Afaict provided they aren't for too high a percentage of the houses value mortgages are generally regarded by the banks as low risk so even in places where they don't have tax relief for mortgage interest they are still generally the cheapest way for an individiaul to borrow.
For audio stuff non-storage scopes are fine. Because when troubleshooting audio you would typically put a repetitive test signal in (or if you are building a synthisyser make it generate one).
For microcontroller work however you really want to be able to look at a fairly complex waveform. If you try this with a traditional scope even if you can arrange for it to be repetitive (which is sometimes quite difficult) the scope is likely to keep triggering at different poitns in the waveform. So you really want a device that can take a signal hit of a waveform and store it. Analog storage scopes do exist but I haven't personally used one so can't comment on how good they are. Also you will be dealing with higher frequency signals (a PIC18F running at it's max clock speed can toggle an IO at about 5MHz, other processors can do it much faster)
From the qualifications listed in the original request I get the impression that this guy is planning to do stuff with microcontrollers etc. If he is planning to stick with pic level stuf he will probablly be able to get away with one of the cheap chinese scopes, beyond that something better is needed.
Afaict Lecroy are generally regarded as the top brand in scopes but with a price tag to match with agilent (former HP) and tek taking up the middle of the range and the far eastern vendors covering the crappy end of the market.
Personally I find traditional non-storage analog scopes pretty much useless for digital stuff. Really you can only use them if you can arrange for the signal in question to output a simple pattern that repeats infinitely.
Never used an analog storage scope but from what I hear they aren't exactly great for high speed stuff either.
One exception: if you can stretch your budget to get a used TDS3000 or TDS3000B series scope, that would be a good way to go. There is one listed on ebay buy it now right now for the original posters budget of $2000
The problem is the forces involved with a spinning disc get much worse with diameter.
The moment of inertia of a cylinder (of constant thickness and density) is proportional to the fourth power of the diameter. Afaict (read: i'm trying to do calculus in my head here) the centripetal force required to hold the cylinder together is proportional to the cube of the diameter and proportional to the square of the angular velocity (spin speed).
You could but it would create a couple of serious complications.
1: You'd probably want the whole platter at the same temperature as a thread 2: moisture would be a menace so you would have to have the platters running in dry air. That would mean you would have to either come up with some system for drying air that went through the equalisation vent or completely seal the drive case (hard drives are not sealed because of they were air pressure changes would put huge stress on the case).
I doubt you coudl easily get the air dry enough to avoid condensation problems with a simple filter so I suspect you would either want a pressure case or a bladder.
I think you could probablly build such a drive to fit in a 5.25 inch bay and maybe a 3.5 inch bay but I very much doubt you'd get it in a laptop (which is the area where drive capacity issues bite most acutely)
The biggest problem with HDDs is that while sustained read speeds have been going up a bit and capacities have been going up a lot transactions per second has been sitting pretty still. You can't get away from the fact that it takes time to physically move the heads and then wait an average of half a rotation for the data to be under them.
Increasing the rotation speed works to some extent but there are big heat problems with that.
Now tell me exactly how I can do that with a few SSD's Well you can get 1TB SSDs, you should be able to get 8 of them in one machine relatively easilly if you buy the right case and maybe add one extra controller. The cost is indeed pretty insane though (I make it about $25K for 8x1TB drives)
Personally for desktops and servers I think a mixture is the way to go. SSD for things that get heavy random access (e.g. the OS and apps) and HDD for everything else. Even with a fairly heavy app load system drives don't generally need to be massive. Unfortunately for laptop users most laptops either only support one HDD or require you to sacrifice the optical drive to add a second HDD.
Given that HDDs in underventilated cases sometimes reach 60 or so and you want some safety margin it sounds like you'd want one that would work up to 80 or so.
So while I think 100 is higher than needed it's not completely out of whack.
The Vertex 2 Pro is up to 240 gigs for under $700. Wasn't long ago that the tiniest, crappiest-performing SSD cost that much. Now that's the price of the biggest and fastest. I can't comment on fastest but it's far from the biggest. You can get 512GB and 1TB SSDs (though the 1TB ones are desktop form factor) now but the price is insane.
In another year, the $/gig ratio will be even better along with performance. I sure hope so
Right, that would explain why some form of signal is needed and even why they might want to introduce new voltages to indicate new levels of charge avilability but making chargers that work fine with the older iphones not work with the latest model smalls like a pure money grab to me.
mmm at least in the UK trams don't tend to share the road with cars. Sure they cross roads and sometimes run along them for short sections but for the most part they run along dedicated routes.
Dell are pretty good about this afaict. They provide proper install CDs (not recovery crap) and the bios keying only checks the machine is a dell. The OS and driver CDs are seperate (though I belive they may integrate some AHCI/RAID drivers in the OS cds they certainly don't integrate a full set of drivers).
