38 posts • joined 30 Apr 2010
> You are quite right, you can't rebuild a 4TB single disk in minutes. It's utterly impossible.
It is entirely possible and reasonable. There are 2 ingredients here:
0. Parity declustering. In a parity declustered array, e.g., 8+2 RAID6 can be used to stripe data across a large number of drives, say, 100 (rather than 10, as in standard RAID). This means, that only a small fraction (10% in this example) of each drive has to be read during rebuild. See Holland's thesis (http://www.pdl.cmu.edu/PDL-FTP/Declustering/Thesis.pdf) for details.
1. Distributed spare. By allocating spare space on each device, a fraction of *total* array bandwidth can be used for rebuild. That is, the wider is the array, the faster is the rebuild.
The funny thing is that this technology is 20 years old.
Re: It is rather sad
I beg to differ. Fundamental Hellenistic heritage are not natural sciences, but humanities. And this was preserved through the entire history of the Roman empire and bootstrapped Renaissance. Homer and Plato were studied and commented all they way down (vide http://en.wikipedia.org/wiki/Gemistus_Pletho). And there was no need for Italian cities to re-establish trade: it was never broken. In fact up to 12 century, Naples, Amalfi, etc. were *part* of the empire, formally, politically and economically. Funny enough, Naples was even a staunch supporter of iconoclasm (if I still know my Gibbon).
It is rather sad
that people persist in this silly anachronistic nonsense started by the 18th century propaganda, which chose Byzantium as a strawmen monarchy. There was no need to keep the "knowledge": up until 1453, the continuous tradition of Hellenistic education and scholarship was maintained in the Roman empire and its capital---Constantinople. There was almost at all times cultural exchange between the empire and Western Europe (sometimes, alas, in the form of Crusades).
Re: Allô ?
But "parking" is already French: it stems from ye Old French "parc", so it just returned back home. Actually, about 75% of the modern English vocabulary is of Romance origin.
The wrath of Vril-ya!
> Turing's work is widely held to have shortened World War II...
How is that? Did they share decoded info with their Soviets allies, who did most of the fighting?
ARM is being pushed in the HPC space too: http://www.montblanc-project.eu/ And mainly for exactly the same reason: energy consumption. Megawatt per petaflop is too high.
Re: The historical accident of little-endian
Historically, numerals in almost all languages are little-endians from "thirteen" (3+10) to "five and twenty". Operations, like addition, are performed from least to most significant digits and the new digits are added at the most-significant side. It is unnatural to do this right-to-left in the otherwise left-to-write oriented writing system. Because of this, *one* often finds oneself in a pain of printing a column of numbers right-adjusted (the only reasonable way to do this, so that scale is immediately visible).
Compare this with another ridiculous right-to-left vestige: the mathematical notation for function composition: f(g(x)), so cumbersome that mathematicians composing functions a lot (e.g., in category theory) adopt notation from programmers and write "g;f". But that at least we can blame on bad vodka Euler had. Fibonacci and his ilk who gave us big-endian numBerals have no excuse.
PS: the argument about "starting with the biggest quantity" makes no sense, because Arabs, who invented the thing, read from right to left and hence start with the least significant digit. Which put no hindrance on Arabian mathematics.
Re: WotW a Western
Not to say that the War of the Worlds (1898) predates any Western by a comfortable margin and features no good guys.
> The irony is, Nero was actually a quite reasonable guy
Yes, go tell this to Seneca and others. Oh wait... you cannot.
Re: It's okay, they're French...
It's not Google, it's "Big Five": LLNL, LALN, LNNL, ORNL, ANL. Why do you think they need *exaflop/exabyte* systems?
"I" seems to stay
for "Intel" in "ISC13".
Nokia^WWodka --- connecting people
So it's "England" and "duty of an Englishman". Good that rumours about so-called "[Kingdom of] Great Britain" are only rumours.
Re: Mixed lessons from history?
