Is it just me, or does the phrase "P2P companies" strike anyone else as an oxymoron? I mean, isn't the whole point of a peer-to-peer protocol that you don't need some centralized service that needs a company to run it?
Fluidics. Fluid (hydraulic or pneumatic) logic circuits. Actually a rather simple form of such is found (or used to be) in automobile automatic transmissions, to control shifting.
They tend to be bulky, require a fair bit of power to keep the fluid circulating, and a bit of a pain to assemble (multiple planes with the paths and logic elements cut out). OTOH, with recent advances in micromachining, we may see such more widely used. A processor that can operate in extreme environments (heat of a jet engine or furnace, high radiation, etc) can come in handy.
That's true for some light twins, especially if they're flying at or near full load. That class of aircraft is sometimes called "doctor killers" because doctors tend to be people with enough money to own one but not enough time to spend much of it practising emergency procedures. (A twin is much harder to control if one engine goes out, especially in the first few seconds after engine failure.)
My father-in-law, who is a doctor, used to own just such (a Cessna 310). Mind, he's also an Air Force officer (retired).
Any time I (I'm also a pilot) or any pilot I know has flown a single over open water it's after calculating the altitude needed to glide to shore if the engine quits at the halfway point. Well', except of course for float planes or other amphibs.
So, yes, churches, summer camps etc. movies are illegal.
Maybe, maybe not. I recall that my kids' summer daycare had paid some nominal, blanket licensing fee that allowed them to show videos to the kids. Possibly excluding Disney films, I never learned all the details (this was last summer), but do recall there were some videos they couldn't show because they weren't covered.
I did one of those once. This was years ago, back when networks were a 2400 baud serial link if you were lucky, and I was transferring an application development environment to a new machine by 'tar'ing onto a removable hard drive (a 2.5 MB RL02, as I recall) on one machine and walking it across campus to the other machine and 'tar'ing it off again.
Ever notice how close together on the keyboard the 'x' and the 'c' keys are? Aaugh!
On the upside, I don't think I've ever hit return on a command with typos as 'root' since.
Well, kind of. Technically, TECO wasn't a programming language but a text editor (and corrector). Emacs wasn't so much a program written in it but a collection of editing macros for it.
I'll agree, though, that it looks like line noise.
I think your lander point is totally false -when did they examine landers that had been there for YEARS?
Apollo 12, 1969. Landed a few hundred yards from Surveyor III, which had landed 3 years earlier. Conrad and Bean walked over to it, clipped off some parts (including a digger arm and the TV camera) and returned them to Earth. It was part of the mission plan.
Bacteria were found within the camera housing.
(As for reentry, while the outer surface of meteorites is charred and melted, the transition through the atmosphere is fast enough that the center stays cool. Rock is a lousy heat conductor.)
(Oh, and the Canadian shield is a fairly small percentage of the exposed rock surface of this planet -- most of which is sedimentary.)
I shall. I'm not saying you're wrong -- it does seem too trivial a thing to have changed from an earlier edition. (Unlike the direction of rotation of the Earth, which Niven messed up in "Ringworld";-)
According to the stats at this link (thanks to an earlier poster), IE share is declining, with IE6 being only 72% and IE5 just over 8%. Mozilla (>12%) makes up most of the rest, with Opera, Netscape and others trailing.
The 95% figure may be the Windows share of the market (more like 94.5% by that link), but not everyone using Windows uses IE. (If I'm setting up a desktop that has to have Windows, Mozilla is the first app I load on it, and then remove the IE icon from the desktop.)
The recent notices from Homeland Security about IE being unsafe will only accelerate this.
See the parts about only using (external) propulsion to install it in the first place, and about the beanstalk mass being much greater (orders of magnitude) than payload mass.
Unless you're catching (or throwing) asteroids, the overwhelming forces on the cable should be "centrifugal" force (I know, not a real force) and Earth's gravity. Anything else should be in the second or third decimal place.
Sorry, but thermodynamically rockets are among the most efficient machines around. They are very good at converting chemical energy to thrust.
The thing is, they have to take their reaction mass with them.
With an elevator, the elevator cables (and counterweight) are the reaction mass. Don't forget to calculate the energy and fuel required to build/deploy the elevator in the first place. Sure, because it stays there (instead of dissipating like rocket exhaust) it will, with enough use, eventually be far more effective than a rocket.