In my opinion its not much of an effort to simply burn the driver directory on to a cd or dvd It isn't that much of an effort but it's easy to overlook. Especially given that every manufacturer does it differently.
The drivers aren't generally that big an issue since as you say you can usually get them from the manufacturers website. The problem is windows. If you are a tech (either employee or contracted) for a company that has a volume lincese and the volume license either covers the machine or reimage rights apply then it's not an issue because you just reinstall with your volume license media and key.
The problem comes if you have to reinstall machines for home users or small buisness who don't have volume licenses. You can't just go using your own keys on machines you aren't going to control (both for legal and practical reasons). Sometimes you can reinstall from a generic windows CD and activate but while that works for some people others report refusals to accept the key or activation problems after doing so.
Most people either can't understand or don't want to be bothered with managing thier own keys so real encrypted communications used by normal people relies on central authorities that either decrypt (and possibly reencrypt) the communication or at least manage the keys and connections between the users.
Who that central authority is makes a huge difference to how easy it is for the governement to subvert communications. If the authority is the phone network then it's easy, "wiretapping" arrangements are almost certainly already in place. If it's in thier country but not run by a telco they can probabblly force the operator to cooperate but it may take some effort. If the authority is in a foreign country then things are likely to be even harder.
Personally I like what dell does with thier buisness machines. The discs they ship (at least the XP ones, I haven't tried the vista or win7 ones) are windows install CDs (not "recovery CDs") that use the normal windows installer, don't insist on wiping the hard drive, don't seem to install andy crapware and yet provided you install them on a dell they will install without any activation BS.
Automation helps to some extent, I very much doubt a project like debian could support the number of ports it does without the array of software and infrastructure they have for autobuilding.
But that alone is not sufficient, a group of porters who care about bringing an architecture up to the coverage level required to become a release architecture and who have the skills to get it there is also needed.
Once a port reaches the status of release architecture things get easier for the porters because one of the requirements for getting a new version of a package into testing is that it builds successfully on all release architectures (exceptions can be made but generally only will be if there is a very good reason) it has built on before but still active porters are needed to keep an architecture viable.
Gasoline at least cuts out the middle man, by allowing fairly direct use of the energy of burned fuel. However small internal combustion engines are horribly inefficiant. Plus they only deliver usable power and efficiancy and can't deliver torque at stall at all so a complex drivetrain is needed to go between the car and the wheels.
IF the electricity is coming from CCGT plants then i'd expect the increased efficiancy of the power plants over an internal combustion engine to make up for the transmission, distribution and storage losses. Coal power plants are less efficiant but coal-oil conversion isn't exactly efficiant either.
The best pursuit out there is that of a hydrogen powered vehicle, that runs with water as it's fuel. Umm making water into hydrogen would use up more energy than you would get from burning it so it's only worth it if you are storing the hydrogen (essentially using it as a form of battery).
Well what would you like to do.. you mention Windows, iOS and Android, sadly all three of these platforms have different "best languages Afaict if you want to write the core of your code (obviously you will have to rewrite the UI for each) in a way that is portable across those platforms and more then the best option is to write that core in either plain C or "C with classes" style C++.
In the UK they are card happy (whether it be Debit or Credit) and has moved more and more to a cashless and chequeless society, That hasn't been my experiance in the UK. Round here (near Manchester) most smaller places (conviniance stores, non-chain fast food places) either won't take cards or will only take them for purchases over a certain value. I'm also pretty sure bus drivers don't take card payments.
Cheques mainly seem to be used for paying tradesmen and similar.
What I always found helped most with a graphic calculator was not the graphing functionality (which I used fairly rarely) but the screen size.
I found being able to check what I was typing and look back at the last few calculations made it far easier to avoid mistakes.
On older non-graphic calculators you could only see the value you were typing at the time and didn't see anything much when you pressed the operators. More modern ones are better but still show a lot less than graphic ones.
Afaict the problem isn't so much those who actually figure out new and inventive ways to cheat (who as you say probablly didn't need to cheat in the first place) as those that reuse others cheating systems.
Nah - iirc, it's opensource, meaning that if need be, MySQL's development will be reconstituted under other leadership. That's true however postgresql is much freer than mysql. In particular mysql's client access libraries are under the GPL (with a few exceptions, e.g. for php). So if you want to write propietry apps against it (either now or in the future) you need a license that only oracle can sell you. IIRC at one point they were even trying to claim the GPL applied to the wire protocol.
It's not an issue for php webapps but it's certainly something to consider if you think your database may ever need to be accessed in other ways or if you are learning a DB with the intention of using it in many future projects.
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Afaict provided they aren't for too high a percentage of the houses value mortgages are generally regarded by the banks as low risk so even in places where they don't have tax relief for mortgage interest they are still generally the cheapest way for an individiaul to borrow.
