There are three classes of acoustic products:
Sound absorbtion and damping (air) - this is foam. It takes air born sound waves, absorbs them (as in _not_ reflecting), and converts them to heat (very little heat)
Sound absorbtion and damping (solid) - this is dynamat. It takes sound waves traveling through a solid and damps them into heat. Kills vibrations on metal parts. Has an indirect effect on airborn sound by damping noise that is absorbed by the solid and would have otherwise been retransmitted (eg kills road noise in your car).
Sound blocking - eg homosote. Prevents sound waves on one side from traveling to the other. May reflect a lot of sound if not used in conjunction with an absorbative material.
The bits of data that make up your private porn collection are pretty unimportant. If they were lost, the world wouldn't even bat an eye.
The "bits" that make up a national election are quite different. Just think; the collection of each "bit" required someone to take half a day off of work, drive to a polling place, and vote.
So yes, they should back them up to paper. Back them up to clay tablets if you have to.
Really? I thought the secret fridge ad was hilarious. The rest of the ads were boring and unmemorable. I guess I just like the idea of a fridge full of beer poping out of the wall. Or that the dude was getting ripped off. I dunno. It was funny on a few different levels.
You are referring to the infamous Po-210 issue that IBM had. It actually originated from a faulty bottle-washing machine for one of the acids used in the fab process. The machine was using Po-210 to ionize a jet of air and there was a busted seal that was leaking Po-210 into the empty bottles. It took them years and millions of dollars to figure out what was going wrong.
All chips have problems with soft errors, but when there is a problem in your fab and you put a highly radioactive isotope directly into the packaging... well soft errors become a nightmare. If contaminants are well controlled, then the primary soft error source is cosmic high energy neutrons. It's a bigger deal at higher elevations, and even worse in aircraft.
If you find such things interesting, check out the references at the end of my thesis:
http://www.pdos.lcs.mit.edu/papers/softecc:ddopson -meng/softecc_ddopson-meng.pdf
Especially IBM's summary of their soft-error experience from 78-94
http://www.research.ibm.com/journal/rd/401/tocpdf. html
There is another interesting concept here: low speed, stop-and-go driving (heavy, heavy traffic). Gas engines are terribly inefficient at stop and go driving. Instead, use the gas engine to drive the alternator. Use the alternator current to drive the electric motors. Surround the electric motors in a feedback loop based on the radar/visual/whatever range to the car in front of you.
The net result would be a car that had an uber-smooth "cruise-control"-like mode for bumper-to-bumper traffic. Hit a spot of traffic at the interstate interchange? Kick your feet up and relax as your car automatically paces the car in front of you. The acceleration and "braking" would be so gentle you would barely feel it. Heck, with cars now-a-days, you could probably watch a DVD while you waited.
I see the network appliance as being tied to Flash (the nonvolitile RAM, not the craptastic web tech). Hard drives are still the big drag on most computers. Imagine a single board that had a CPU, DRAM, and Flash, all soldered on. No moving parts, low heat, no noise.
It doesn't have to be a traditional network appliance either. Simply an access point that connects to CAT-5e on one side and DVI on the other, with a mouse and KB in the middle. How much executable code runs locally vs on a server some where (and on _which_ server) isn't so important. What is important is that the endpoint device is expendable. I can yank it out and toss it in the lake, buy a new one and be up and running again. All the settings I care about replicate back and forth seamlessly.
(crap, no formatting... reposting)
Yes, there is one of the major challenges of both RAMjets and SCRAMjets. There is actually a whole range of technologies designed for different speed and air density regimes
Turbo-Props (propeller driven by jet like turbine power) is good up to a few hundred mph. Then the tips of the prop start going supersonic and cavitating. Highest efficiency
Turbo-Fan (same turbo jet power like a turbo-prop, but with an enclosed fan rather than a prop. Most of thrust still comes from the air driven by the fan. think 747) is capable of working in a faster regime up to somewhere near sonic speed (~780mph). Used for most commercial aviation because it is still fairly efficient, but faster than turboprop.
