Constellation - Slashdot User

A Quantum Linear Equation Solver 171

Posted by kdawson on Friday December 05, 2008 @01:00PM from the traveling-salesman-gets-a-break dept.

joe writes "Aram Harrow and colleagues have just published on the arXiv a quantum algorithm for solving systems of linear equations (paper, PDF). Until now, the only quantum algorithms of practical consequence have been Shor's algorithm for prime factoring, and Feynman-inspired quantum simulation algorithms. All other algorithms either solve problems with no known practical applications, or produce only a polynomial speedup versus classical algorithms. Harrow et. al.'s algorithm provides an exponential speedup over the best-known classical algorithms. Since solving linear equations is such a common task in computational science and engineering, this algorithm makes many more important problems that currently use thousands of hours of CPU time on supercomputers amenable to significant quantum speedup. Now we just need a large-scale quantum computer. Hurry up, guys!"

Feds Target "Mongols" Biker Club's Intellectual Property 393

Posted by kdawson on Tuesday October 21, 2008 @08:49PM from the shirt-off-your-back dept.

couchslug writes in with a Reuters account of a Federal raid on a California-based motorcycle club, the Mongols, on charges "ranging from murder and robbery to extortion, money laundering, gun trafficking and drug dealing." The interesting twist is that the authorities are asking the courts to seize the IP of the biker club — specifically, their trademarked name "Mongols." "Federal agents and police in seven states arrested more than 60 members of the Mongols motorcycle gang on Tuesday in a sweep that also targeted for the first time an outlaw group's 'intellectual property,' prosecutors said. The arrests cap a three-year undercover investigation in which US agents posed as gang members and their girlfriends to infiltrate the group, even submitting to polygraph tests administered by the bikers ... [T]he name 'Mongols,' which appears on the gang's arm patch insignia, was trademarked by the group. The indictment seeks a court order outlawing further use of the name, which would allow any police officer 'who sees a Mongol wearing this patch ... to stop that gang member and literally take the jacket right off his back' ..."

Practical Reasons To Choose Git Or Subversion? 667

Posted by kdawson on Tuesday October 21, 2008 @03:13PM from the while-we're-at-it-do-you-like-vi-or-emacs dept.

markmcb writes "I develop Rails applications and recently followed my lemming herd and made the switch to Git after learning some of the practical advantages Git offers over Subversion. As I'm sure there are many die-hard Subversion fans in the Slashdot audience, I'm curious what your key reasons are for sticking with Subversion. If possible, I'd like reasons that apply to 'most of the time' as opposed to arguments based on obscure features that may get used only a few times ever."

Comment Executable Management (Score 1) 177

by Constellation on Wednesday July 12, 2006 @02:34AM (#15703696) Attached to: A Closed Off System?

You are indirectly referring to the concept of executable management. The central idea here is to only allow trusted programs to run on the system. Under such a scheme the kernel would have a list of allowed programs (and libraries) complete with MD5 hashs etc. (to establish a chain of trust). When a program is executed the kernel would calculate it's MD5 sum (and sums for anything else that is loaded into memory) and the calculated sum isn't on the list then the program is not allowed to run. Under this scheme the users could "install" anything that they want on the system, but if it's not approved it doesn't run.

While a system like this would keep "bad" software from running on the system it is not a silver bullet (nothing ever will be), as someone will find ways around it. For example using an exploit in an allowed application that is already running.

There are also a couple of big limitations here, or with any system with the restrictions that you are asking about. First someone has to keep a list of the allowed applications, an update it regularly. This should be someone like the corporate IT department, it doesn't make sense to put the burdon on the OS vendor as you want the minimum set of applications on your systems and the OS vendor want the maximum set. Secondly this completely breaks software development, for obvious reasons.

I don't currently know of any operating system that implements these features.

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