Mostly two way, although there are some one way propagation beacons.
Is ham all private or is it also commercial?
Commercial traffic is prohibited.
Is ham radio sort of like a bbs type community?
There are bulletin boards that you can access via packet radio (radio modems).
Do you meet new people on ham radio or talk to ones you meat in real life?
You meet lots of new people, esp. on the HF (high frequency) bands.
What kind of transmit ranges are possible?
You can cover the Earth with an HF (3-30 MHz) radio. VHF and higher frequencies are generally limited to line-of-sight, just like broadcast FM radio. There are amateur satellites that can extend the range of VHF/UHF stations.
Unfortunately, the FCC did not automatically upgrade Tech Plus licenses to General. You have to wait until April and file some paperwork.
When I took the test for a Technician license, I had to pass a 5 WPM code test and the General written test. That is the same as the new requirements for the General license.
I've never bothered upgrading since I got a Technician license. I could easily pass the written test but I hate morse code. Now I might try for an Extra license.
The biggest threat is going to be from lunatics who are going to assume that bank alarms etc. won't work and go out and act like juvenile delinquents on halloween.
If I was going to rob a bank, this would be the time to do it. Assuming that the police would be tied up with other problems.
Numerous problems showed up in the USA when they first started issuing credit cards with 2000 expiration dates. VISA and Mastercard spent a great deal of time and money on fixing the problem. Many of the credit card validation terminals were broken and had to be upgraded or replaced, not to mention the software in the banks.
I used to enjoy reading the source code for DEC device drivers. The programmers always seemed to assume the worst from the hardware. They would set up timers so that if the controller went catatonic, they could reset it and retry the request. Some of the Unix source code that I have read took the opposite approach, error recovery consisted of calling panic(). The rumor was that DEC used to burn in VAX systems by running Unix, since it would crash on systems with hardware glitches that wouldn't bother VMS.
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A process that's stuck waiting on I/O (which sounds like what you're describing) will not be killable on any Unix or Unix-like OS.
There is a interruptable flag in the arguments to the sleep() kernel routine that determines whether or not a process can be killed when it is blocked on an event. That makes it driver dependent.
I used to have problems with an old 68000 Unix system's tty driver, the serial chip would get confused and processes would go into an unkillable state waiting for certain events. Later releases of the kernel fixed the problem by adding the interruptable flag to the sleep() calls in the tty driver.
At least the interrupts and DMA channels worked. My company had major problems with Apple IIs that were being used for data acquisition. Our I/O cards used interrupts and we found that interrupts didn't work properly in many of the computers. It appeared that Apple didn't test all of the features on their boards during manufacture, just the one that were commonly used.
Just because they say the warranty is void if the seals are broken, doesn't make it true. You may have to take them to small claims court if they insist on being jerks about it. The same thing applies to warranty registration cards, you have a warranty whether or not you mail the card.
If my auto mechanic screws up, I might get stranded when the car dies. A pain in the neck, but not a major disaster.
If my aircraft mechanic screws up, there is a good chance that my passengers and I will be killed or seriously injured, not to mention the danger to people on the ground.
I like having the FAA around to certify aircraft mechanics and to make sure that aircraft replacement parts meet the aircraft manufacturer's specifications. Even with the FAA, there have been problems with counterfeit parts getting into the supply chain.
But the internet isn't the only problem with the perscription drug system. Even if all doctors are honest, I can:
1. Attempt to impersonate a nurse calling in a perscription.
2. Take a perscription form and write what I want down on it.
One of my relatives is a pharmacist. She is quite good at detecting bogus prescriptions. The typical case is an individual who walks into the pharmacy, looking like a junky, with a badly forged prescription for a highly abusable drug. They usually disappear as soon as she picks up the telephone. Certain drugs must be prescribed on special, numbered prescription forms. If anything is questionable, the pharmacist calls the doctor to verify the prescription. A more common problem is old doctors who will write prescriptions for a fee. They don't care if they lose their license since they were going to retire anyway.
Finally, this is MILSPEC we're dealing with. MILSPEC leaves absolutely nothing to chance. That is why you see such unimportant information as UDMA66 and the Intellimouse in the spec list. Why was it specified? Because it could be. The military is quite anal about things like that, and whether it's liked or not, everyone in the system has to play that game.