Turbo-Jet (same turbo jet power as turbo-prop, but little or no "bypass" air. The main purpose of the intake fan is now to pressurize air at intake for combustion with jet fuel. Thrust comes from) can provide substantial power at high velocites. TurboJets are the big muscular loud as hell engines used on fighter planes. They are several times less efficient than the TurboFans used in commercial airliners, but they produce many times more thrust and can run well in super-sonic regimes. More power + less efficiency = burns lots of fuel. Fighters can chew through thousands of gallons of jet fuel each hour just cruising. Temperature (melting point of metal) is a huge limit to the perf of these engines. Afterburners burn even more fuel in a way that isn't as temperature constrained, but is even less efficient. Modern fighters can burn through their fuel in something like a half hour of combat.
RAMjets work by using a constriction at the intake (rather than a fan) to pressurize the air. RAMjets don't work at low speeds, and are better designed to operate at a single design point. They typically run in the low mach numbers, although to operate, the intake air must be slowed to subsonic speeds. They are fast and efficient, but not very flexible. Typically used on missiles (due to their tendancy to operate in a single regime).
SCRAMjets are the same basic idea as a RAMjet, but the intake air remains supersonic.
Rockets do not burn any atmospheric O2 at all. For this reason, they operate equally well (or poor) at all speeds and air densities, providing a consistent predictable thrust. Due to the need to carry O2 around (which is far heavier than most of the fuels), their efficiency is appalling when compared to air-breathing engines. The uber-efficient space shuttle engines (2H2 + O2 -> 2H2O) have a specific impulse of ~440s. Solid rockets are more like ~200s. Kerosene rockets are in between. Air-breathing engines are in the thousands.
Yes, there is one of the major challenges of both RAMjets and SCRAMjets. There is actually a whole range of technologies designed for different speed and air density regimes
Turbo-Props (propeller driven by jet like turbine power) is good up to a few hundred mph. Then the tips of the prop start going supersonic and cavitating. Highest efficiency
Turbo-Fan (same turbo jet power like a turbo-prop, but with an enclosed fan rather than a prop. Most of thrust still comes from the air driven by the fan. think 747) is capable of working in a faster regime up to somewhere near sonic speed (~780mph). Used for most commercial aviation because it is still fairly efficient, but faster than turboprop.
Turbo-Jet (same turbo jet power as turbo-prop, but little or no "bypass" air. The main purpose of the intake fan is now to pressurize air at intake for combustion with jet fuel. Thrust comes from) can provide substantial power at high velocites. TurboJets are the big muscular loud as hell engines used on fighter planes. They are several times less efficient than the TurboFans used in commercial airliners, but they produce many times more thrust and can run well in super-sonic regimes. More power + less efficiency = burns lots of fuel. Fighters can chew through thousands of gallons of jet fuel each hour just cruising. Temperature (melting point of metal) is a huge limit to the perf of these engines. Afterburners burn even more fuel in a way that isn't as temperature constrained, but is even less efficient. Modern fighters can burn through their fuel in something like a half hour of combat.
RAMjets work by using a constriction at the intake (rather than a fan) to pressurize the air. RAMjets don't work at low speeds, and are better designed to operate at a single design point. They typically run in the low mach numbers, although to operate, the intake air must be slowed to subsonic speeds. They are fast and efficient, but not very flexible. Typically used on missiles (due to their tendancy to operate in a single regime).
SCRAMjets are the same basic idea as a RAMjet, but the intake air remains supersonic.
Rockets do not burn any atmospheric O2 at all. For this reason, they operate equally well (or poor) at all speeds and air densities, providing a consistent predictable thrust. Due to the need to carry O2 around (which is far heavier than most of the fuels), their efficiency is appalling when compared to air-breathing engines. The uber-efficient space shuttle engines (2H2 + O2 -> 2H2O) have a specific impulse of ~440s. Solid rockets are more like ~200s. Kerosene rockets are in between. Air-breathing engines are in the thousands.
