Eh, go run an `openssl speed rsa' benchmark and see what kinds of results you get.
In my MacBook with a Core 2 Duo 2.4 GHz CPU, I get 30 RSA-2048 private-key operations per second, and 1042 public-key operations per second. One of these operations is used on every SSL handshake, not sure which of the two, so I can't really say whether performance is only `really bad' or `eye-poppingly awful'. Sure the performance drain would be a myth if we only used symmetric encryption, but key exchanges can only take place on an insecure channel if public-key encryption is used.
Performance on the client is irrelevant, it doesn't have to perform hundreds if not thousands of encryptions per second like the server does.
Since we're talking about phone bugs, here's one I had to fight with for a while...
Lots of users are having problems with the GPS functionality on the iPhone 3G/3GS (see e.g. here). No apparent pattern there, but in Brazil, lots of users from one specific carrier were having GPS problems, and the beginning of these problems coincided with the start of Daylight Savings Time in Brazil. My iPhone, as well as my girlfriend's, are with this carrier and were experiencing the problem. Those with unlocked phones report trying other carriers' SIM cards and had GPS working again, but once you popped back the problematic carrier's SIM card, the GPS was dead again.
This nearly drove me nuts as I paid an obscene amount of money for the TomTom app and couldn't get it to work, so keeping up with the engineer spirit, I tried to debug the problem myself. I observed an interesting fact: there's a Clock app on the iPhone with a World Clock pane, and if I added a clock from any time zone, including my own, it was off by one hour. However the iPhone's main clock, shown on the top of the screen, was showing the right time. Eventually I discovered that if I restored my phone as a brand new phone (not restoring from backup) the GPS would work fine and world clocks would be fine... until you reboot the phone. After rebooting, the GPS is gone again and the world clock is off by one hour again.
Now you might ask what the time has to do with GPS. A lot, it turns out. GPS works by triangulating your distance from the satellites in the GPS constellation, which depends on knowing the exact position of the satellites. Since their orbits are corrected every so often, you must rely on so-called ephemeris data from each satellite, which is the required information to compute fairly exact orbits, and is updated fairly often (Wikipedia says GPS receivers should update ephemeris data every 4 hours). Originally this data is broadcast by the satellites themselves in their navigation message, at an awfully slow rate of 50 bits/s. You read it right, bits, not bytes or KB or MB, that's bits. As the navigation message is 1500 bits long, it takes at least 30 seconds to download it, which is about the time most standalone GPS receivers take to get a fix from a cold start (i.e. with stale ephemeris data). To work around this delay, most phones with GPS use the assisted-GPS variety, which downloads ephemeris data from a faster channel such as the cellular network. My theory is that some WTF-worthy excuse for an engineer at the carrier decided that, rather than doing time zone updates the right way, by updating configuration files to point to the new time zone, he'd just rather adjust the clock forward by one hour. The GPS chipset probably works with time zone neutral clocks so it asks for (say) UTC time and gets it off by one hour, and then computes the satellite orbits as though it were one hour later than it actually is. Obviously this means the triangulation computations go horribly wrong and rather than reporting something absurd, the chipset just pretends it couldn't get a fix.
It took a lot of complaining from a lot of people (to the carrier and to the government agencies responsible for telecommunications), but the carrier finally fixed the problem. However, it was a nightmare trying to deal with clueless customer support representatives who didn't try in the least to help (and probably were thinking all along `what does this wacko think GPS has to do with DST?'), just blindly suggesting that we restore the phone, or even try to uninstall the built-in Maps app, or blaming it on Apple and saying they weren't responsible -- and never mind that unlocked phones with SIM cards from other carriers worked fine, and that the iPhone support situation is unique in Brazil as Apple outsourced support to the carriers themselves. In the end, the customer support WTFs would be worth another post of its own, at least twice the size of this one.
Is it in fact the case that the Wiimote only senses things correctly in a normal gravitational field?
For orientation (knowing where the Wii-mote is pointing), you pretty much need a gravitational field, since that's a fixed reference: it always points down. In a microgravity environment (or freefall), the Wii just wouldn't know where it was pointing since there's no reference to compare to. Of course, if you need attitude control in a microgravity environment, say a satellite or space station, then you can use other types of sensors, such as gyroscopes (which measure angular acceleration `on their own' and are insensitive to linear acceleration, including gravity).