The problem is that government procurements over X dollars are put out for competitive bidding, unless you can write a convincing sole source justification. Anything that isn't fully specified is an opportunity for a sleazy vendor to substitite some cheap piece of crap or to omit the feature. Some vendors will try to slip in obsolete or substandard hardware in order to clean out the junk from their warehouse and to make a few extra bucks. After being burned a few times, you learn how to write a specification that straitjackets the vendor into delivering what you want.
The PC is irrelevant. If someone had nuked Boca Raton, we would all be using some other cheap, microprocessor based computer. Whether it used a Pentium, PPC or SPARC.
I would make the same argument about Windows. Microsoft did not invent the GUI and there are plenty of operating systems that could have replaced it.
BSD Unix is the true starting point of the Internet as it exists today. The Unix part is not important, what matters is the BSD networking software. That was the base that enabled TCP/IP to spread across the computing world, either by emulation or by porting the code to other systems. The BSD code was the basis for the networking stacks of a wide variety of operating systems.
Take a look at the Kodak box, any Kodak box made in the last 30 years or more, and you'll see they are not liable for more than replacement of the blank film.
That assertion may be printed on the box but that doesn't mean that Kodak has no liability for consequential damages. That is a question for a court to decide. It is common to see blanket disclaimers of liability and other statements that conflict with the law on licenses, contracts, sales receipts, warranties and product packaging.
In 1919, an expedition by the Royal Society of London confirmed Einstein's prediction of the degree of deflection of light passing by the Sun during a solar eclipse.
I think Time wimped out. As much as I admire Einstein, I would argue that Hitler and Stalin had a larger influence on the modern world. We still haven't finished cleaning up all of the problems created by World War II and it's aftermath.
Their breakthrough employs a mathematical transformation of the Schrödinger wave equation that makes it possible to treat the outgoing particles not as if their wave functions extend to infinity -- as they must be treated conventionally -- but instead as if they simply vanish at large distances from the nucleus.
I'm confused by this, how did they find an exact solution to the scattering problem if they are using a finite version of the wave function? Wouldn't that be an approximation of the true wave function, which extends to infinity?
Hard disks have cooling and reliability problems when used at high altitudes, such as at astronomical observatories in Chile. I don't think they would last long on a spacecraft.
The Shuttle GPCs are not 80186s, they are IBM AP-101S computers, which replaced the IBM AP-101B computers. The IBM AP-101 is a member of the IBM 360/370 family of computers and is programmed in HAL/S.
There are two programs, PASS (primary avionics software system) and BFS (backup flight system). PASS runs on 4 computers and BFS runs on 1 computer. They were developed by two separate groups, IBM (PASS) and Rockwell (BFS). If PASS fails due to hardware or software problems, BFS can be used to fly the Shuttle.
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Mostly two way, although there are some one way propagation beacons.
Is ham all private or is it also commercial?
Commercial traffic is prohibited.
Is ham radio sort of like a bbs type community?
There are bulletin boards that you can access via packet radio (radio modems).
Do you meet new people on ham radio or talk to ones you meat in real life?
You meet lots of new people, esp. on the HF (high frequency) bands.
What kind of transmit ranges are possible?
You can cover the Earth with an HF (3-30 MHz) radio. VHF and higher frequencies are generally limited to line-of-sight, just like broadcast FM radio. There are amateur satellites that can extend the range of VHF/UHF stations.
Some hams think that a morse code requirement keeps out the riff-raff (CB'ers and the like).
The validity of the morse code requirement is one of usenet's longest running flame wars on the amateur radio newsgroups.
When I took the test for a Technician license, I had to pass a 5 WPM code test and the General written test. That is the same as the new requirements for the General license.
I've never bothered upgrading since I got a Technician license. I could easily pass the written test but I hate morse code. Now I might try for an Extra license.
If I was going to rob a bank, this would be the time to do it. Assuming that the police would be tied up with other problems.
Numerous problems showed up in the USA when they first started issuing credit cards with 2000 expiration dates. VISA and Mastercard spent a great deal of time and money on fixing the problem. Many of the credit card validation terminals were broken and had to be upgraded or replaced, not to mention the software in the banks.
The frogs^H^H^H^H^HInternational Earth Rotation Service (IERS) controls UTC.
Because programmers are interested in details/trivia and they are human.
I wish I had a dollar for every incorrect description of the leap year rules that has been posted on the Internet.
Leap year bugs are distressingly common in computer software.
DEC wrote an amusing SPR response on the subject.
