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Comment Re:Scope creep (Score 1) 326

Or a less well-known but more catastrophic (and less excusable) example, the capsizing in a storm of the British sailing turret ironclad HMS Captain in 1870, in which nearly all aboard her drowned, almost 500 people. Among the victims was her designer, Captain Cowper Coles, an early advocate of warships with turreted main guns. Due to poor supervision during Captain's construction, she was about 10% heavier than planned, and since the design already sat low in the water and had limited stability, the extra weight proved to be her undoing.

Comment Re:why does your phone need software running on yo (Score 1) 519

Yes, this is indeed a known bug which I've encountered myself. In my case, the culprit was some free version of VMware. (Note that VMware is listed among the problematic software on the Apple support page linked to by the parent.) Uninstalling the VMware version solved the problem.

Comment i386 >> mini :) (Score 1) 256

(That ">>" in my subject is a "much greater than", not a right shift. :)

To me, the dividing line between a minicomputer and a microcomputer is the capability for virtual memory. Desktop computers have been architecturally minis since the 68030 and i386.

That's kind of funny to me, since the term "minicomputer" came into vogue in the later 1960s to describe computers like the original PDP-8 (the "Straight 8"). Far from being a virtual memory machine, the PDP-8 was a 12-bit architecture with a minimal instruction set and a very limited address space. Later PDP-8s used bank-switching to expand their addressable memory, as did the later 16-bit PDP-11. In many ways the early minis were architecturally similar to 8-bit and 16-bit microcomputers. Compared to them, the 80386 and 68030 look like ultra-powerful monsters.

Comment Re:I don't see much point in this (Score 1) 64

I think Twitter is a bit faster than that. Twitter users in Japan seem to respond really fast when they feel any moderate level of shaking; at times, if you follow enough Japanese people on Twitter, your entire timeline gets filled with people saying "oh hey, something's shaking" or "it's rocking" or "boobs!". So yes, you will get advanced warning if there are people closer to the epicentre than you posting on Twitter (and as long as they are not using a certain phone provider which got overloaded during the big earthquake/tsunami last year while all the other providers were fine). And yes, this obviously doesn't work if the earthquake knocks out all the cell phone infrastructure in the areas between you and the epicentre.

Amusingly enough, I was watching a UStream broadcast run by some Japanese guy and people from a different area of Japan told him that they just had an earthquake, and he replied saying he didn't get any info here. Then, several seconds later, the earthquake alarm went off in the broadcast. So, I think Twitter isn't going to be very far off in terms of speed and definitely should be able to inform you about an ongoing earthquake as long as it's not a super short one and you're like next to the epicentre.

Comment Re:For those who still don't get it (Score 1) 98

The analogy kind of works and kind of doesn't. A parallax barrier has an image layer and a fixed mask layer. What these guys did was to allow for multiple layers with time-varying patterns and optimize the pattern on each layer so as to create a better image. So it's more like "this is to integral what parallax on crack is to lenticular."

Comment Re:Holografika.com (Score 2) 98

The company website is scant on details of their technology, but it's obvious that a different implementation is used and my guess from what they do say is that it's a lenticular device that only generates horizontal parallax. In that case, try tilting your head 90 degrees to the side and you'll lose depth perception, whereas this wouldn't be the case for the tensor display mentioned in the article. It might not be that important of an issue, until you want to lie down on a couch and watch a 3D program on TV...

Comment Re:It's a tensor display. (Score 4, Informative) 98

Oh interesting, so they finally gave it a name. I remember coming across the 2-layer version of the display sometime ago. Looks like they also have an interesting theoretical foundation to go with it; the abstract of the first paper from Gordon Wetzstein's page gives a nice overview.

What essentially is going on is that you can model (at least when talking about things much larger than the wavelength of light) light as a four-dimensional function (i.e. intensity of light along all the possible rays that fill space), which is referred to in this research area as a "light field." Putting a mask somewhere in space will mask out a 2D-extrusion of the mask shape in 4D space. Putting multiple masks at different planes will mask out the product of this 2D-extrusions (and the extrusion angle varies as a function of depth). Hence, what they are doing is attempting to piece together the original 4D function by piecing together unmasked portions at each time frame.

For a more simplified view, you can think of this as trying to create a 2D picture through a sequence of special single-color 2D pictures created by placing stripe patterns oriented at a fixed set of angles on top of a light panel.

If you've taken linear algebra, it is somewhat like decomposing a matrix into a sum of rank-one matrices, except here each component needs to be positive (masks cannot create "negative" light).

Comment Re:Bad system design? (Score 2) 88

There's plenty of other stuff in there making up the total system weight: structural framework, power supplies, and of course the mercury delay line memories, which were basically big sealed tanks of mercury. It also seems to have had magnetic drum storage, another heavy component. And I doubt weight of the system was a major concern anyway, as long as the floor could support it.

Comment Re:Why did these require so much power? (Score 2) 88

Perhaps because the low-power tubes were considered unsuitable for computing applications? Vacuum tubes in digital switching circuits have quite a different workload from those used in radios as amplifiers. The low-power tubes may not have provided fast switching performance, or they may have been unreliable in switching circuits. I'd think that power usage was a secondary concern for the designers of these computers; reducing it would be nice, but not at the cost of speed or reliability.

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