Add to that, about 10-20% of the population get motion sick using the kind of VR in Oculus Rift (myself included - I can use it for 2-5 minutes, depending on the mode). It's ludicrous to imagine building a school that would exclude 20% of the potential pupils on some random criterion. You might as well make schools that didn't let in gingers...

Apple already ships 64-bit ARM chips and a lot of other vendors are racing to do so. The Android manufacturers that I've spoken want 64-bit for the same reason that they want 8-core: It's a marketing checkbox and they don't want to be shipping a 32-bit handset when their competitor is marketing 64-bit as a must-have feature. ART is in the top 10 worst-written pieces of code I've had to deal with and is full of casts from pointers to int32_t (not even a typedef, let alone intptr_t), but it should get a 64-bit port soon.

64-bit is here for a while. A lot of modern '64-bit' CPUs only support 40-bit physical addresses, so are limited to 'only' 128GB of RAM. Most support 48-bit virtual addresses (the top bit is sign extended, so all 1 or all 0 depending on whether you've got a kernel or userspace address), limiting you to 'only' 32TB of virtual addresses. If RAM sizes continue to double once every year, then it takes another year to use each bit. We currently have some machines with 256GB of RAM, so are using 41 bits. 64 bits will last another 23 years. RAM increases have slowed a bit recently though. 10 years ago, you always wanted as much RAM as possible because you were probably swapping whatever you were doing. Now, most computers are happy with 2GB for programs and the rest for buffer cache. As SSDs get faster, there's less need for caching, but there might be more need for address space as people want to be able to memory map all the files that they access...

Huh? It's in the Google Play Market and is no harder to install than any other app. Once it's installed, the first time you click on a link from another app you're asked to choose the app that will handle links. I fall into the geek category (and so installed it from F-Droid, not Google Play), but found it trivial to switch to Firefox on the mobile. I mostly did because Chrome has spectacularly bad cookie management and I'd been trying to find a browser that did it better. Early Firefox ports were as bad, but now it's quite nice and with the Self Destructing Cookies add-on does exactly what I want.

The mobile is actually the only place I use Firefox...

I recall reading some years ago that there are two kinds of atheists:

• Those that disbelieve all religions.
• Those that disbelieve all except one religion.

For some reason, people in the second category describe themselves as 'religious'. And yet you'll be hard-pressed to find, for example, a Christian who requires the same standards of evidence for the non-existence of the Norse, Egyptian, Greek or Hindu gods as he requires that an atheist from the first category provides for the non-existence of the Abrahamic god.

How about 'tablet'? Coming through Heathrow security, I get told to take laptops, iPads, and Kindles out of my bag. I guess any brand of laptop has to come out, but tablets and ebook readers only do if they're made by Apple or Amazon...

No, I'd rather that copyright on music and video be contingent on distribution in a form that does not lock customers into a particular platform.

Talking about open-source businesses is missing the point entirely. Most businesses that are successful as a result of open source (or Free Software, for the RMS-style folks) or that contribute significantly to open source are not 'open-source businesses' any more than companies that use Windows and Office are 'closed-source businesses. The difference is that one category of businesses realises that writing software is expensive and copying software is trivial, so spends its investment on the software parts of its infrastructure paying people to write software (typically customising and improving existing projects), whereas the other pays someone for copies of software and hopes that that will give them an incentive to produce software that's more like they want.

Not really. The kind of situations where Windows 3.x let you try to continue, Windows NT just handles transparently. In Windows 3.x, with cooperative multitasking, a single application can refuse to relinquish the CPU. If this happens, you have three choices (outlined by the dialog box):

• Just wait and see if it eventually recovers.
• Kill that application and hope that it isn't holding any handles that other processes need to be able to do useful work.
• Restart the entire computer.

In a system with protected memory and preemptive multitasking, an application that refuses to relinquish the CPU will just have its priority downgraded and the only thing that you'll notice is the CPU getting warm. Eventually, you may choose to kill the program, but it never affects system stability.

It means that there's a high probability that something has damaged some kernel data structures. If you continue, there's a good chance that this corruption will spread to the buffer cache and you'll end up writing invalid data to disk. If you kill the system, the corruption is limited to the RAM.

Agreed on Chen's blog, but the summary is horrible. This message hasn't been part of Windows since Windows 95 (which introduced preemptive multitasking to the Windows world, so a single application could no longer freeze the system trivially), so the odds are that if you used Windows in the last two decades you've never seen this notice...

The idea is to have a timer that would automatically disable the equipment unless it received an enable signal, either from a satellite or removable medium. It's possible to make such a system that is, at the very least, very difficult to tamper with. Many of the systems on tanks and so on are computer controlled and if the computers stop working then it's a lot less valuable. The goal of such systems is similar to that of crypto: it's not to prevent the enemy from ever using the tanks that they've stolen, it's to prevent them using them quickly. If you have a few weeks to bomb the stolen equipment before it can be used, and the enemy has to invest a lot of high-tech resources into cracking the systems, then that's probably good enough.

MIRVs are a better second-strike weapon. In a first-strike context, your missile bases are all working fine and you can just launch everything that you've got at the enemy. MIRV in a first strike requires fewer missiles to get through, but that just means you need to build fewer missiles, which doesn't reduce the cost by a huge amount compared to the cost of maintaining a first-strike capability at all. In a second-strike situation, however, you're much more likely to have limited launch resources (a few submarines if you're late, the missile silos that you can contact in time if you're not). Being able to have a devastating second-strike capability with just one submarine surviving is a strong deterrent.

You didn't read my post, did you? You can turn it off globally, but it's really hard to then turn it on for a subset of applications. You have to individually disable each one's access (and they all default to 'on', so you have to remember to do it again after installing each new app). If I turn on mobile data somewhere expensive to look something up urgently (or, for example, to get an updated boarding pass for a flight) then suddenly a dozen applications will say 'whee, Internet! Let's download a load of updates!'

If you're doing a million items, then the difference between O(N) and O(N^2) is a factor of a million. If each operation takes one cycle to complete, then on a 2GHz CPU you're going to take 500 microseconds. More plausibly, if each iteration takes 10 cycles, then it will take 5ms. The O(n^2) version, assuming the same ten-cycles per operation (which is pretty small - even a bubblesort on integers in an array will be hard pressed to be that quick), will take one hour and 23 minutes.

If you really think that the difference between 5ms and almost an hour and a half is irrelevant, then I really hope that I never use any code that you write.

De Morgen's laws are widely known and trivial to automate. Any vaguely modern compiler knows about them and will do the transform for you. Not only will it do it for you, it will do it for you everywhere and base on knowledge of the target architecture.

That said, it won't rearrange things that might have side effects. In C, for example, you have short-circuit evaluation, so if you have something cheap on the left of an or and something expensive on the right, then it will be faster unless the compiler can determine that the expensive thing has no side effects. If you have a negation of a long string of ands, the arguments to each of which is expensive to compute, then turning it into a string of negated ors is faster, because the compiler can stop computing once it's found one that's failed.