Another interesting type of sensor, at least if you're on the surface of the earth, are magnetometers. They're a bit harder to calibrate, since the orientation of the earth's magnetic field is not constant across the surface of the earth, but once calibrated, they provide another fixed reference in addition to accelerometers. Assuming rotations only, and since magnetic and gravity fields are generally not aligned, you can solve the `blind axis' problem; even if you have a rotation in an axis aligned either to the magnetic or gravity fields, it won't be aligned to the other field, so you'll be able to sense it. The problem with translations isn't solved yet though; I'll try to illustrate. Let's pretend the magnetic and gravity fields are perpendicular to each other; still, if you consider the orientation of, say, the magnetic field, there's still a whole plane of vectors perpendicular to it, and any one of those could be a valid acceleration vector. So you have your shiny magnetometer-enabled Wii-mote, and apply a rotation to it in the same plane as the gravity vector should be; the addition of these two vectors is a third vector in the same plane, and could easily be mistaken for the gravity vector itself. There's just no way to decompose these back into the gravity and external force components.
That does explain why games that try to use "move the Wiimote forwards, backwards, and side to side" as an X/Y plane tend to be hard to play
Tell me about it. I was trying to use readouts from my MacBook Pro's accelerometers to implement a positioning demo, but what I saw on the screen was just completely uncorrelated to the actual movements. I tried to apply some simplistic filtering schemes but as expected they weren't successful. Oh well, I never did actual inertial engineering work, I only did interfacing and instrumentation work for an inertial engineering project, so I only know the basics of the subject, certainly not the advanced algorithms required to obtain useful data from inertial sensors. I'm actually very impressed from what I read about the Wii -- they seem to have done a very good job, certainly much better than what we achieved in our lab.
Out of curiosity, if they were using more than one 3-axis accelerometer like this one would they still have difficulty with determining pure rotation from other movements?
I believe you mean having a second accelerometer aligned to a different axis. Unfortunately, that doesn't add any extra information; you're still measuring the same physical quantity. Think of this as reading a vector in a canonical coordinate system (say x = (1,0,0), y = (0,1,0), z = (0,0,1)), and then reading the same vector but in a rotated coordinate system; these two are equivalent if you were to apply a certain change of base matrix (a rotation matrix, to be specific), so the second readout will not give you any new information.
Come to think of it, if you were to position the accelerometers in two distinct points of the Wii-mote, then I _think_ (but don't quote me on that) that rotations about non-symmetric axes (i.e. an axis not equidistant to both accelerometers) would give different readouts on each of them. I assume someone much smarter than I am could deduce information about the rotation axis and angle from this information, but I certainly can't think of how. When I said I did some inertial engineering work, this was an undergraduate project and I was just responsible for some interface and instrumentation systems, not the core inertial engineering stuff. What I learned about inertial engineering proper was about summed up on the grandparent post.
Having done some inertial engineering work, I can shed some light on this issue.
The Wii-mote has accelerometers on it. These sense forces applied to it (gravity included), and their combined output is a vector indicating the direction and modulo of the resultant acceleration. Assuming you're standing still, you'd only be subject to the force of gravity, and by definition it always points to the ground. So do a few vector computations and you know the orientation of the Wii-mote. There is a problem with a `blind axis' (rotation in the same axis as gravity can't be detected), but ignore that for now.
On the other hand, if you want to estimate position, here's what you have to do: given an initial position, read the accelerometers, subtract the effect of gravity from the acceleration vector (harder than it seems, since the Wii-mote could be pointing anywhere, really), which then gives the `real acceleration' of the system. Now integrate this once to obtain velocity, and again to obtain position. There's just so much room for error here, that I don't know where to start. Limited accelerometer resolution, poor A/D converters, temperature drift, numerical accuracy issues, you name it. Integrating measurements (not only that, but integrating twice!) is just a recipe for disaster. Then there's a fundamental limitation to accelerometer devices: rotations can't really be distinguished from translations. Just think about it -- a given resultant acceleration vector could be the result of pointing the Wii-mote in any given orientation, added to a specific acceleration in a specific direction. You just don't have enough information to distinguish between the two -- not with accelerometers alone, at least.
A post this badly written doesn't really deserve a response, but here goes:
CDMA (I don't know about GSM) has dynamic power control built in, so that transmission power is kept at the bare minimum required -- why use more power if it isn't really required?
Extra power drains batteries faster.
May interfere with neighboring cells.
In a spread spectrum system (both 3G standards use spread spectrum, so this will apply to most networks in the near future), every transmission occurs on the same frequency band, so someone raising their power level is seen as noise on the other communications, which in turn requires everyone to raise their power level.
Oh, and the turbo button actually slowed down the processor down to the speed of a 4.7 MHz 8086. When in turbo mode the computer would run at nominal speed.
This is just the perfect story for me to plug my latest research, a couple of crypto protocols to help ensure P2P users behave honestly when uploading and storage rewards of some kind are involved, and there exists the incentive to cheat. Hope someone puts them to good use.
Fact is, I've become so used to incoherent, pointless, misspelled, gramatically incorrect, factually incorrect, stream-of-conscionouss postings in Slashdot, that it just never occurred to me this one might be any different.