I used to enjoy reading the source code for DEC device drivers. The programmers always seemed to assume the worst from the hardware. They would set up timers so that if the controller went catatonic, they could reset it and retry the request. Some of the Unix source code that I have read took the opposite approach, error recovery consisted of calling panic(). The rumor was that DEC used to burn in VAX systems by running Unix, since it would crash on systems with hardware glitches that wouldn't bother VMS.
There is a interruptable flag in the arguments to the sleep() kernel routine that determines whether or not a process can be killed when it is blocked on an event. That makes it driver dependent.
I used to have problems with an old 68000 Unix system's tty driver, the serial chip would get confused and processes would go into an unkillable state waiting for certain events. Later releases of the kernel fixed the problem by adding the interruptable flag to the sleep() calls in the tty driver.
At least the interrupts and DMA channels worked. My company had major problems with Apple IIs that were being used for data acquisition. Our I/O cards used interrupts and we found that interrupts didn't work properly in many of the computers. It appeared that Apple didn't test all of the features on their boards during manufacture, just the one that were commonly used.
IBM had a 68000 based computer, I think it was from the laboratory systems division. Sort of an early attempt at a technical workstation.
Just because they say the warranty is void if the seals are broken, doesn't make it true. You may have to take them to small claims court if they insist on being jerks about it. The same thing applies to warranty registration cards, you have a warranty whether or not you mail the card.
I represent the National Weasel Association. My clients are unhappy about being compared to lawyers and are considering court action.
If my aircraft mechanic screws up, there is a good chance that my passengers and I will be killed or seriously injured, not to mention the danger to people on the ground.
I like having the FAA around to certify aircraft mechanics and to make sure that aircraft replacement parts meet the aircraft manufacturer's specifications. Even with the FAA, there have been problems with counterfeit parts getting into the supply chain.
1. Attempt to impersonate a nurse calling in a perscription.
2. Take a perscription form and write what I want down on it.
One of my relatives is a pharmacist. She is quite good at detecting bogus prescriptions. The typical case is an individual who walks into the pharmacy, looking like a junky, with a badly forged prescription for a highly abusable drug. They usually disappear as soon as she picks up the telephone. Certain drugs must be prescribed on special, numbered prescription forms. If anything is questionable, the pharmacist calls the doctor to verify the prescription. A more common problem is old doctors who will write prescriptions for a fee. They don't care if they lose their license since they were going to retire anyway.
The problem is that government procurements over X dollars are put out for competitive bidding, unless you can write a convincing sole source justification. Anything that isn't fully specified is an opportunity for a sleazy vendor to substitite some cheap piece of crap or to omit the feature. Some vendors will try to slip in obsolete or substandard hardware in order to clean out the junk from their warehouse and to make a few extra bucks. After being burned a few times, you learn how to write a specification that straitjackets the vendor into delivering what you want.
I would make the same argument about Windows. Microsoft did not invent the GUI and there are plenty of operating systems that could have replaced it.
BSD Unix is the true starting point of the Internet as it exists today. The Unix part is not important, what matters is the BSD networking software. That was the base that enabled TCP/IP to spread across the computing world, either by emulation or by porting the code to other systems. The BSD code was the basis for the networking stacks of a wide variety of operating systems.
That assertion may be printed on the box but that doesn't mean that Kodak has no liability for consequential damages. That is a question for a court to decide. It is common to see blanket disclaimers of liability and other statements that conflict with the law on licenses, contracts, sales receipts, warranties and product packaging.
Edison is sometimes credited as the inventor of the modern research laboratory.
In 1919, an expedition by the Royal Society of London confirmed Einstein's prediction of the degree of deflection of light passing by the Sun during a solar eclipse.
I think Time wimped out. As much as I admire Einstein, I would argue that Hitler and Stalin had a larger influence on the modern world. We still haven't finished cleaning up all of the problems created by World War II and it's aftermath.
What about Einstein's work on the photoelectric effect? The photoelectric effect was not explainable by classical physics.
I'm confused by this, how did they find an exact solution to the scattering problem if they are using a finite version of the wave function? Wouldn't that be an approximation of the true wave function, which extends to infinity?
Hard disks have cooling and reliability problems when used at high altitudes, such as at astronomical observatories in Chile. I don't think they would last long on a spacecraft.
There are two programs, PASS (primary avionics software system) and BFS (backup flight system). PASS runs on 4 computers and BFS runs on 1 computer. They were developed by two separate groups, IBM (PASS) and Rockwell (BFS). If PASS fails due to hardware or software problems, BFS can be used to fly the Shuttle.