Avalanche A Mere Pebble In The Pool

    June 21, 2005
    WebProNews Staff

BitTorrent’s creator Bram Cohen says the Redmond-based software company is full of hot air.

Vaporware. Complete garbage. Mr. Cohen doesn’t hide his feelings when discussing a recent research paper from Microsoft touting the virtues of its experimental file sharing system called Avalanche.

Microsoft’s UK researchers at Cambridge have been working on an approach similar to Mr. Cohen’s BitTorrent technology. The two systems both use a swarming technique, where users who request a file simultaneously make that file available to other requestors.

BitTorrent speeds up the process of finding and downloading large files, like those of movies and software programs. Avalanche does the same thing. The Avalanche testers claim to have distributed a 4GB file to their testers in under a day.

But Mr. Cohen finds fault with the simulations Microsoft has performed. “Particularly worrisome for their proposed scheme is disk access,” he said in his blog.

“If the size of the file being transferred is greater than the size of memory, their entire system could easily get bogged down doing disk seeks and reads, since it needs to do constant recombinations of the entire file to build the pieces to be sent over the wire.”

One problem Microsoft has tried to address is the completion of a download. In file-sharing, the swarming technique that brings bits of a file to a system. The last, or rarest, bits, can be hard to find. Users may have to wait hours for their systems to retrieve that last piece.

Microsoft says it avoids that problem by coding all the pieces so that each piece is a linear combination of all the pieces. Download enough pieces of a file, and Avalanche can recreate the original file based on the information in those pieces.

David Utter is a staff writer for WebProNews covering technology and business. Email him here.