The project isn't aimed at starving kids in Africa.
Really? Please prove it. I couldn't find definitive prove for or against it, but here's from the FAQ in the official site: Initial discussions have been held with China, India, Brazil, Argentina, Egypt, Nigeria, and Thailand. (emphasis mine on two African nations, although what I meant by Africa in my post was miserable places in general, but I was expecting pedantry just the same).
DSL means Damn Small Linux.
Outside of you 31337 sphere of influence, 99.9% of people will think of DSL as Digital Subscriber Line, if anything. I'll gladly assume that I take pride in being`ignorant' on this case, as opposed to a mindless Linux fanboy who hijacks popular acronyms for their obscure stuff and expects everyone to follow.
Yeah, I'm pretty sure the miserable kids nearly dying of hunger in Africa (remember, that's the kind of people this project is targeting) have the money laying around to pay for DSL, assuming it's even available in their region.
the lack of an annoying built-in DRM selling store (yes, that's actually an *advantage* over iTunes)
War is peace, freedom is slavery, ignorance is strength, right?
I don't live in the US so one of the first things I did was disable iTMS. I completely forgot about iTMS as far as iTunes is concerned.
If Firefox takes half a minute to load, there's a problem elsewhere.
Maybe it's the fact that my Mac is a bit underpowered (G4 1.42 GHz, 4200 RPM HD). Nah, can't be, Linux and open source is the best choice for old machines, as I hear practically every day from slashbots. I cringe at the thought of running OpenOffice at anything with less than 2 GHz of clock and 1 GB RAM. (Off-topic, I know, but couldn't resist.)
The fact remains that Safari is very efficient. In fact, whenever I use a Windows machine, I'm moving away from the habit of installing Firefox and just running IE (even if Firefox is installed), since it's so goddamned slow.
Ever tried VLC? Please tell me why it is garbage.
Why yes, I did. Let's start... the File->Open File... dialog is about as scary as the advanced options of a BIOS screen would be to a newbie. Open the preferences screen, there's hundreds if not thousands of options. I recall having problems playing movies with certain WMV codecs, which of course Flip4Mac runs just fine.
Overall, when I was switching, I had a choice between standard Quicktime (no Pro then) and VLC/MPlayer. Coming from Linux I was actually used to the latter. I couldn't help the fact that I was drawn to Quicktime and currently I only have VLC here as a relic. Quicktime is good enough to me and has that Apple quality which no open source app can achieve, let alone surpass.
News to me (and I used Amarok before switching to the Mac). The most remarking memory I have of it was how often it crashed -- I don't recall iTunes ever crashing on me. Anyway, why do you claim that? Because it plays some obscure format no one cares about?
I have yet to understand what's so great about Safari, compared to Firefox or Konq.
I could start on how it doesn't take half a minute to load, and 15 seconds to be swapped back from the HD whenever I've been away from it for a while, like Firefox does. Then there's the `Apple polish' which is never present on any open source app, even when they try to imitate Apple (since they always mess some details).
Quicktime is crippled garbage. Apple should be ashamed to include a shareware-like app with their OS, especially after the consumer has spent a few grands on their overexpensive hardware.
Quicktime standard is fairly crippled, but I have no complaints about Quicktime Pro. It is certainly much better than the garbage media players available for Linux. Also, I can encode small and good quality video without wading through hundreds of KBs of man pages for weird commandline compression options (*cough*mencoder*cough*).
Jeeze, by my math you pay about half your annual income for a computer. You're retarded.
Considering I didn't specify which Mac I have (a mini which I paid US$ 700 for about a year ago), nor how often I upgrade it (I'm saving to buy a Macbook Pro on 2H 2006, for a 1.5-year upgrade cycle, I'll just have to say that you don't know what the fuck you're talking about. I could pay my bills and save the rest for like 4 months and be able to afford the Macbook Pro in question.
for me gnome is definitely more user friendly (...) have the menu bar where I expect it
Sure, anything you're not used to will be unfriendly at first sight. Give it a week before you issue an opinion. That was about the time it took me to get used to the new menu bar placement when I switched to OS X. Now, being experienced with both menu bar styles, I can state that I find OS X's approach superior.
Indeed. Just compare Eclipse with XCode, OpenOffice with the toy application(s) that apple offers.
I can't even try out Eclipse, I only have a meager 512 MB of RAM which can't accomodate wasteful Java applications (running Azureus is enough of a chore). Xcode is good enough for my needs. Also, some believe iWork to be superior to the bloat of OpenOffice, and those that don't can always run it on OS X. And then there's the non-cheap types, which instead of using MS Office clones like OpenOffice, would rather run MS Office directly. Both of these options (iWork and MS Office) are available on OS X but not Linux.