> and maybe some Soviets
And a lot of British---Mig's were equipped with Rolls-Royce Nenes at the time (which Sir Stafford Cripps was all too happy to provide together with licences).
There can be no "divine anything font" in a society happily free from the bourgeois capitalist-imperialist state ideology of worshipping imaginary dead. Back to a drawing board, comrade!
Re: This doesn't make sense
Let's try a very rough back of the envelope estimation. Assuming that the network is fully utilised during compute phase, the IO phase would be at least as long as compute phase, because the total state of computation must be dumped at it is more data than exchanged during compute phase. Worse yet, IO phase cannot be overlapped with compute phase of another task, because they compete for the fully utilised network. Which means that even in the ideal state, when the storage system is so blazingly fast that it is the network which is the bottleneck of IO phase, the duty cycle of the system is less than 50%. A reason for a big lab administrator to have a heart attack. The system seems to be misconfigured.
This doesn't make sense
I am sorry. Peak "flops" are achieved during compute phase of cluster jobs, when the interconnect is mostly idle. The network is used during IO phase, e.g., to dump checkpoints. Having a larger flops capacity does not imply a faster network. More details about benchmarks are needed.
> What does it mean to “own” something when it’s stored on someone else’s cloud server and
> can be wiped, possibly erroneously, with the flip of a switch? This is not ownership in any
> traditional sense of the word.
You mean, like money in a bank?
Re: "But I still submit it's force majeur."
Your contracts must be quite old if they were agreed before War did exist.
Re: Edsger Dijkstra
Dijkstra participated in design and implementation of some of the most influential languages, including Algol-60, Algol-68 and Ada. He and Hoare made fundamental work in language semantics, typing, formal correctness and concurrency. To think that EWD reduced computer science to algorithms is... unbelievable. (Yes, I subscribe to his view about Basic and yes, I programmed in it. It was difficult to unlearn, but worth it, all happy memories notwithstanding.)
Re means Reiser!
Passive stupidity is even more of a problem.
Forth to the past
And I thought Spengler gave us at least another century before the West falls to that hue and cry style of populism. Incidentally, "Gen. Petraeus" sounds powerfully Roman.
to protest a restrictive government
In the past it were the pro-government organizations that ddosed LJ.
forget trips to distant galaxies
Why should we? They don't require faster than light travel as was known since around Lorentz times.
Isn't it a bit odd that,
> as president of a country, Medvedev is writing that the police ought to investigate the
> attack rather than phoning them up and insisting they look into it.
Right, a bit of friendly support from Albion is exactly what notorious Russian "telephone law" (http://www.law.wisc.edu/m/nmytc/telephone_law_and_rol.pdf) needs.
No, this is an "art"
group "Voina" ("War"). Incidentally, they also ended up in a jail (http://www.bbc.co.uk/news/world-europe-12645902).
In a frame of reference
attached to the centre of the Earth, the Sun does revolve around the latter. The real blow to the Russian education system is that shaken Olga still believes that there is _the_ frame of reference.
In other news
Codex Seraphinianus is still waiting for radiocarbon analysis.
he is going to invent reference counting next!
after he complained to the Kremlin
those are the key words, believe me. Nobody loves trouble-makers complaining over one's head.
490,000 civil service jobs slashed
Even Sir Humphrey would need an awful lot of tea-ladies to handle that.
Pictures on the Met site
Oh, I have seen this site, in fact, there seem to be an awful lot of them, with phones and prices too.
Perelman _refused_ the prize.
Paris, because she does not care about money too.
I am disappointed.
Where is a mandatory "Yes, Prime Minister!" reference?
the last minute rule
With all the due respect to (presumably) late Mr. Gray, that rule only worked in a rather narrow set of configurations. Realistically, servers, especially high end ones, are stuffed with as much memory as fits in them.
HP noting that VTB Bank in Russia ... to get a mix of Superdomes and Integrity blades running HP-UX
And now HP is under a bribery investigation in Russia (http://business.timesonline.co.uk/tol/business/markets/russia/article7098065.ece). A coincidence of course.
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