For audio stuff non-storage scopes are fine. Because when troubleshooting audio you would typically put a repetitive test signal in (or if you are building a synthisyser make it generate one).
For microcontroller work however you really want to be able to look at a fairly complex waveform. If you try this with a traditional scope even if you can arrange for it to be repetitive (which is sometimes quite difficult) the scope is likely to keep triggering at different poitns in the waveform. So you really want a device that can take a signal hit of a waveform and store it. Analog storage scopes do exist but I haven't personally used one so can't comment on how good they are. Also you will be dealing with higher frequency signals (a PIC18F running at it's max clock speed can toggle an IO at about 5MHz, other processors can do it much faster)
From the qualifications listed in the original request I get the impression that this guy is planning to do stuff with microcontrollers etc. If he is planning to stick with pic level stuf he will probablly be able to get away with one of the cheap chinese scopes, beyond that something better is needed.
Afaict Lecroy are generally regarded as the top brand in scopes but with a price tag to match with agilent (former HP) and tek taking up the middle of the range and the far eastern vendors covering the crappy end of the market.
Personally I find traditional non-storage analog scopes pretty much useless for digital stuff. Really you can only use them if you can arrange for the signal in question to output a simple pattern that repeats infinitely.
Never used an analog storage scope but from what I hear they aren't exactly great for high speed stuff either.
One exception: if you can stretch your budget to get a used TDS3000 or TDS3000B series scope, that would be a good way to go.
There is one listed on ebay buy it now right now for the original posters budget of $2000
http://cgi.ebay.com/Tektronix-TDS3014-Digital-Oscilloscope-100MHz-w-HPIB-/300450756657?cmd=ViewItem&pt=BI_Oscilloscopes&hash=item45f442b831
The problem is the forces involved with a spinning disc get much worse with diameter.
The moment of inertia of a cylinder (of constant thickness and density) is proportional to the fourth power of the diameter. Afaict (read: i'm trying to do calculus in my head here) the centripetal force required to hold the cylinder together is proportional to the cube of the diameter and proportional to the square of the angular velocity (spin speed).
You could but it would create a couple of serious complications.
1: You'd probably want the whole platter at the same temperature as a thread
2: moisture would be a menace so you would have to have the platters running in dry air. That would mean you would have to either come up with some system for drying air that went through the equalisation vent or completely seal the drive case (hard drives are not sealed because of they were air pressure changes would put huge stress on the case).
I doubt you coudl easily get the air dry enough to avoid condensation problems with a simple filter so I suspect you would either want a pressure case or a bladder.
I think you could probablly build such a drive to fit in a 5.25 inch bay and maybe a 3.5 inch bay but I very much doubt you'd get it in a laptop (which is the area where drive capacity issues bite most acutely)
The biggest problem with HDDs is that while sustained read speeds have been going up a bit and capacities have been going up a lot transactions per second has been sitting pretty still. You can't get away from the fact that it takes time to physically move the heads and then wait an average of half a rotation for the data to be under them.
Increasing the rotation speed works to some extent but there are big heat problems with that.
Now tell me exactly how I can do that with a few SSD's
Well you can get 1TB SSDs, you should be able to get 8 of them in one machine relatively easilly if you buy the right case and maybe add one extra controller. The cost is indeed pretty insane though (I make it about $25K for 8x1TB drives)
Personally for desktops and servers I think a mixture is the way to go. SSD for things that get heavy random access (e.g. the OS and apps) and HDD for everything else. Even with a fairly heavy app load system drives don't generally need to be massive. Unfortunately for laptop users most laptops either only support one HDD or require you to sacrifice the optical drive to add a second HDD.
Given that HDDs in underventilated cases sometimes reach 60 or so and you want some safety margin it sounds like you'd want one that would work up to 80 or so.
So while I think 100 is higher than needed it's not completely out of whack.
The Vertex 2 Pro is up to 240 gigs for under $700. Wasn't long ago that the tiniest, crappiest-performing SSD cost that much. Now that's the price of the biggest and fastest.
I can't comment on fastest but it's far from the biggest. You can get 512GB and 1TB SSDs (though the 1TB ones are desktop form factor) now but the price is insane.
In another year, the $/gig ratio will be even better along with performance.
I sure hope so
Right, that would explain why some form of signal is needed and even why they might want to introduce new voltages to indicate new levels of charge avilability but making chargers that work fine with the older iphones not work with the latest model smalls like a pure money grab to me.
mmm at least in the UK trams don't tend to share the road with cars. Sure they cross roads and sometimes run along them for short sections but for the most part they run along dedicated routes.
Were these consumer machines (inspiron/studio/xps) or buisness machines (vostro/latitude/optiplex/precision)?
Dell are pretty good about this afaict. They provide proper install CDs (not recovery crap) and the bios keying only checks the machine is a dell. The OS and driver CDs are seperate (though I belive they may integrate some AHCI/RAID drivers in the OS cds they certainly don't integrate a full set of drivers).
