* Posts by Serguei Patchkovskii

6 posts • joined 17 Jan 2008

Crypto cadre cloud-cracks SHA-1 with just $75k of compute cost

Serguei Patchkovskii

Re: US$75K to rent 60 GPUs for two weeks?

: (2) You apparently have no idea how hard and how long it takes to accomplish step

Ah yes. Ad hominem is a time-honoured debating position here on El Reg.

These days, installing, configuring, and maintaining a small, 15-node, 60-GPU computing cluster is a task routinely accomplished in countless research groups around the world by science undergraduates with no formal IT qualifications whatsoever.

So yeah, I have no idea.

Serguei Patchkovskii

US$75K to rent 60 GPUs for two weeks?

That's over $1K per GPU. For about 2.5x times that, you can outright *buy* an equivalent system, using something like this little toy, taking less than 1/3rd of a rack overall:


I know electricity and space do cost money, but one should be able to make this work with far less than $75K per collision.


Apple drinks Putin’s Kool-Vodka, shoves Russians' iCloud data into Russia – report

Serguei Patchkovskii

Canada is only one of many

Actually, as usual with Canada, it depends.

Federally, the PIPEDA act does not require personal data to be stored within Canada.

However, British Columbia and Nova Scotia do require certain kinds of personal information to be stored within Canada [*]; Quebec and Alberta impose restriction on where some information may be stored which may be in practice equivalent to a geographic restriction [+].

[*] see http://www.thestar.com/business/tech_news/2013/08/16/does_it_matter_where_your_data_lives.html;

[+] http://www.servercloudcanada.com/2014/05/canadian-privacy-laws-canadian-cloud-primer-canadian-businesses/;

I am too lazy to look up the original references, but Michael Geist is usually well-informed and factually correct.


Canadians taking to spying on their spies

Serguei Patchkovskii

First past the post and voters' intent

"FYI Trevor, the Alberta NDP were voted in as a form of protest because of an odious sitting government, not because of any endorsement by the majority of the population of the NDP polices."

As a Canadian and a former Albertan, I think a correction is in order. The overwhelming majorities PC (and Socreds before them) used to get are an obvious byproduct of the first-past-the-post system, rather than a reflection the voters' intent. Let's take a look at the years of the PC rule in, shall we? I'll round the votes and sears percentages to the nears integers if you don't mind.

Year %seats %votes cast

1971 65 46

1975 92 63

1979 94 57

1982 95 62

1986 81 51

1989 71 44

1993 61 44

1997 76 51

2001 89 62

2004 75 47

2008 87 53

2012 70 44

So, for about half of their 44-year rule, the PCs in fact were in power -against- the express wishes of the majority of the population, and still had dictatorial-level majorities. Whatever Trevor says, the current NDP government in Alberta is also ruling -against- the express wishes of the majority of the Albertans, 59% of whom cast their votes against an NDP candidate. Even so, they command 63% of the seats.

Unfortunately, every party seems to recognize the unfairness of the situation when they are in opposition (and I expect PC will be no different). Once they get the power, their outlook magically changes (and I expect NDP to be no differect) - so it seems we are stuck with first-past-the-post, and the increasing voter apathy.


Boffins build super-accurate atomic clock

Serguei Patchkovskii


Actually, the original explanation in the article was quite accurate as popular science goes.

A "fermion" is any particle - elementary or otherwise - with a half-integer total angular momentum. (For an elementary particle, its intrinsic angular momentum is "spin"). Turning a fermion around any axis by 360 degrees changes the sign of it's wavefunction. If particle's wavefunction does not change upon a 360-degree rotation, it is called a "boson", and has an integer spin. The total intrinsic angular momentum of a particle has important consequences at sufficiently low temperatures: two (or more) bosons can occupy the same quantum state (or be at the same place if you will). Two fermions cannot.

Whether a compound particle, such as an atom or a molecule, is a fermion or a boson depends on two things: the spins of it's constituent parts, and the way these spins are added together, or "coupled". The way these rules work is that a compound particle containing an even number of fermions (and an arbitrary number of bosons) will be a boson. A particle with an odd number of fermion constituents (and again any number of bosons) will be a fermion.

Strontium has 38 electrons (spin-1/2 particles). In its ground state, all its electrons are "paired", so that their spins cancel out, and total electron wavefunction has integer (zero) angular momentum. Most of the isotopes of its nucleus also have an even number of particles of each type (protons and neutrons), and thus integer spin as well. However, Strontium-87, which has natural abundance of about 7% has spin 9/2. As a result, the Sr-87 atoms have half-integer total angular momentum, and are fermions.


Everex follows Asus Eee to announce 9in sub-notebook

Serguei Patchkovskii
Thumb Down

Eee PC CPU is NOT underclocked

In all your eee-PC articles, you keep saying that eee uses a 900 MHz Celeron M underclocked to 630 MHz. It does not - like every other mobile CPU, it is dynamically clocked, between 112 and 900 MHz depending on the current load. Just double-checked it on my 4G ...