But these weren't the applications that I was thinking of. How about Safari vs. Konqueror (or even the bloat of Firefox? I keep Firefox here for the couple of sites which don't work correctly with Safari, but I'd really hate to use it as my main browser), how about iTunes vs. XMMS or Amarok or whatever, Quicktime vs. MPlayer/Xine, and then there's the iLife suite (Garageband, iPhoto, iDVD,...) mostly without competitors in the Linux space. I've used KMail and Mail.app and I prefer Mail.app. Also, can you run Photoshop on Linux? I know that was a discussion about bundled applications, but it deserves mention. And no, hacks like Wine don't count.
Until OSX ships with a package manager that handles package dependencies, it is impossible to produce and ship system components for this OS
Because I was not born with a silver spoon in my mouth.
Neither have I. I live in an `emerging' country and barely make US$ 1k/month (and Apple hardware is more expensive, not cheaper, where I live). Yet I am aware of how much extra productivity a Mac affords me, so I save money to buy Apple hardware since it pays itself off in the long run.
I do not have $hitload of money to spend on a shiny uber-cool super-cute hardware.
If you live in a developed country, you probably do, much more than I. Unless you're one of those people who max out their credit cards and can't afford to pay the bill and keep paying interest for the rest of life (I guess if I was that way I wouldn't have bought my Apple, but luckily I'm financially responsible). Maybe buying an Apple is not your priority; if you don't work with computers, that's justifiable. In my case I couldn't afford the lack of productivity due to staying with Linux or even Windows, so I was practically forced to switch.
But I am willing to pay for a 99$ OS X to run on my cheap PC, because I can afford 99$ (against somewhere around 500-3000$).
I guess your original computer cost $0 since you're not taking its cost into account. Anyway, the next time you upgrade, consider getting a Mac, which comes with OS X for free, won't cost much more and will have much higher quality than your current PoS Dell or self-built computer. Otherwise keep drooling over OS X, because Apple sure as hell won't let you run it in anything else but its own hardware.
Having the better product doesn't seem to have helped Apple's market penetration so far, and imitation (*cough* rip off! *cough*) hasn't hurt their main competitor any.
I always thought open source developers took pride in the quality and `innovation' (God, I hate that word) of their software, not market economics. Guess that explains a lot of things.
Thats not true - I seriously would pony up for a version of OSX that would run on any whitebox.
So why don't you pony up for a real Apple computer to get the real Apple experience? Don't tell me you have some Windows apps you need to run, Boot Camp already took care of that excuse.
Apple sells 50 million copies of OS/X between Thanksgiving and New Years to people with MAC envy that normally wouldn't spring for a MAC anyway. ($7.5B instant profit)
With upgrade envy, Apple entices 30% of these OS/X newbys to "upgrade" to a MAC. (~$7.5B instant profit + residual sales for add-on/upgrades).
As a result, Apple will have drastically expanded their customer base, installed OS base, and mindshare within a 6 month window. They would have effectively broken the Microsoft OS monopoly while increasing their hardware business (and raising their stock dramatically.)
Wow, you sure have an impressive crystal ball! Not only have you predicted the scenario but also exact sales figures!
Wait, you didn't happen to pull these figures out of your ass, did you? You seem like a pretty good candidate for John Dvorak's job.
it's an unreleased product which they were unable to buy
Sorry, you misspelled `too cheap to get an Apple'. Now with Boot Camp they don't even have the wold excuse that it won't run their warezed games in their warezed copy of Windows.
At first, Apple would sell fewer Macs, but many, many more copies of OS X.
Yeah, right. Again: those who are actually willing to pay for OS X are willing to pay the so-called `Apple premium' and get a real Apple.
A side issue: a version of OS X for generic PC is still going to need drivers, and lots of them. Where are these going to come from? I don't think we can count on OEMs to produce them, especially for even slightly older product, and it would be a monumental task for Apple to do it. Not my problem
Not Apple's problem either that you're too cheap to buy a Mac.
"I tried OS X on my old emachine and it failed to see my scanner, didn't work with the e-button on the case to launch internet explorer, and sleep never worked properly either -- no way I'm buying a crappy apple computer..." Why would they think the Apple computer is crappy, when it's their eMachine that sucks?
Maybe you should pay a visit to the real world some day and see how users actually behave, instead of how you think they should behave.
The sibling already addressed the first point (I wasn't aware that the similarity was Kubuntu specific, sorry).
As far as linux "catching up".. all depends on what you want to do with the system. It is a tool like any other system.
