Google Open Sources MapReduce compression

Google has pen sourced the compression library used across its backen infrastructure including MapReduce, its distributed number-crunching platform, and Big Table, its distributed database.

Aviable at Google Code under an Apache 2.0 license, the library is called Snappy, but Google says this is same library that was previously referred to as Zippy in some public presentations. as the names imply, the library's primary aim is speed. "It does not aim for maximum compression, or compatibility with any other compression library,"Google says. "Instead, it aims for very high speeds and reasonable compression."


Compared to the fastest mode of the popular zlib compression library, Google says, the C++-based Snappy is an order of magnitude faster in most cases (roughly ten times faster), but the compressed files are between 20 and 100 per cent larger. Running in 64-bit mode on a single core of a 2.26Ghz "Westmere" Intel Core i7 processor, according to the company, Snappy compresses at roughly 250MB/sec and decompresses at 500MB/sec.

Google says that the typical compression ratios are about 1.5x to 1.7x for plain text and about 2x to 4x for HTML. zlib in its fastest mode gives you 2.6x to 2.8x for plain text and 3x to 7x for HTML. " So if you want to save space, or want to compress once and decompress lots of times, use zlib (or bzip2, or�). But if you just want to cut down on your I/O, be it network or disk I/O, Snappy might be for you," says Google engineer Steinar Gunderson.

According to Gunderson, Snappy removes the "entropy reduction" step that characterizes zlib and other LZ-style compression libraries. "Most LZ-style compressors (including zlib) consist of two parts: A matching algorithm (recognizing repetitions from data earlier in the stream, as well as things like 'abcabcabcabc') and then an entropy reduction step (almost invariably Huffman or some version of arithmetic encoding)," he says. "Snappy skips the entropy reduction and instead uses a fixed, hand-tuned packing format."

This format, Gunderson says, affords "much less" CPU usage, and he says that Google has spent years fine tuning it. Virtually all of Google's online service run atop a uniform distributed infrastructure based on the proprietary Google File System (GFS), MapReduce, BigTable, and other platforms. This have been mimicked in the open source world by the Apache Hadoop project.

Source : http://www.theregister.co.uk

Microsoft's Novell patent pals return to SuSE's homeland

The Microsoft-led consortium of tech companies trying to hoover up nearly 1,000 of Novell's patents is back in business.
CPTN Holdings re-registered with German authorities on Wednesday, according to the website of the German Federal Cartel Office. Plans to create CPTN as a German entity were withdrawn in December 2010.

CPTN is buying 882 of Novell's patents in a deal with soon-to-be Novell-owner Attachmate. Apple, EMC, and Oracle are also members of CPTN, but it's helmed by Redmond.

The re-registration of CPTN in the homeland of Novell's SuSE Linux was picked up by patents watcher Florian Mueller, who also noticed Novell's stock price is up 2.8 per cent in the US. "Looks like a strong clearance rumor or some other very signficant news," he Tweeted Thursday.
It certainly can't be Novell's financial position that's driving up the stock price. The Attachmate deal is helping to stall sales, with Novell recently reporting a $17.9m loss for its fiscal first quarter, compared to a profit of $20.2m a year ago.
Could Novell's sale to Attachmate and related sale patents to CPTN be closing? When CPTN withdrew from Germany last year, Microsoft called the move a "purely procedural step necessary to provide time to allow for review of the proposed transaction."
The group actually stopped operations the day before OSI president Michael Tiemann lodged an official complaint with the Federal Cartel Office, asking regulators to investigate the sale of the patents.
CPTN registered in US on November 11, 2010, and it has apparently continued operation throughout.
Officially at least, both Attachmate's acquisition and the CPTN deal are on hold in the US until April 12 while the Department of Justice reviews them.


Source : http://www.channelregister.co.uk

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Lama Tidak Posting

Gan, lama tak jumpa disini. Kepada seluruh gan yang setia mengunjungi blog ini, teriam kasih banyak. Saya terus mengusahakan agar mengupdate blog ini, tapi saya terlalu sibuk mengurus blog baru saya. Sekedar promosi :D di negerihijau.com dan gamepcdownload.com telah saya launching beberapa waktu yang lalu.


Sayangnya, trafik masih sedikit dan saya berharap, ini akan terus dikembangkan. Kedepan,