end product lines. I could call up an OEM in Taiwan and, assuming I had the money, start selling Detritus brand switches and routers within a month or two, with my name on the box and everything.
Kodak did some accelerated longevity tests on CD-Rs and found that many disks degraded rapidly when exposed to sunlight, due to the UV components of sunlight.
I ran into a similar problem. Back when computers were built from TTL chips and wire-wrap boards, I found a piece of wire-wrap wire hanging from the backplane. Only one end was connected to a wire-wrap pin. The other end wasn't connected to anything. Assuming that it was a leftover from a previous field modification, I removed the wire. Bad move. The system started to randomly crash. I reinstalled the wire and the system stopped crashing.
That attitude towards ECC, and other forms of hardware error detection and correction, has led people into building supercomputers that were expensive disasters, like the ILLIAC IV. What's the point of having a fast supercomputer if you have to run a job two or three times to have some confidence in the results?
There is nothing worse than having a computer without ECC or parity memory, and trying to detect and diagnose subtle pattern sensitivity memory problems.
Besides thermal noise, you also have to consider alpha particle emissions from packaging materials and cosmic rays. There are also electrical noise issues in memory assemblies.
New TV sets are starting to be introduced with "digital cable ready" tuners. That means that they can receive digital cable channels without an external converter box. Hopefully this feature will be included in future PVRs.
When your country sits on top of vast reserves of cheap oil, you can expect other countries to be suspicious when you express a sudden interest in developing a nuclear energy program for scientific research and energy production. Scientific research can be done with research reactors, which have minimal proliferation hazards. Power production reactors make no economic sense when there are abundant supplies of cheap oil.
There is a reason all of those federal and state regulatory commissions were put in place, and it wasn't just to stab entrepreneurs in the back.
Do you want reliable telephone service? Even if there is a power failure?
Do you want guaranteed availability of telephone service at uniform and reasonable rates, even if you live on a farm or in a slum?
Do you want 911 service that works?
Besides loss of tax revenues and control, there is a good reason for regulatory agencies to be concerned about VOIP. What if VOIP severely damages the market for conventional telephone service? That could result in the loss of universal and reliable, even if somewhat overpriced, telephone service in this country.
A swish pan may be a recognized effect but it wasn't what I was referring to. I was thinking of a shot of a landscape, where everything is in sharp focus, combined with a pan that is slow enough that instead of blurring, the landscape jerks across the screen, klunk, klunk, knunk, at 24 painfully obvious frames per second.
The projector does open the shutter twice for each frame to reduce the sensation of flicker.
I read an article that said Japan has a major problem with "suicide by train". Despondent people stand on the tracks in front of an oncoming high-speed train.
You could design a game to always preserve a constant frame rate. The program would synchronize itself to vertical retrace or another periodic signal. It would have to be able to build the next frame buffer in a bounded amount of time. This might require it to drop detail or features when a lot of things were going on.
Movie projectors cheat by displaying every frame twice, which doubles the frame rate from 24 fps to 48 fps. Cinematographers also avoid certain shots, like rapidly panning from left to right, which look terrible on a movie screen.
It's an issue of national security. There are many countries that would not issue any amateur licenses if encryption was allowed. Although they have more modern toys today, the stereotypical spy used a hidden transmitter to send his reports back to his case officer in encrypted morse code. Amateur radio was shut down completely during World War II due to concerns about espionage. Even today, the more paranoid countries restrict amateur radio to club stations that can be easily monitored for subversive activities. In the worst cases, amateur radio is prohibited and unauthorized possession of radio equipment is considered proof of espionage, resulting in death or imprisonment.
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Most of the infamous "TV detector" vans in the UK look for local oscillator radiation from TV sets. Not only can they detect that you have a television, the frequency of the local oscillator tells them which channel you are watching. The Nazis and Soviets used similar techniques to locate people who were listening to illegal foreign broadcasts.
If you look at a spectrum allocation chart, guess what is immediately above the FM broadcast band (88-108 MHz)? The aeronautical band (108-136 MHz), used for voice communication and navigation. Now imagine that you are sitting on an aircraft, listening to KRAP 106.3 MHz on your FM radio. The radio set the local oscillator to 117 MHz (106.3 + 10.7) to mix the signal down to 10.7 MHz. The FM radio is now radiating a signal in the middle of the aeronautical band, hopefully not on a frequency that the pilot is currently using. The radiation from the local oscillator may be relatively weak, but you are much closer to the aircraft's radio antenna than the control tower or the navigation beacon. This was the earliest noted form of interference from passenger electronics to aircraft electronics, well before laptops, GBAs and PDAs.
Consumer electronics devices are designed to be cheap. That means that they will not add shielding or EMI suppression unless someone holds a gun to their head.
A portable digital device can radiate large amounts of interference at many different frequencies. What is even worse, the RF output is not constant. Anything with a microprocessor in it will radiate at varying frequencies and power levels depending on what code the microprocessor is executing. This makes it almost impossible to test for interference to specific frequencies.
The earliest forms of computer music involved putting an AM radio near the computer and executing code snippets that would produce the desired sound (interference) on the radio.
"This device may not cause harmful interference" means that if your device causes harmful interference, you are legally required to turn it off. If you want to be an asshole about it, the FCC can formally order you to stop using the device, fine you thousands of dollars, send in the U.S. Marshals to seize it, etc.
20+ years ago I used an operating system that was written in Pascal. There have been commercial operating systems written in FORTRAN, PL/I, LISP and other languages.
They might have swiped that from the PDP-11/70. It had an 8-bit display register. RSX-11M, and I assume other DEC operating systems, had a SYSGEN option that added code to the task scheduler to put a oscillating pattern in the display register.