The OP specifically mentioned user friendliness and desktop quality. Anyone claiming KDE or Gnome is anywhere close to OS X has been blinded by fanboyism or is just plain practicing Orwellian doublethinking. And let's not even start on the quality of bundled applications, or the simplicity of installing an application on OS X (just drag it to the Applications folder), and so on. Apple is just years ahead and I seriously doubt that there is enough talent on desktop Linux projects to ever reach Apple's level (certainly in terms of designers there isn't).
Linux is shaping up to be better and better at being user friendly and desktop quality.
Yeah, right. They may be `shaping up', but it will take at least a decade before they reach the level of Apple in 2006. Never mind that they'll have to catch up with Apple's 2016 experience then.
That's from a former on-and-off Linux user since 1998, full time user since 2001, who switched to Macs in 2005 and isn't looking back in the least. I had to suffer (strong emphasis on suffer) Ubuntu for a couple of days in February, and I was reminded how painful Linux is and seriously wondered how I managed these four years as a Linux-only user. Windows is paradise in comparison. (Oh, by the way: I've never seen such blatant imitation as KDE's Control Center is of OS X's System Preferences. I actually laughed out loud the first time I saw it. I'll forever use it as an anecdote to characterize open source developers and their culture of imitation.)
Someone is going to do it eventually anyway. If apple wants to get any cash from PC's using their OS they will have no choice but to come up with a "real" version to conteract the hacked versions that are undoubtedly going to spring up on every torrent site sometime in the near future (if not already)
Right, because all the big OEMs like Dell install OSes downloaded from The Pirate Bay. Oh, they don't? But surely Joe Sixpack is competent enough to install a new OS and is even aware of the existence of OS X (and hacked OS X)?
Face it, whoever's installing OS X on a non-Apple computer is not Apple's target market anyway. They're not paying now and wouldn't pay if Apple released a legal version, just like they pirate Windows today.
Slashdot Mirror
Eh, go run an `openssl speed rsa' benchmark and see what kinds of results you get.
In my MacBook with a Core 2 Duo 2.4 GHz CPU, I get 30 RSA-2048 private-key operations per second, and 1042 public-key operations per second. One of these operations is used on every SSL handshake, not sure which of the two, so I can't really say whether performance is only `really bad' or `eye-poppingly awful'. Sure the performance drain would be a myth if we only used symmetric encryption, but key exchanges can only take place on an insecure channel if public-key encryption is used.
Performance on the client is irrelevant, it doesn't have to perform hundreds if not thousands of encryptions per second like the server does.
Since we're talking about phone bugs, here's one I had to fight with for a while...
Lots of users are having problems with the GPS functionality on the iPhone 3G/3GS (see e.g. here). No apparent pattern there, but in Brazil, lots of users from one specific carrier were having GPS problems, and the beginning of these problems coincided with the start of Daylight Savings Time in Brazil. My iPhone, as well as my girlfriend's, are with this carrier and were experiencing the problem. Those with unlocked phones report trying other carriers' SIM cards and had GPS working again, but once you popped back the problematic carrier's SIM card, the GPS was dead again.
This nearly drove me nuts as I paid an obscene amount of money for the TomTom app and couldn't get it to work, so keeping up with the engineer spirit, I tried to debug the problem myself. I observed an interesting fact: there's a Clock app on the iPhone with a World Clock pane, and if I added a clock from any time zone, including my own, it was off by one hour. However the iPhone's main clock, shown on the top of the screen, was showing the right time. Eventually I discovered that if I restored my phone as a brand new phone (not restoring from backup) the GPS would work fine and world clocks would be fine... until you reboot the phone. After rebooting, the GPS is gone again and the world clock is off by one hour again.
Now you might ask what the time has to do with GPS. A lot, it turns out. GPS works by triangulating your distance from the satellites in the GPS constellation, which depends on knowing the exact position of the satellites. Since their orbits are corrected every so often, you must rely on so-called ephemeris data from each satellite, which is the required information to compute fairly exact orbits, and is updated fairly often (Wikipedia says GPS receivers should update ephemeris data every 4 hours). Originally this data is broadcast by the satellites themselves in their navigation message, at an awfully slow rate of 50 bits/s. You read it right, bits, not bytes or KB or MB, that's bits. As the navigation message is 1500 bits long, it takes at least 30 seconds to download it, which is about the time most standalone GPS receivers take to get a fix from a cold start (i.e. with stale ephemeris data). To work around this delay, most phones with GPS use the assisted-GPS variety, which downloads ephemeris data from a faster channel such as the cellular network. My theory is that some WTF-worthy excuse for an engineer at the carrier decided that, rather than doing time zone updates the right way, by updating configuration files to point to the new time zone, he'd just rather adjust the clock forward by one hour. The GPS chipset probably works with time zone neutral clocks so it asks for (say) UTC time and gets it off by one hour, and then computes the satellite orbits as though it were one hour later than it actually is. Obviously this means the triangulation computations go horribly wrong and rather than reporting something absurd, the chipset just pretends it couldn't get a fix.
