A good password today at a minimum 8 characters, and can consist of any one of 95 keypresses on the keyboard. 95^8 = 6.6e15 combinations. If you don't use special characters, that 8 character password is only 62^8 = 2.2^14 combinations. If you don't use numbers, that 8 character password is only 52^8 = 5.3^13 combinations. And If you don't even bother to change cases, that 8 character password is 26^8 = 2.1e11 combinations.
And if you make your all-lowercase password 12 characters long, you get 26^12 = 9.5e16 combinations, in a form that's a hell of a lot easier to remember than your eight random keypresses.
Increasing length is a much faster way of building security than increasing variety. Password entropy (measured in bits) grows at O(log n) with respect to character variety, and at O(n) with respect to length.
*never quite understood that - it's not *that* much harder than the blocks-and-holes puzzles they solved as a toddler. Well, except the identical but non-interchangable PS-2 mouse and keyboard plugs - those were always a headache if you couldn't see the labels.
The PS/2 mouse, the PS/2 keyboard, and the Zip drive power connector all use a 6-pin mini-DIN plug, and are completely non-interchangeable (plug a mouse into your Zip drive, it doesn't work. Plug a Zip drive power brick into your computer, and watch the sparks fly).
The PC parallel port and the Mac external SCSI port both use female DB-25 connectors; confusingly, parallel-port printers have male Centronics 36-pin ports, so you need a mismatched cable to plug your printer in. Further confusing the issue, Zip drives, scanners, webcams, and just about any other peripheral you can imagine plugs into the parallel port, usually with daisy-chaining that never quite worked properly.
The modem jack and phone passthrough jack are identical, but few modems will work properly if attached backwards. Further, you can plug a phone cord into an RJ-45 Ethernet port, but it won't work.
Mice come in both DB-9 serial and PS/2 mini-DIN format, and speak different protocols, so if you've got an adapter, you also need to make sure the protocol selector switch on the mouse is set correctly. Similarly, keyboards come in both PS/2 mini-DIN and 5-pin DIN format, and speak both the AT and XT protocols.
Serial ports come in four flavors: DB-25 male RS-232, DB-9 male RS-232, DB-9 male RS-422, and 8-pin mini-DIN RS-422 (the latter two seen mainly on Macintosh computers). You can sometimes use passive adapters to switch between them, but there's always the possibility of having an RS-422 device that's picky about the signaling details, or an RS-232 device that needs the extra control lines of the 25-pin connector.
Analog video is usually either female DE-15 or DE-9, but computers made by Apple use female DB-15 -- and the Apple and Macintosh lines use different signaling protocols over the same DB-15 connector, neither of which is compatible with the PC's DE-15 standard.
Older joysticks usually have unshielded female DE-9 plugs (and so can attach to DB-9 serial ports, but tend to let the magic smoke out if so used). Newer joysticks use shielded DA-15 connectors, and if the joystick port is on a sound card, it doubles as a MIDI port. You can attach a Y-cable to your joystick port to plug in two joysticks (assuming both are basic two-axis two-button models), but you can't daisy-chain Y-cables to plug in more, and you can't use it as a splitter to plug both a MIDI device and a joystick in.
Also on the subject of sound cards, your computer probably has three 3.5mm three-connector jacks: two on the back, and one on the CD-ROM drive. One of the jacks on the back is for speakers while the other is for a microphone; the one on the drive lets you use the drive as a CD player by plugging in headphones, and won't play sounds produced by the sound card.
The shielded coaxial connector on the back of your computer? It might be Ethernet, it might be Token Bus, or it might be composite video. Have fun!
Didn't Columbus claim the Americas in the name of Spain when he planted a flag?
Yes. From his letter describing his voyage, "...where I found very many islands peopled with inhabitants beyond number. And of them all I have taken possession for their Highnesses with proclamation and the royal standard displayed and I was not gainsaid..."
Did we not do the same when we planted a flag on the moon?
Armstrong didn't make any such proclamation when he planted the US flag on the Moon, and I don't believe any of the later mission commanders did, either.
2.7 sigma isn't actually that much: assuming a Gaussian distribution of data, it's a one-in-a-hundred chance of being randomness rather than a real difference (or in other terms, about one experiment in a hundred will generate a false signal). For comparison, the standard for announcing a new particle is 5 sigma (1 in 1.7 million chance of it being a false positive).
