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That's surprising. I went there recently, and you aren't permitted to bring any electronic devices whatsoever - you have to leave them in a locker and then take a ~30 minute bus ride to the telescope.

They're also very strict about checking: you have to go through two different x-ray machines to check you didn't sneak any electronics through.


Perhaps the no-devices policy was introduced after the interference issues were encountered?


No, the no devices policy would have been there from the start, its as basic as forbidding open flames at a petrol station.

The need for X-ray machines due to tourists ignoring the ban is a more likely development.


Are those truly x-ray machines? Not just magnetic coils? Seems overkill and I'd object to being exposed to ionizing radiation just for the purpose of validating my claim that I don't carry any electronic communication devices.


It's actually a pretty standard setup in China anyway... Pretty much anytime you go onto an inter-city bus / train or into a crowded space (museum / exhibition centre) you will go through a metal detector and your bag through an x-ray machine. So it makes sense that they'd just use the standard setup that the local security company would be used to.


Most likely it's X-rays for your stuff and metal detectors to make sure you're not trying to smuggle anything past the X-ray machine.


No, it wasn't there from the start. The no electronics policy only started within the last two years. I know someone who has been there and has the pictures on her phone.


This does seem very interesting! Because of your comment I started reading the architecture document for the GreenArrays[0] chip, and it's totally different to anything I've seen: a network of processing units, and the whole thing without a clock anywhere!

I am interested what makes you say it "provides computational grunt comparable to an i7 for a few milliwatts" though - could you elucidate? Do you mean in terms of performance-per-watt?

[0]: http://www.greenarraychips.com/home/documents/greg/PB002-100...


> I am interested what makes you say it "provides computational grunt comparable to an i7 for a few milliwatts"

I've been quite interested in Green Arrays, but I'm quite sure that's basically nonsense. The Ga144 can do lots of interesting stuff, but comparing it with an i7 is ill adviced. If for no other reason than that you have to provide your own dram interface, while the i7 typically comes with that in the form of chipset support.

The Ga144 can do md5, but I'm not convinced that it can do it better or equivalently than 4/8 i7 cores: http://www.greenarraychips.com/home/documents/pub/AP001-MD5....

In short, I think such a claim is misbranding the Green Array chip, setting potential users up for disappointment and at the same time selling the chip short.


Interesting, it reminds me a bit of the game TIS-100[0], similar idea of an array of very simple units interacting by I/O ports, blocking until a read/write to another unit can complete. I didn't know there was a real architecture like that!

edit: It seems the transputer[1] was similar, hadn't heard of that either.

[0]: http://www.zachtronics.com/tis-100/

[1]: https://en.wikipedia.org/wiki/Transputer#Links


The transputer actually has a successor called the XCore[0], which is produced by XMOS. They're founded by the same fellow that came up with the transputer (David May).

It's a similar concept again - it's a multi-core chip for embedded applications, and the cores communicate using an on-chip network. Each core is like a regular CPU with a clock though - the GreenArrays approach seems to be completely asynchronous.

[0] http://xmos.com/


Seconded! This is a fantastic book. Be warned: the English translation of the sequel is not yet released (and you will want it).


I was lucky to get a mix of C, Java, and Haskell. Unfortunately (to my detriment) I totally ignored Haskell, and it didn't really click until I picked it up at the end of my degree out of curiosity- it really does help to clarify one's thinking.

I think teaching the motivation for learning it before beginning would have been better than just throwing it at freshmen, but I can't truly blame anyone other than myself.


I suspect it's meant to be negative (mass squared) rather than (negative mass) squared.


Correct. Tachyons appear in dynamical equations with imaginary masses, which, when squared, give negative "squared masses".


Where's your server? I also have issues tunneling to a UK based server


My experience is that routes to UK and Europe (at least to budget VPS providers) have high latency and often have low throughput. Try servers in Singapore, Tokyo or the USA. Even these vary in performance, depending on the peering arrangements in place. Try to find an overseas host with direct peering with PCCW or China Unicom.


Playing with the ports may help. Try 443 instead of 22


I'm not sure if this really addresses your argument, but China certainly doesn't have a limited labor supply... Quite the opposite


The comment being replied to specifies that blocking and building would be a beneficial activity for all countries to participate in.


Looks interesting. However, does the following not mean that it's not portable?

> Note that if Shen is not running on a Lisp platform, then function may be needed to disambiguate those symbol arguments that denote functions.


It means that to be portable you have to wrap symbols that represent functions in (function <the-symbol>) when passing them as arguments. Not doing so will work on some ports but not on others, and should be considered "undefined behaviour".

Portable:

(foldl (function +) 0 [1 2 3])

May work depending on the backend:

(foldl + 0 [1 2 3])


I chose between Go and Haskell for a project some time around 2012. I was a beginner to both, but came from a background of imperative languages (C, C++, Java, etc.)

Initially I felt the same as you: Go was much easier to get things done in, and I could be reasonably productive quite quickly (moreso than Haskell, which I found very difficult to learn).

However, after some time I found many of the same problems mentioned in this article. Particularly, in many cases I had to fall back to the kind of nasty unsafe code mentioned in this article (like using interface{}). Often, I felt that my code was needlessly verbose. I would frequently write code and feel that the language was preventing me from doing what I wanted directly. Ironically, this is exactly how I felt with Haskell at first (not anymore).

Ultimately, I ended up switching to Haskell, and although it was significantly harder to learn, I felt like it has a lot more flexibility, safety, and importantly lends a clarity to thinking when designing a program.


This sounds strikingly similar to my experience! Though my imperative language experience was mostly with dynamic and/or scripting languages aside from C#.


Hate to be "that guy", but that should read "And Lo! ..."

http://english.stackexchange.com/questions/38741/use-of-and-...


much obliged.


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