(Oh, and about that shuttle fuel thing -- that first 20% isn't just to lift the rest of it to 500 feet, it's also to accelerate it to whatever speed it's going at that point (100 mph or so upwards). Otherwise they could just build a 500 foot hill (biggest in Florida;-) to put the pad on and save all that fuel...)
Except for the construction phase, the elevator cable already has all the angular momentum it needs. (Granted, it'll need propulsion during the construction phase). The only additional force is whatever is required to increase the angular mo of the payload -- and the payload had darn well better be a tiny fraction of the mass of the cables (and counterweight) or the whole thing comes crashing down as the overall CG suddenly drops below geosynch.
If the anchor point is too weak to transfer that (relatively small) amount of angular momentum (gradually, over the several days to climb the beanstalk), it's too weak to stand up to the force from a strong breeze.
Why not? It makes the dynamics a whole lot easier -- just make sure the CG of the tether is above geosynch. You may have to make the tether a little stronger, but it really simplifies everything else.
Just because the tether is attached to the Earth doesn't mean that it's supported by it. Take a look at the ends of the cables on a suspension bridge -- they're certainly attached to the ground, by they're trying their darndest to pull away. The idea is that the whole beanstalk is under tension, so you tie one end to the ground and have the CG moving at superorbital velocity (ie in a 24 hour orbit above geosynch).
I'd certainly be more comfortable with this arrangement -- it implies a level of overdesign with a margin of error, rather than just having the bottom end of the cable kind of hovering in place.
I know I've called it that (in a Martian context), although Charles Sheffield (in "Web Between The Worlds", 1979) may have been the first to use that term. I do recall a discussion with Niven about "growing" one to orbit ("a real beanstalk"), but there's nothing that has that kind of compressive strength (needed until the CG reaches synchronous orbit).
AFAIR Heinlein only ever used the concept in one story ("Friday"), and called it a skyhook.
Really, the term "elevator" ought to apply to the thing that rides the cable up and down, and calling something vertical a "bridge" just seems...wrong.
There's no way to know who it is that just reeled off nine digits which pass the SSN checksum test.
It's worse than that. There is no "SSN checksum test" -- US SSNs have no checkdigit, with all that implies. (There are some numbers that are clearly "wrong", but checking those requires a look-up, not a simple algorithmic check. That won't catch accidentally (or deliberately) transposed or substituted (eg 8 for 3) digits.)
There are plenty of other reasons why SSN makes a lousy database key (hence a lousy ID number), including the facts that some individuals have multiple SSNs, and that the SSA has occasionally given out the same SSN to different people (who happened to have the same name and birthdate, in some cases).
During WW2, civilians were legitimate military targets.
Not really. The factories churning out military equipment (including the components thereof, like ball-bearings) were the targets, as were transportation hubs (rail yards, docks), they just happened to be in areas surrounded by lots of civilians, and "precision bombing" was an oxymoron. (Unguided gravity bombs dropped from aircraft, with lousy navigation systems, that were being shot at.)
Email doesn't need to be "handled" by anyone - the software can do it all.
Except when the software doesn't, and then someone (usually read as "sys admin") may have to look at it to see what the problem is. Which happens rather more often than, say, the Post Office having to open a letter to figure out the addressee (or sender) because the front of the envelope smeared. (Had to do that today, as a matter of fact -- a bunch of undelivered messages stuck in the mail queue.)
Furthermore, "the software" can -- and frequently does -- also scan all the email looking for items of interest before reporting same to its human master(s). This could be something gov't mandated like Carnivore, or benign like a virus filter, or questionable like a corporate-mandated scan of outgoing email for certain keywords (trade secrets, spam, pr0n, whatever), but it happens. (In the latter case, encrypted email might just be blocked except from certain authorized users.)
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Is it just me, or does the phrase "P2P companies" strike anyone else as an oxymoron? I mean, isn't the whole point of a peer-to-peer protocol that you don't need some centralized service that needs a company to run it?
Actually, the Vietnam War was already well underway when Kennedy took office.
You misspelled "Johnson", or perhaps "Nixon". There weren't more than a few handfuls of "military advisors" in Viet Nam when Kennedy took office.
Perhaps you were talking about the French?
Fluidics. Fluid (hydraulic or pneumatic) logic circuits. Actually a rather simple form of such is found (or used to be) in automobile automatic transmissions, to control shifting.
They tend to be bulky, require a fair bit of power to keep the fluid circulating, and a bit of a pain to assemble (multiple planes with the paths and logic elements cut out). OTOH, with recent advances in micromachining, we may see such more widely used. A processor that can operate in extreme environments (heat of a jet engine or furnace, high radiation, etc) can come in handy.