Also, a general question on efficiencies; Do the higher power rated PSUs generally have higher efficiencies at lower power outputs? IOW, given 2 comparable model 'high efficiency' PSU's, one rated at 1000W and the other at 500W, would the 1000W one be more efficient than the 500W one at, say, 250W?
PSUs usually hit their peak efficiency somewhere between 50% and 75% load, with the efficiency curve being reasonably flat between 25% and 90% load. Efficiency drops off fast at low loads, with the efficiency at 5% load typically being half to two-thirds that at full load.
Or don't: it comes out at several tens of years in any realistic scenario.
Scenario 1: an always-on computer running near-idle for four years.
Idle power draw, 85% efficient PSU: 66 watts Idle power draw, 80% efficient PSU: 70 watts Delta: 4 watts Total power difference over the four-year life of the computer: 140 kilowatt-hours. At 5.5 cents per kilowatt-hour (cheapest power in the US), building with a more-efficient power supply makes sense if it costs no more than $7.70 beyond what the less-efficient power supply does.
Scenario 2: an always-on computer running Folding@Home for four years using both CPU and GPU.
Power draw, 90% efficient PSU: 215 watts Power draw, 80% efficient PSU: 245 watts Delta: 30 watts Total power difference over the four-year life of the computer: 1.05 megawatt-hours. At 36 cents per kilowatt-hour (most expensive power in the US), building with a more-efficient power supply makes sense if it costs no more than $378 beyond what a less-efficient power supply does.
The second scenario represents someone running F@H on a modern high-end computer in Hawaii -- not exactly "unrealistic".
That list is technically correct, but not useful. It's basically a list of every hydrogen airship where fire played a part in its destruction. For example, it includes LZ-30 (crashed, then the escaping hydrogen caught fire -- it was "destroyed by hydrogen" in the same way that an airplane that crashed and burned was "destroyed by jet fuel"), ZR-2 (broke up mid-flight, the engines caught fire and ignited the hydrogen), and LZ-87, LZ-94, LZ-97, and LZ-105, destroyed in a mysterious hangar explosion (sabotage was suspected but not proven).
Of the airships listed, only LZ-18, LZ-40, SL-6, the Wingfoot Air Express, and the Hindenburg were definitely lost due to in-flight hydrogen fires, while the SL-9, LZ-104, and Dixmude may have been. The other nineteen entries in that list either burned after crashing, or caught fire on the ground (usually during maintenance).
Why? Doesn't the system need some sort of root fs to boot? I am asking out of ignorance and curiosity, nothing else.
No, it doesn't. At boot time (specifically, at the point where execution transfers out of the boot ROM (eg. BIOS)), there just needs to be a blob of executable code at a known location in RAM.
For example, I've got a diskless system that netboots: the kernel image gets passed from the netboot server to the client RAM over a TFTP connection; the root filesystem (served over NFS) doesn't show up until a goodly chunk of the kernel has been initialized. As should be obvious, this means I can't use a network card that requires external firmware.
The avatar idea here is pretty cool, but not even the author seems to understand why they don't just cut to eye-tracking, instead of the whole: reading the patients mind to determine what they are looking at. It looks to me to be an easy way to over complicate an already difficult project.
Eye tracking doesn't actually work that well for anything other than large-scale movements. You may think you're staring intently at that can of beer, but actually your center of focus is jumping all over the place. With luck, brain tracking will work better.
However the idea that you can patent rounded corners...
Rounded corners are (or at least, should be) a design patent, which protects the purely ornamental elements of a product's design. If those elements turn out to have practical utility, the design patent is invalidated. The classic example of a design patent is the one on the shape of the Coca-Cola bottle.
...a natural characteristic of a vigorously competitive industry. And they're nothing new: Similar skirmishes have historically occurred in areas as diverse as...winged flight,
In my state, "sex offenders" include people who have urinated in public, people who forgot to close the bathroom shades before getting out of the shower, and a great many teenagers who couldn't keep it in their pants. Are these the "depraved and psychotic people" whose lives you wish to destroy?
Did anyone here a call of engine cut-off in the NASA TV feed? I did not. Or a call for a longer burn? Seems the SpaceX team would have made those calls.
The decision to shut down engine #1 and the decision to adjust the other engines' burns to compensate were made automatically by the flight-control computer onboard the rocket. There's no need for the ground team to make the decisions, and no need for the computer to make voice announcements about them.