Slashdot Mirror
Don't forget Terminal Server CAL's. My team has to make money too!
There are three classes of acoustic products: Sound absorbtion and damping (air) - this is foam. It takes air born sound waves, absorbs them (as in _not_ reflecting), and converts them to heat (very little heat) Sound absorbtion and damping (solid) - this is dynamat. It takes sound waves traveling through a solid and damps them into heat. Kills vibrations on metal parts. Has an indirect effect on airborn sound by damping noise that is absorbed by the solid and would have otherwise been retransmitted (eg kills road noise in your car). Sound blocking - eg homosote. Prevents sound waves on one side from traveling to the other. May reflect a lot of sound if not used in conjunction with an absorbative material.
The bits of data that make up your private porn collection are pretty unimportant. If they were lost, the world wouldn't even bat an eye. The "bits" that make up a national election are quite different. Just think; the collection of each "bit" required someone to take half a day off of work, drive to a polling place, and vote. So yes, they should back them up to paper. Back them up to clay tablets if you have to.
Really? I thought the secret fridge ad was hilarious. The rest of the ads were boring and unmemorable. I guess I just like the idea of a fridge full of beer poping out of the wall. Or that the dude was getting ripped off. I dunno. It was funny on a few different levels.
You are referring to the infamous Po-210 issue that IBM had. It actually originated from a faulty bottle-washing machine for one of the acids used in the fab process. The machine was using Po-210 to ionize a jet of air and there was a busted seal that was leaking Po-210 into the empty bottles. It took them years and millions of dollars to figure out what was going wrong. All chips have problems with soft errors, but when there is a problem in your fab and you put a highly radioactive isotope directly into the packaging... well soft errors become a nightmare. If contaminants are well controlled, then the primary soft error source is cosmic high energy neutrons. It's a bigger deal at higher elevations, and even worse in aircraft. If you find such things interesting, check out the references at the end of my thesis: http://www.pdos.lcs.mit.edu/papers/softecc:ddopson -meng/softecc_ddopson-meng.pdf
Especially IBM's summary of their soft-error experience from 78-94
http://www.research.ibm.com/journal/rd/401/tocpdf. html
Plutonium works better. Larger fission cross-section. But they're both more fun when their friends deuterium and tritium join the party.
There is another interesting concept here: low speed, stop-and-go driving (heavy, heavy traffic). Gas engines are terribly inefficient at stop and go driving. Instead, use the gas engine to drive the alternator. Use the alternator current to drive the electric motors. Surround the electric motors in a feedback loop based on the radar/visual/whatever range to the car in front of you.
The net result would be a car that had an uber-smooth "cruise-control"-like mode for bumper-to-bumper traffic. Hit a spot of traffic at the interstate interchange? Kick your feet up and relax as your car automatically paces the car in front of you. The acceleration and "braking" would be so gentle you would barely feel it. Heck, with cars now-a-days, you could probably watch a DVD while you waited.
I think you missed the ironic sarcasm latent in your parent's post.
It doesn't have to be a traditional network appliance either. Simply an access point that connects to CAT-5e on one side and DVI on the other, with a mouse and KB in the middle. How much executable code runs locally vs on a server some where (and on _which_ server) isn't so important. What is important is that the endpoint device is expendable. I can yank it out and toss it in the lake, buy a new one and be up and running again. All the settings I care about replicate back and forth seamlessly.
Turbo-Props (propeller driven by jet like turbine power) is good up to a few hundred mph. Then the tips of the prop start going supersonic and cavitating. Highest efficiency
Turbo-Fan (same turbo jet power like a turbo-prop, but with an enclosed fan rather than a prop. Most of thrust still comes from the air driven by the fan. think 747) is capable of working in a faster regime up to somewhere near sonic speed (~780mph). Used for most commercial aviation because it is still fairly efficient, but faster than turboprop.