That's true for some light twins, especially if they're flying at or near full load. That class of aircraft is sometimes called "doctor killers" because doctors tend to be people with enough money to own one but not enough time to spend much of it practising emergency procedures. (A twin is much harder to control if one engine goes out, especially in the first few seconds after engine failure.)
My father-in-law, who is a doctor, used to own just such (a Cessna 310). Mind, he's also an Air Force officer (retired).
Any time I (I'm also a pilot) or any pilot I know has flown a single over open water it's after calculating the altitude needed to glide to shore if the engine quits at the halfway point. Well', except of course for float planes or other amphibs.
So, yes, churches, summer camps etc. movies are illegal.
Maybe, maybe not. I recall that my kids' summer daycare had paid some nominal, blanket licensing fee that allowed them to show videos to the kids. Possibly excluding Disney films, I never learned all the details (this was last summer), but do recall there were some videos they couldn't show because they weren't covered.
Ah yes, destructive typos.
I did one of those once. This was years ago, back when networks were a 2400 baud serial link if you were lucky, and I was transferring an application development environment to a new machine by 'tar'ing onto a removable hard drive (a 2.5 MB RL02, as I recall) on one machine and walking it across campus to the other machine and 'tar'ing it off again.
Ever notice how close together on the keyboard the 'x' and the 'c' keys are? Aaugh!
On the upside, I don't think I've ever hit return on a command with typos as 'root' since.
Well, kind of. Technically, TECO wasn't a programming language but a text editor (and corrector). Emacs wasn't so much a program written in it but a collection of editing macros for it.
I'll agree, though, that it looks like line noise.
Made it a little difficult for anyone else to login since they didn't have access to their ssh keys (or their $HOME, for that matter).
a programmer I met years ago said it was the only language where the source code reminded him of line noise [emphasis added]
He'd obviously never seen APL -- one the few languages terser and more cryptic than Perl, and (AFAIK) the only one to require its own font.
However, they used very sophisticated modelling and milling techniques (I think the term "developed for the space industry" was banded about)
Heh. Developed for manufacturing silent propellors for nuclear submarines, more likely.
Two words: open firmware.
(And yes, this is probably why Mac cards work on a Sun.)
I think your lander point is totally false -when did they examine landers that had been there for YEARS?
Apollo 12, 1969. Landed a few hundred yards from Surveyor III, which had landed 3 years earlier. Conrad and Bean walked over to it, clipped off some parts (including a digger arm and the TV camera) and returned them to Earth. It was part of the mission plan.
Bacteria were found within the camera housing.
(As for reentry, while the outer surface of meteorites is charred and melted, the transition through the atmosphere is fast enough that the center stays cool. Rock is a lousy heat conductor.)
(Oh, and the Canadian shield is a fairly small percentage of the exposed rock surface of this planet -- most of which is sedimentary.)
Well, you should read "Friday" again.
;-)
I shall. I'm not saying you're wrong -- it does seem too trivial a thing to have changed from an earlier edition. (Unlike the direction of rotation of the Earth, which Niven messed up in "Ringworld"
According to the stats at this link (thanks to an earlier poster), IE share is declining, with IE6 being only 72% and IE5 just over 8%. Mozilla (>12%) makes up most of the rest, with Opera, Netscape and others trailing.
The 95% figure may be the Windows share of the market (more like 94.5% by that link), but not everyone using Windows uses IE. (If I'm setting up a desktop that has to have Windows, Mozilla is the first app I load on it, and then remove the IE icon from the desktop.)
The recent notices from Homeland Security about IE being unsafe will only accelerate this.
So, on top of the 500 foot hill you mount a really big spring that will accelerate the rocket to 100 mph. Done!
;-)
How about building a really huge steam catapult (as used to launch aircraft from carriers, only bigger) up the side of the hill?
Re-read previous message.
See the parts about only using (external) propulsion to install it in the first place, and about the beanstalk mass being much greater (orders of magnitude) than payload mass.
Unless you're catching (or throwing) asteroids, the overwhelming forces on the cable should be "centrifugal" force (I know, not a real force) and Earth's gravity. Anything else should be in the second or third decimal place.
Nah, you make it stronger by making it thicker.
That may mean you need to taper it a little bit more (thicker as it approaches CG), but so what?