(Obligatory car analogy: it would be like having your car's ECU call your mechanic to announce that it's adjusted the spark timing to compensate for driver error.)
With WiFi speeds getting so high, range being respectable, and just about everyone wanting wireless data (see: cell phones, tablets, and laptops) why aren't ISPs making extensive use of WiFi for the last mile?
WiFi is a "last-inch" technology, not a "last-mile" technology. The high speeds you can get from consumer gear assume that there's little to no contention for the radio spectrum involved; if you're feeding an entire city block off a single access point, you've got several dozen people contending for that same chunk of bandwidth. If all of them decide to watch YouTube or whatever at the same time, that theoretical 600-megabit data rate drops down to maybe 5 half-duplex megabits per customer, as the weaknesses of a shared-medium network kick in.
You can work around the contention problem by increasing the number of base stations. If you've got one access point per house, each device talks to the nearest base station and has a stronger signal that keeps more distant devices from interfering, but you're back where you started, needing to run a wire to each house.
We do work with Titanium sometimes, which requires us to maintain Class D extinguishers.
Make sure you coordinate with the local fire department on this. One company I worked for didn't, and there was a bit of excitement when a tray containing 50 pounds of magnesium shavings caught fire. The company's stock of class D extinguishers wasn't enough to put it out, and when the fire department showed up, it turned out that they didn't have anything to fight exotic-metal fires with.
However in the specific scenario described, no jury would convict, and it would be very unlikely to go to court: A harrowing account from the victim's perspective, on a forum for fellow victims.
Someone copies it to an erotic-literature site. The thought police are monitoring it because it's an easy source of convictions. The posting is done anonymously, but the account contains enough information to identify the author. Guess who gets arrested?
You're thinking of patents and prior art. Trademarks don't work that way - they belong to whoever registers them in specific categories.
Within limits. If a term is already in common use, it's quite difficult to get a trademark for it. You cannot, for example, get a trademark on "Windows" for your brand of wall openings.
A six-inch version 40 code has pixels slightly less than a millimeter on a side. If you carve the code deep enough to survive a century of erosion, isolated raised pixels are likely to break off either during the carving process or with the first freeze/thaw cycle.
To survive a century, you really want the minimum feature size to be at least five millimeters, which works out to a version 40 code that's three feet across.
My dad had symptoms of a stroke - which are similar. First thing he got? A dose of blood thinners and a brain scan at a local hospital.
In that order? Sounds like a malpractice suit waiting to happen. Give blood thinners to someone with an ischemic stroke, you get a miracle cure. Give blood thinners to someone with a hemorrhagic stroke, you kill them. That's why you try to figure out what's going on before you start treatment.
Don't think because you pay a lot of money that your RV is reliable
My parents found that the most accurate "quick and dirty" check for quality was to look at the cabinet doors: a quality RV would have metal hinges, wooden handles, and solid-wood doors. An inferior RV would have plastic hinges, plastic handles, particle-board doors, and gold trim all over the place to distract you from the above. In general, within a price range, build quality is inversely proportional to the number of gratuitous reflective surfaces.
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And if you make your all-lowercase password 12 characters long, you get 26^12 = 9.5e16 combinations, in a form that's a hell of a lot easier to remember than your eight random keypresses.
Increasing length is a much faster way of building security than increasing variety. Password entropy (measured in bits) grows at O(log n) with respect to character variety, and at O(n) with respect to length.
"Rare earths" aren't really all that rare. What's rare is finding them in high concentrations.
The big problem is that birds will eat the pellets as gizzard stones, and there is absolutely no doubt that this cause lead poisoning.
The PS/2 mouse, the PS/2 keyboard, and the Zip drive power connector all use a 6-pin mini-DIN plug, and are completely non-interchangeable (plug a mouse into your Zip drive, it doesn't work. Plug a Zip drive power brick into your computer, and watch the sparks fly).
The PC parallel port and the Mac external SCSI port both use female DB-25 connectors; confusingly, parallel-port printers have male Centronics 36-pin ports, so you need a mismatched cable to plug your printer in. Further confusing the issue, Zip drives, scanners, webcams, and just about any other peripheral you can imagine plugs into the parallel port, usually with daisy-chaining that never quite worked properly.
The modem jack and phone passthrough jack are identical, but few modems will work properly if attached backwards. Further, you can plug a phone cord into an RJ-45 Ethernet port, but it won't work.