It took a lot of complaining from a lot of people (to the carrier and to the government agencies responsible for telecommunications), but the carrier finally fixed the problem. However, it was a nightmare trying to deal with clueless customer support representatives who didn't try in the least to help (and probably were thinking all along `what does this wacko think GPS has to do with DST?'), just blindly suggesting that we restore the phone, or even try to uninstall the built-in Maps app, or blaming it on Apple and saying they weren't responsible -- and never mind that unlocked phones with SIM cards from other carriers worked fine, and that the iPhone support situation is unique in Brazil as Apple outsourced support to the carriers themselves. In the end, the customer support WTFs would be worth another post of its own, at least twice the size of this one.
But
No, one of them actually succeeds.
(This post brought to you courtesy of the Well-Ordering Principle.)
For orientation (knowing where the Wii-mote is pointing), you pretty much need a gravitational field, since that's a fixed reference: it always points down. In a microgravity environment (or freefall), the Wii just wouldn't know where it was pointing since there's no reference to compare to. Of course, if you need attitude control in a microgravity environment, say a satellite or space station, then you can use other types of sensors, such as gyroscopes (which measure angular acceleration `on their own' and are insensitive to linear acceleration, including gravity).
Another interesting type of sensor, at least if you're on the surface of the earth, are magnetometers. They're a bit harder to calibrate, since the orientation of the earth's magnetic field is not constant across the surface of the earth, but once calibrated, they provide another fixed reference in addition to accelerometers. Assuming rotations only, and since magnetic and gravity fields are generally not aligned, you can solve the `blind axis' problem; even if you have a rotation in an axis aligned either to the magnetic or gravity fields, it won't be aligned to the other field, so you'll be able to sense it. The problem with translations isn't solved yet though; I'll try to illustrate. Let's pretend the magnetic and gravity fields are perpendicular to each other; still, if you consider the orientation of, say, the magnetic field, there's still a whole plane of vectors perpendicular to it, and any one of those could be a valid acceleration vector. So you have your shiny magnetometer-enabled Wii-mote, and apply a rotation to it in the same plane as the gravity vector should be; the addition of these two vectors is a third vector in the same plane, and could easily be mistaken for the gravity vector itself. There's just no way to decompose these back into the gravity and external force components.
Tell me about it. I was trying to use readouts from my MacBook Pro's accelerometers to implement a positioning demo, but what I saw on the screen was just completely uncorrelated to the actual movements. I tried to apply some simplistic filtering schemes but as expected they weren't successful. Oh well, I never did actual inertial engineering work, I only did interfacing and instrumentation work for an inertial engineering project, so I only know the basics of the subject, certainly not the advanced algorithms required to obtain useful data from inertial sensors. I'm actually very impressed from what I read about the Wii -- they seem to have done a very good job, certainly much better than what we achieved in our lab.
I believe you mean having a second accelerometer aligned to a different axis. Unfortunately, that doesn't add any extra information; you're still measuring the same physical quantity. Think of this as reading a vector in a canonical coordinate system (say x = (1,0,0), y = (0,1,0), z = (0,0,1)), and then reading the same vector but in a rotated coordinate system; these two are equivalent if you were to apply a certain change of base matrix (a rotation matrix, to be specific), so the second readout will not give you any new information.
Come to think of it, if you were to position the accelerometers in two distinct points of the Wii-mote, then I _think_ (but don't quote me on that) that rotations about non-symmetric axes (i.e. an axis not equidistant to both accelerometers) would give different readouts on each of them. I assume someone much smarter than I am could deduce information about the rotation axis and angle from this information, but I certainly can't think of how. When I said I did some inertial engineering work, this was an undergraduate project and I was just responsible for some interface and instrumentation systems, not the core inertial engineering stuff. What I learned about inertial engineering proper was about summed up on the grandparent post.
Having done some inertial engineering work, I can shed some light on this issue.
The Wii-mote has accelerometers on it. These sense forces applied to it (gravity included), and their combined output is a vector indicating the direction and modulo of the resultant acceleration. Assuming you're standing still, you'd only be subject to the force of gravity, and by definition it always points to the ground. So do a few vector computations and you know the orientation of the Wii-mote. There is a problem with a `blind axis' (rotation in the same axis as gravity can't be detected), but ignore that for now.