In my opinion its not much of an effort to simply burn the driver directory on to a cd or dvd
It isn't that much of an effort but it's easy to overlook. Especially given that every manufacturer does it differently.
The drivers aren't generally that big an issue since as you say you can usually get them from the manufacturers website. The problem is windows. If you are a tech (either employee or contracted) for a company that has a volume lincese and the volume license either covers the machine or reimage rights apply then it's not an issue because you just reinstall with your volume license media and key.
The problem comes if you have to reinstall machines for home users or small buisness who don't have volume licenses. You can't just go using your own keys on machines you aren't going to control (both for legal and practical reasons). Sometimes you can reinstall from a generic windows CD and activate but while that works for some people others report refusals to accept the key or activation problems after doing so.
This is where encryption comes in.
Most people either can't understand or don't want to be bothered with managing thier own keys so real encrypted communications used by normal people relies on central authorities that either decrypt (and possibly reencrypt) the communication or at least manage the keys and connections between the users.
Who that central authority is makes a huge difference to how easy it is for the governement to subvert communications. If the authority is the phone network then it's easy, "wiretapping" arrangements are almost certainly already in place. If it's in thier country but not run by a telco they can probabblly force the operator to cooperate but it may take some effort. If the authority is in a foreign country then things are likely to be even harder.
Personally I like what dell does with thier buisness machines. The discs they ship (at least the XP ones, I haven't tried the vista or win7 ones) are windows install CDs (not "recovery CDs") that use the normal windows installer, don't insist on wiping the hard drive, don't seem to install andy crapware and yet provided you install them on a dell they will install without any activation BS.
Automation helps to some extent, I very much doubt a project like debian could support the number of ports it does without the array of software and infrastructure they have for autobuilding.
But that alone is not sufficient, a group of porters who care about bringing an architecture up to the coverage level required to become a release architecture and who have the skills to get it there is also needed.
Once a port reaches the status of release architecture things get easier for the porters because one of the requirements for getting a new version of a package into testing is that it builds successfully on all release architectures (exceptions can be made but generally only will be if there is a very good reason) it has built on before but still active porters are needed to keep an architecture viable.
Gasoline at least cuts out the middle man, by allowing fairly direct use of the energy of burned fuel.
However small internal combustion engines are horribly inefficiant. Plus they only deliver usable power and efficiancy and can't deliver torque at stall at all so a complex drivetrain is needed to go between the car and the wheels.
IF the electricity is coming from CCGT plants then i'd expect the increased efficiancy of the power plants over an internal combustion engine to make up for the transmission, distribution and storage losses. Coal power plants are less efficiant but coal-oil conversion isn't exactly efficiant either.
The best pursuit out there is that of a hydrogen powered vehicle, that runs with water as it's fuel.
Umm making water into hydrogen would use up more energy than you would get from burning it so it's only worth it if you are storing the hydrogen (essentially using it as a form of battery).
Well what would you like to do.. you mention Windows, iOS and Android, sadly all three of these platforms have different "best languages
Afaict if you want to write the core of your code (obviously you will have to rewrite the UI for each) in a way that is portable across those platforms and more then the best option is to write that core in either plain C or "C with classes" style C++.
In the UK they are card happy (whether it be Debit or Credit) and has moved more and more to a cashless and chequeless society,
That hasn't been my experiance in the UK. Round here (near Manchester) most smaller places (conviniance stores, non-chain fast food places) either won't take cards or will only take them for purchases over a certain value. I'm also pretty sure bus drivers don't take card payments.
Cheques mainly seem to be used for paying tradesmen and similar.
While the two posts say essentially the same thing they don't appear to be direct copies.
What I always found helped most with a graphic calculator was not the graphing functionality (which I used fairly rarely) but the screen size.
I found being able to check what I was typing and look back at the last few calculations made it far easier to avoid mistakes.
On older non-graphic calculators you could only see the value you were typing at the time and didn't see anything much when you pressed the operators. More modern ones are better but still show a lot less than graphic ones.
Afaict the problem isn't so much those who actually figure out new and inventive ways to cheat (who as you say probablly didn't need to cheat in the first place) as those that reuse others cheating systems.
Nah - iirc, it's opensource, meaning that if need be, MySQL's development will be reconstituted under other leadership.
That's true however postgresql is much freer than mysql. In particular mysql's client access libraries are under the GPL (with a few exceptions, e.g. for php). So if you want to write propietry apps against it (either now or in the future) you need a license that only oracle can sell you. IIRC at one point they were even trying to claim the GPL applied to the wire protocol.
It's not an issue for php webapps but it's certainly something to consider if you think your database may ever need to be accessed in other ways or if you are learning a DB with the intention of using it in many future projects.