Mice come in both DB-9 serial and PS/2 mini-DIN format, and speak different protocols, so if you've got an adapter, you also need to make sure the protocol selector switch on the mouse is set correctly. Similarly, keyboards come in both PS/2 mini-DIN and 5-pin DIN format, and speak both the AT and XT protocols.
Serial ports come in four flavors: DB-25 male RS-232, DB-9 male RS-232, DB-9 male RS-422, and 8-pin mini-DIN RS-422 (the latter two seen mainly on Macintosh computers). You can sometimes use passive adapters to switch between them, but there's always the possibility of having an RS-422 device that's picky about the signaling details, or an RS-232 device that needs the extra control lines of the 25-pin connector.
Analog video is usually either female DE-15 or DE-9, but computers made by Apple use female DB-15 -- and the Apple and Macintosh lines use different signaling protocols over the same DB-15 connector, neither of which is compatible with the PC's DE-15 standard.
Older joysticks usually have unshielded female DE-9 plugs (and so can attach to DB-9 serial ports, but tend to let the magic smoke out if so used). Newer joysticks use shielded DA-15 connectors, and if the joystick port is on a sound card, it doubles as a MIDI port. You can attach a Y-cable to your joystick port to plug in two joysticks (assuming both are basic two-axis two-button models), but you can't daisy-chain Y-cables to plug in more, and you can't use it as a splitter to plug both a MIDI device and a joystick in.
Also on the subject of sound cards, your computer probably has three 3.5mm three-connector jacks: two on the back, and one on the CD-ROM drive. One of the jacks on the back is for speakers while the other is for a microphone; the one on the drive lets you use the drive as a CD player by plugging in headphones, and won't play sounds produced by the sound card.
The shielded coaxial connector on the back of your computer? It might be Ethernet, it might be Token Bus, or it might be composite video. Have fun!
The main unclassified use for the Shuttle's cargo return ability was Spacelab missions.
Yes. From his letter describing his voyage, "...where I found very many islands peopled with inhabitants beyond number. And of them all I have taken possession for their Highnesses with proclamation and the royal standard displayed and I was not gainsaid..."
Armstrong didn't make any such proclamation when he planted the US flag on the Moon, and I don't believe any of the later mission commanders did, either.
2.7 sigma isn't actually that much: assuming a Gaussian distribution of data, it's a one-in-a-hundred chance of being randomness rather than a real difference (or in other terms, about one experiment in a hundred will generate a false signal). For comparison, the standard for announcing a new particle is 5 sigma (1 in 1.7 million chance of it being a false positive).
PSUs usually hit their peak efficiency somewhere between 50% and 75% load, with the efficiency curve being reasonably flat between 25% and 90% load. Efficiency drops off fast at low loads, with the efficiency at 5% load typically being half to two-thirds that at full load.
Scenario 1: an always-on computer running near-idle for four years.
Idle power draw, 85% efficient PSU: 66 watts
Idle power draw, 80% efficient PSU: 70 watts
Delta: 4 watts
Total power difference over the four-year life of the computer: 140 kilowatt-hours.
At 5.5 cents per kilowatt-hour (cheapest power in the US), building with a more-efficient power supply makes sense if it costs no more than $7.70 beyond what the less-efficient power supply does.
Scenario 2: an always-on computer running Folding@Home for four years using both CPU and GPU.
Power draw, 90% efficient PSU: 215 watts
Power draw, 80% efficient PSU: 245 watts
Delta: 30 watts
Total power difference over the four-year life of the computer: 1.05 megawatt-hours.
At 36 cents per kilowatt-hour (most expensive power in the US), building with a more-efficient power supply makes sense if it costs no more than $378 beyond what a less-efficient power supply does.
The second scenario represents someone running F@H on a modern high-end computer in Hawaii -- not exactly "unrealistic".
That list is technically correct, but not useful. It's basically a list of every hydrogen airship where fire played a part in its destruction. For example, it includes LZ-30 (crashed, then the escaping hydrogen caught fire -- it was "destroyed by hydrogen" in the same way that an airplane that crashed and burned was "destroyed by jet fuel"), ZR-2 (broke up mid-flight, the engines caught fire and ignited the hydrogen), and LZ-87, LZ-94, LZ-97, and LZ-105, destroyed in a mysterious hangar explosion (sabotage was suspected but not proven).