On the other hand, if you want to estimate position, here's what you have to do: given an initial position, read the accelerometers, subtract the effect of gravity from the acceleration vector (harder than it seems, since the Wii-mote could be pointing anywhere, really), which then gives the `real acceleration' of the system. Now integrate this once to obtain velocity, and again to obtain position. There's just so much room for error here, that I don't know where to start. Limited accelerometer resolution, poor A/D converters, temperature drift, numerical accuracy issues, you name it. Integrating measurements (not only that, but integrating twice!) is just a recipe for disaster. Then there's a fundamental limitation to accelerometer devices: rotations can't really be distinguished from translations. Just think about it -- a given resultant acceleration vector could be the result of pointing the Wii-mote in any given orientation, added to a specific acceleration in a specific direction. You just don't have enough information to distinguish between the two -- not with accelerometers alone, at least.
Hope that helps.
Oh, and the turbo button actually slowed down the processor down to the speed of a 4.7 MHz 8086. When in turbo mode the computer would run at nominal speed.
This is just the perfect story for me to plug my latest research, a couple of crypto protocols to help ensure P2P users behave honestly when uploading and storage rewards of some kind are involved, and there exists the incentive to cheat. Hope someone puts them to good use.
Clippy pops up in the corner...
`It looks like you have cancer. Would you like to book a session of radiotherapy?'
Fact is, I've become so used to incoherent, pointless, misspelled, gramatically incorrect, factually incorrect, stream-of-conscionouss postings in Slashdot, that it just never occurred to me this one might be any different.
Really? Please prove it. I couldn't find definitive prove for or against it, but here's from the FAQ in the official site: Initial discussions have been held with China, India, Brazil, Argentina, Egypt, Nigeria, and Thailand. (emphasis mine on two African nations, although what I meant by Africa in my post was miserable places in general, but I was expecting pedantry just the same).
Outside of you 31337 sphere of influence, 99.9% of people will think of DSL as Digital Subscriber Line, if anything. I'll gladly assume that I take pride in being`ignorant' on this case, as opposed to a mindless Linux fanboy who hijacks popular acronyms for their obscure stuff and expects everyone to follow.
Yeah, I'm pretty sure the miserable kids nearly dying of hunger in Africa (remember, that's the kind of people this project is targeting) have the money laying around to pay for DSL, assuming it's even available in their region.
War is peace, freedom is slavery, ignorance is strength, right?
I don't live in the US so one of the first things I did was disable iTMS. I completely forgot about iTMS as far as iTunes is concerned.
Maybe it's the fact that my Mac is a bit underpowered (G4 1.42 GHz, 4200 RPM HD). Nah, can't be, Linux and open source is the best choice for old machines, as I hear practically every day from slashbots. I cringe at the thought of running OpenOffice at anything with less than 2 GHz of clock and 1 GB RAM. (Off-topic, I know, but couldn't resist.)
The fact remains that Safari is very efficient. In fact, whenever I use a Windows machine, I'm moving away from the habit of installing Firefox and just running IE (even if Firefox is installed), since it's so goddamned slow.
Why yes, I did. Let's start... the File->Open File... dialog is about as scary as the advanced options of a BIOS screen would be to a newbie. Open the preferences screen, there's hundreds if not thousands of options. I recall having problems playing movies with certain WMV codecs, which of course Flip4Mac runs just fine.
Overall, when I was switching, I had a choice between standard Quicktime (no Pro then) and VLC/MPlayer. Coming from Linux I was actually used to the latter. I couldn't help the fact that I was drawn to Quicktime and currently I only have VLC here as a relic. Quicktime is good enough to me and has that Apple quality which no open source app can achieve, let alone surpass.
News to me (and I used Amarok before switching to the Mac). The most remarking memory I have of it was how often it crashed -- I don't recall iTunes ever crashing on me. Anyway, why do you claim that? Because it plays some obscure format no one cares about?
I could start on how it doesn't take half a minute to load, and 15 seconds to be swapped back from the HD whenever I've been away from it for a while, like Firefox does. Then there's the `Apple polish' which is never present on any open source app, even when they try to imitate Apple (since they always mess some details).
Quicktime standard is fairly crippled, but I have no complaints about Quicktime Pro. It is certainly much better than the garbage media players available for Linux. Also, I can encode small and good quality video without wading through hundreds of KBs of man pages for weird commandline compression options (*cough*mencoder*cough*).
Considering I didn't specify which Mac I have (a mini which I paid US$ 700 for about a year ago), nor how often I upgrade it (I'm saving to buy a Macbook Pro on 2H 2006, for a 1.5-year upgrade cycle, I'll just have to say that you don't know what the fuck you're talking about. I could pay my bills and save the rest for like 4 months and be able to afford the Macbook Pro in question.
Sure, anything you're not used to will be unfriendly at first sight. Give it a week before you issue an opinion. That was about the time it took me to get used to the new menu bar placement when I switched to OS X. Now, being experienced with both menu bar styles, I can state that I find OS X's approach superior.