Turbo-Jet (same turbo jet power as turbo-prop, but little or no "bypass" air. The main purpose of the intake fan is now to pressurize air at intake for combustion with jet fuel. Thrust comes from) can provide substantial power at high velocites. TurboJets are the big muscular loud as hell engines used on fighter planes. They are several times less efficient than the TurboFans used in commercial airliners, but they produce many times more thrust and can run well in super-sonic regimes. More power + less efficiency = burns lots of fuel. Fighters can chew through thousands of gallons of jet fuel each hour just cruising. Temperature (melting point of metal) is a huge limit to the perf of these engines. Afterburners burn even more fuel in a way that isn't as temperature constrained, but is even less efficient. Modern fighters can burn through their fuel in something like a half hour of combat.
RAMjets work by using a constriction at the intake (rather than a fan) to pressurize the air. RAMjets don't work at low speeds, and are better designed to operate at a single design point. They typically run in the low mach numbers, although to operate, the intake air must be slowed to subsonic speeds. They are fast and efficient, but not very flexible. Typically used on missiles (due to their tendancy to operate in a single regime).
SCRAMjets are the same basic idea as a RAMjet, but the intake air remains supersonic.
Rockets do not burn any atmospheric O2 at all. For this reason, they operate equally well (or poor) at all speeds and air densities, providing a consistent predictable thrust. Due to the need to carry O2 around (which is far heavier than most of the fuels), their efficiency is appalling when compared to air-breathing engines. The uber-efficient space shuttle engines (2H2 + O2 -> 2H2O) have a specific impulse of ~440s. Solid rockets are more like ~200s. Kerosene rockets are in between. Air-breathing engines are in the thousands.
Yes, there is one of the major challenges of both RAMjets and SCRAMjets. There is actually a whole range of technologies designed for different speed and air density regimes Turbo-Props (propeller driven by jet like turbine power) is good up to a few hundred mph. Then the tips of the prop start going supersonic and cavitating. Highest efficiency Turbo-Fan (same turbo jet power like a turbo-prop, but with an enclosed fan rather than a prop. Most of thrust still comes from the air driven by the fan. think 747) is capable of working in a faster regime up to somewhere near sonic speed (~780mph). Used for most commercial aviation because it is still fairly efficient, but faster than turboprop. Turbo-Jet (same turbo jet power as turbo-prop, but little or no "bypass" air. The main purpose of the intake fan is now to pressurize air at intake for combustion with jet fuel. Thrust comes from) can provide substantial power at high velocites. TurboJets are the big muscular loud as hell engines used on fighter planes. They are several times less efficient than the TurboFans used in commercial airliners, but they produce many times more thrust and can run well in super-sonic regimes. More power + less efficiency = burns lots of fuel. Fighters can chew through thousands of gallons of jet fuel each hour just cruising. Temperature (melting point of metal) is a huge limit to the perf of these engines. Afterburners burn even more fuel in a way that isn't as temperature constrained, but is even less efficient. Modern fighters can burn through their fuel in something like a half hour of combat. RAMjets work by using a constriction at the intake (rather than a fan) to pressurize the air. RAMjets don't work at low speeds, and are better designed to operate at a single design point. They typically run in the low mach numbers, although to operate, the intake air must be slowed to subsonic speeds. They are fast and efficient, but not very flexible. Typically used on missiles (due to their tendancy to operate in a single regime). SCRAMjets are the same basic idea as a RAMjet, but the intake air remains supersonic. Rockets do not burn any atmospheric O2 at all. For this reason, they operate equally well (or poor) at all speeds and air densities, providing a consistent predictable thrust. Due to the need to carry O2 around (which is far heavier than most of the fuels), their efficiency is appalling when compared to air-breathing engines. The uber-efficient space shuttle engines (2H2 + O2 -> 2H2O) have a specific impulse of ~440s. Solid rockets are more like ~200s. Kerosene rockets are in between. Air-breathing engines are in the thousands.