Of the airships listed, only LZ-18, LZ-40, SL-6, the Wingfoot Air Express, and the Hindenburg were definitely lost due to in-flight hydrogen fires, while the SL-9, LZ-104, and Dixmude may have been. The other nineteen entries in that list either burned after crashing, or caught fire on the ground (usually during maintenance).
No, it doesn't. At boot time (specifically, at the point where execution transfers out of the boot ROM (eg. BIOS)), there just needs to be a blob of executable code at a known location in RAM.
For example, I've got a diskless system that netboots: the kernel image gets passed from the netboot server to the client RAM over a TFTP connection; the root filesystem (served over NFS) doesn't show up until a goodly chunk of the kernel has been initialized. As should be obvious, this means I can't use a network card that requires external firmware.
Eye tracking doesn't actually work that well for anything other than large-scale movements. You may think you're staring intently at that can of beer, but actually your center of focus is jumping all over the place. With luck, brain tracking will work better.
Rounded corners are (or at least, should be) a design patent, which protects the purely ornamental elements of a product's design. If those elements turn out to have practical utility, the design patent is invalidated. The classic example of a design patent is the one on the shape of the Coca-Cola bottle.
You mean the skirmishes that left Europe doing all the innovating in winged flight for 20 years? The ones that resulted in the US entering World War I with airplanes that weren't much better than the Flyer III?
In my state, "sex offenders" include people who have urinated in public, people who forgot to close the bathroom shades before getting out of the shower, and a great many teenagers who couldn't keep it in their pants. Are these the "depraved and psychotic people" whose lives you wish to destroy?
Phase 1 trials are the "prove the vaccine doesn't give you AIDS" (or cause other medical problems) stage of things.
The decision to shut down engine #1 and the decision to adjust the other engines' burns to compensate were made automatically by the flight-control computer onboard the rocket. There's no need for the ground team to make the decisions, and no need for the computer to make voice announcements about them.
(Obligatory car analogy: it would be like having your car's ECU call your mechanic to announce that it's adjusted the spark timing to compensate for driver error.)
WiFi is a "last-inch" technology, not a "last-mile" technology. The high speeds you can get from consumer gear assume that there's little to no contention for the radio spectrum involved; if you're feeding an entire city block off a single access point, you've got several dozen people contending for that same chunk of bandwidth. If all of them decide to watch YouTube or whatever at the same time, that theoretical 600-megabit data rate drops down to maybe 5 half-duplex megabits per customer, as the weaknesses of a shared-medium network kick in.
You can work around the contention problem by increasing the number of base stations. If you've got one access point per house, each device talks to the nearest base station and has a stronger signal that keeps more distant devices from interfering, but you're back where you started, needing to run a wire to each house.
Make sure you coordinate with the local fire department on this. One company I worked for didn't, and there was a bit of excitement when a tray containing 50 pounds of magnesium shavings caught fire. The company's stock of class D extinguishers wasn't enough to put it out, and when the fire department showed up, it turned out that they didn't have anything to fight exotic-metal fires with.
There's just something about the phrase "decision-making ability in brain-damaged monkeys on cocaine"....
Someone copies it to an erotic-literature site. The thought police are monitoring it because it's an easy source of convictions. The posting is done anonymously, but the account contains enough information to identify the author. Guess who gets arrested?
Within limits. If a term is already in common use, it's quite difficult to get a trademark for it. You cannot, for example, get a trademark on "Windows" for your brand of wall openings.
A six-inch version 40 code has pixels slightly less than a millimeter on a side. If you carve the code deep enough to survive a century of erosion, isolated raised pixels are likely to break off either during the carving process or with the first freeze/thaw cycle.
To survive a century, you really want the minimum feature size to be at least five millimeters, which works out to a version 40 code that's three feet across.
In that order? Sounds like a malpractice suit waiting to happen. Give blood thinners to someone with an ischemic stroke, you get a miracle cure. Give blood thinners to someone with a hemorrhagic stroke, you kill them. That's why you try to figure out what's going on before you start treatment.
My parents found that the most accurate "quick and dirty" check for quality was to look at the cabinet doors: a quality RV would have metal hinges, wooden handles, and solid-wood doors. An inferior RV would have plastic hinges, plastic handles, particle-board doors, and gold trim all over the place to distract you from the above. In general, within a price range, build quality is inversely proportional to the number of gratuitous reflective surfaces.