Solar flares were a serious concern to the Apollo astronauts, who were at risk while traveling to the Moon.
More time than I care to recall, a decision has had to be made between the right way and the fast way. The fast way almost always wins, even if it is fragile and error-prone.
Is the computing community willing to give more than lip service to security and reliability? Past history say no.
No, this doesn't have anything to do with "global warming". The Sun's output is slowly increasing as it ages. Eventually this will tip the Earth into thermal runaway. The good news is that homo sapiens will be long gone by the time it happens.
The trick is to build the power plants in the same area that the load is located in. This reduces the amount of power that must be imported or exported from any given area. Unfortunately, some people and politicians prefer to have the generating capacity, and its associated pollution, somewhere else (see NIMBY).
Have you talked to any of the people at your local bank office lately? I've noticed that the large banks have cut costs by getting rid of older, more experienced and educated, employees. They have been replaced with cheaper employees whose skills are limited to data entry and the ability to read the policy and procedures manuals. Anything problem not listed in the manual gets kicked upstairs.
Due to a data entry error, the payee's bank presented a check to my bank for payment, with the amount of the check miscoded as 10x the actual amount written on the check. Since the funds in my checking account were insufficient to cover the check, my bank raided my savings account for the money necessary to cover the check. I only found out about it when my checks started bouncing and I got an account statement. I eventually got the bank to fix the problem and recovered all of the money that had been mistakenly paid out.
The bank officer didn't think there was anything wrong with the bank's computer taking money from one account to cover a deficit in another account. No humans were involved. It is cheaper for the bank to run everything on automatic pilot and only involve humans when there is a complaint to investigate.
It should be transparent to you. There should still be a 64 kbps full-duplex pipe between the end-points of the connection. The difference is how the bits get transported.
Unfortunately, in the real world, contracts and licenses are often nothing more than a legal weapon to be used against the purchaser. They promise nothing, disclaim all liability and try to prevent the purchaser from using any of the normal legal remedies for goods that are defective or that do not perform as advertised. They are "contracts of adhesion", dictated to the purchaser by the seller, and not subject to modification.
It is unreasonable to expect the purchaser to read and understand every contract and license that is slapped on every widget or service that they purchase. Should they hire a lawyer to explain what it really means, and what clauses would get laughed out of court if the seller attempted to enforce them?
To the average person, the legal system is a tool reserved for the rich, and contracts and licenses are just another club for the powerful to use against the weak. Why even bother reading a contract or license when you know that you can't change it, you don't understand it, it probably includes bits that are legal bullshit, and the chances of you enforcing it against the seller are nil.
The question is, how much, if any, hardware and software engineering is done in-house for the Netgear products? Just because something has a company's name on the box doesn't mean that they designed or built it. This is especially true for low-end product lines. I could call up an OEM in Taiwan and, assuming I had the money, start selling Detritus brand switches and routers within a month or two, with my name on the box and everything.
Kodak did some accelerated longevity tests on CD-Rs and found that many disks degraded rapidly when exposed to sunlight, due to the UV components of sunlight.
I ran into a similar problem. Back when computers were built from TTL chips and wire-wrap boards, I found a piece of wire-wrap wire hanging from the backplane. Only one end was connected to a wire-wrap pin. The other end wasn't connected to anything. Assuming that it was a leftover from a previous field modification, I removed the wire. Bad move. The system started to randomly crash. I reinstalled the wire and the system stopped crashing.
There is nothing worse than having a computer without ECC or parity memory, and trying to detect and diagnose subtle pattern sensitivity memory problems.
Besides thermal noise, you also have to consider alpha particle emissions from packaging materials and cosmic rays. There are also electrical noise issues in memory assemblies.
New TV sets are starting to be introduced with "digital cable ready" tuners. That means that they can receive digital cable channels without an external converter box. Hopefully this feature will be included in future PVRs.
When your country sits on top of vast reserves of cheap oil, you can expect other countries to be suspicious when you express a sudden interest in developing a nuclear energy program for scientific research and energy production. Scientific research can be done with research reactors, which have minimal proliferation hazards. Power production reactors make no economic sense when there are abundant supplies of cheap oil.
Do you want reliable telephone service? Even if there is a power failure?
Do you want guaranteed availability of telephone service at uniform and reasonable rates, even if you live on a farm or in a slum?
Do you want 911 service that works?
Besides loss of tax revenues and control, there is a good reason for regulatory agencies to be concerned about VOIP. What if VOIP severely damages the market for conventional telephone service? That could result in the loss of universal and reliable, even if somewhat overpriced, telephone service in this country.
The projector does open the shutter twice for each frame to reduce the sensation of flicker.
I read an article that said Japan has a major problem with "suicide by train". Despondent people stand on the tracks in front of an oncoming high-speed train.
You could design a game to always preserve a constant frame rate. The program would synchronize itself to vertical retrace or another periodic signal. It would have to be able to build the next frame buffer in a bounded amount of time. This might require it to drop detail or features when a lot of things were going on.
Movie projectors cheat by displaying every frame twice, which doubles the frame rate from 24 fps to 48 fps. Cinematographers also avoid certain shots, like rapidly panning from left to right, which look terrible on a movie screen.
It's an issue of national security. There are many countries that would not issue any amateur licenses if encryption was allowed. Although they have more modern toys today, the stereotypical spy used a hidden transmitter to send his reports back to his case officer in encrypted morse code. Amateur radio was shut down completely during World War II due to concerns about espionage. Even today, the more paranoid countries restrict amateur radio to club stations that can be easily monitored for subversive activities. In the worst cases, amateur radio is prohibited and unauthorized possession of radio equipment is considered proof of espionage, resulting in death or imprisonment.