I can't even try out Eclipse, I only have a meager 512 MB of RAM which can't accomodate wasteful Java applications (running Azureus is enough of a chore). Xcode is good enough for my needs. Also, some believe iWork to be superior to the bloat of OpenOffice, and those that don't can always run it on OS X. And then there's the non-cheap types, which instead of using MS Office clones like OpenOffice, would rather run MS Office directly. Both of these options (iWork and MS Office) are available on OS X but not Linux.
But these weren't the applications that I was thinking of. How about Safari vs. Konqueror (or even the bloat of Firefox? I keep Firefox here for the couple of sites which don't work correctly with Safari, but I'd really hate to use it as my main browser), how about iTunes vs. XMMS or Amarok or whatever, Quicktime vs. MPlayer/Xine, and then there's the iLife suite (Garageband, iPhoto, iDVD,
There's lots of shipping software for OS X... maybe you're just too incompetent for the task?
Ah, I see, Java programmer. It makes sense now.
Neither have I. I live in an `emerging' country and barely make US$ 1k/month (and Apple hardware is more expensive, not cheaper, where I live). Yet I am aware of how much extra productivity a Mac affords me, so I save money to buy Apple hardware since it pays itself off in the long run.
If you live in a developed country, you probably do, much more than I. Unless you're one of those people who max out their credit cards and can't afford to pay the bill and keep paying interest for the rest of life (I guess if I was that way I wouldn't have bought my Apple, but luckily I'm financially responsible). Maybe buying an Apple is not your priority; if you don't work with computers, that's justifiable. In my case I couldn't afford the lack of productivity due to staying with Linux or even Windows, so I was practically forced to switch.
I guess your original computer cost $0 since you're not taking its cost into account. Anyway, the next time you upgrade, consider getting a Mac, which comes with OS X for free, won't cost much more and will have much higher quality than your current PoS Dell or self-built computer. Otherwise keep drooling over OS X, because Apple sure as hell won't let you run it in anything else but its own hardware.
I always thought open source developers took pride in the quality and `innovation' (God, I hate that word) of their software, not market economics. Guess that explains a lot of things.
So why don't you pony up for a real Apple computer to get the real Apple experience? Don't tell me you have some Windows apps you need to run, Boot Camp already took care of that excuse.
Wow, you sure have an impressive crystal ball! Not only have you predicted the scenario but also exact sales figures!
Wait, you didn't happen to pull these figures out of your ass, did you? You seem like a pretty good candidate for John Dvorak's job.
Sorry, you misspelled `too cheap to get an Apple'. Now with Boot Camp they don't even have the wold excuse that it won't run their warezed games in their warezed copy of Windows.
Yeah, right. Again: those who are actually willing to pay for OS X are willing to pay the so-called `Apple premium' and get a real Apple.
Not Apple's problem either that you're too cheap to buy a Mac.
Maybe you should pay a visit to the real world some day and see how users actually behave, instead of how you think they should behave.
The OP specifically mentioned user friendliness and desktop quality. Anyone claiming KDE or Gnome is anywhere close to OS X has been blinded by fanboyism or is just plain practicing Orwellian doublethinking. And let's not even start on the quality of bundled applications, or the simplicity of installing an application on OS X (just drag it to the Applications folder), and so on. Apple is just years ahead and I seriously doubt that there is enough talent on desktop Linux projects to ever reach Apple's level (certainly in terms of designers there isn't).
Yeah, right. They may be `shaping up', but it will take at least a decade before they reach the level of Apple in 2006. Never mind that they'll have to catch up with Apple's 2016 experience then.
That's from a former on-and-off Linux user since 1998, full time user since 2001, who switched to Macs in 2005 and isn't looking back in the least. I had to suffer (strong emphasis on suffer) Ubuntu for a couple of days in February, and I was reminded how painful Linux is and seriously wondered how I managed these four years as a Linux-only user. Windows is paradise in comparison. (Oh, by the way: I've never seen such blatant imitation as KDE's Control Center is of OS X's System Preferences. I actually laughed out loud the first time I saw it. I'll forever use it as an anecdote to characterize open source developers and their culture of imitation.)
Right, because all the big OEMs like Dell install OSes downloaded from The Pirate Bay. Oh, they don't? But surely Joe Sixpack is competent enough to install a new OS and is even aware of the existence of OS X (and hacked OS X)?
Face it, whoever's installing OS X on a non-Apple computer is not Apple's target market anyway. They're not paying now and wouldn't pay if Apple released a legal version, just like they pirate Windows today.
Is this an attempt to prove the saying that if a lie is often repeated, it becomes true?
Intel First to Ship Dual core
I don't care how you spin it, your statement was a lie bordering on AMD fanboyism.