(Theoretically you could build the thing out of graphite or even kevlar fibers but (for Earth) the taper factor gets ridiculous)
Sorry, but thermodynamically rockets are among the most efficient machines around. They are very good at converting chemical energy to thrust.
;-) to put the pad on and save all that fuel...)
The thing is, they have to take their reaction mass with them.
With an elevator, the elevator cables (and counterweight) are the reaction mass. Don't forget to calculate the energy and fuel required to build/deploy the elevator in the first place. Sure, because it stays there (instead of dissipating like rocket exhaust) it will, with enough use, eventually be far more effective than a rocket.
(Oh, and about that shuttle fuel thing -- that first 20% isn't just to lift the rest of it to 500 feet, it's also to accelerate it to whatever speed it's going at that point (100 mph or so upwards). Otherwise they could just build a 500 foot hill (biggest in Florida
Accelerate what from the ground?
Except for the construction phase, the elevator cable already has all the angular momentum it needs. (Granted, it'll need propulsion during the construction phase). The only additional force is whatever is required to increase the angular mo of the payload -- and the payload had darn well better be a tiny fraction of the mass of the cables (and counterweight) or the whole thing comes crashing down as the overall CG suddenly drops below geosynch.
If the anchor point is too weak to transfer that (relatively small) amount of angular momentum (gradually, over the several days to climb the beanstalk), it's too weak to stand up to the force from a strong breeze.
the tether isn't tightly bound to the Earth.
Why not? It makes the dynamics a whole lot easier -- just make sure the CG of the tether is above geosynch. You may have to make the tether a little stronger, but it really simplifies everything else.
Just because the tether is attached to the Earth doesn't mean that it's supported by it. Take a look at the ends of the cables on a suspension bridge -- they're certainly attached to the ground, by they're trying their darndest to pull away. The idea is that the whole beanstalk is under tension, so you tie one end to the ground and have the CG moving at superorbital velocity (ie in a 24 hour orbit above geosynch).
I'd certainly be more comfortable with this arrangement -- it implies a level of overdesign with a margin of error, rather than just having the bottom end of the cable kind of hovering in place.
Where did Heinlein ever call it a beanstalk?
I know I've called it that (in a Martian context), although Charles Sheffield (in "Web Between The Worlds", 1979) may have been the first to use that term. I do recall a discussion with Niven about "growing" one to orbit ("a real beanstalk"), but there's nothing that has that kind of compressive strength (needed until the CG reaches synchronous orbit).
AFAIR Heinlein only ever used the concept in one story ("Friday"), and called it a skyhook.
Really, the term "elevator" ought to apply to the thing that rides the cable up and down, and calling something vertical a "bridge" just seems...wrong.
There's no way to know who it is that just reeled off nine digits which pass the SSN checksum test.
It's worse than that. There is no "SSN checksum test" -- US SSNs have no checkdigit, with all that implies. (There are some numbers that are clearly "wrong", but checking those requires a look-up, not a simple algorithmic check. That won't catch accidentally (or deliberately) transposed or substituted (eg 8 for 3) digits.)
There are plenty of other reasons why SSN makes a lousy database key (hence a lousy ID number), including the facts that some individuals have multiple SSNs, and that the SSA has occasionally given out the same SSN to different people (who happened to have the same name and birthdate, in some cases).
During WW2, civilians were legitimate military targets.
Not really. The factories churning out military equipment (including the components thereof, like ball-bearings) were the targets, as were transportation hubs (rail yards, docks), they just happened to be in areas surrounded by lots of civilians, and "precision bombing" was an oxymoron. (Unguided gravity bombs dropped from aircraft, with lousy navigation systems, that were being shot at.)
I predict a big comeback in tacky-looking foil wallpaper.
Or aluminum siding.
Email doesn't need to be "handled" by anyone - the software can do it all.
Except when the software doesn't, and then someone (usually read as "sys admin") may have to look at it to see what the problem is. Which happens rather more often than, say, the Post Office having to open a letter to figure out the addressee (or sender) because the front of the envelope smeared. (Had to do that today, as a matter of fact -- a bunch of undelivered messages stuck in the mail queue.)
Furthermore, "the software" can -- and frequently does -- also scan all the email looking for items of interest before reporting same to its human master(s). This could be something gov't mandated like Carnivore, or benign like a virus filter, or questionable like a corporate-mandated scan of outgoing email for certain keywords (trade secrets, spam, pr0n, whatever), but it happens. (In the latter case, encrypted email might just be blocked except from certain authorized users.)