Apple patent involves distributing files across a network
Posted by Dennis Sellers 
May 8, 2008 at 12:05pm
Apple has filed a patent (number 20080106517) at the U.S. Patent & Trademark Office for a method and apparatus for distributing computer files across a network. The invention relates to the process of distributing files to computer systems. More specifically, the present invention relates to a method and an apparatus for efficiently distributing computer files from a server to multiple clients across a network.
According to Apple, one embodiment of the present invention provides a system for distributing files across a network. During operation, the system receives a request at a server to download a file to a client. If the server is not currently downloading the file, the system commences a download stream for the file on a multicast port. If the server is currently downloading the file, the system remembers a marked location on the file, wherein the marked location relates to a current packet number of the download stream on the multicast port. The system then continues downloading the file until the end of the file, thereby allowing the client to receive the remainder of the file. Next, the system downloads the file from the beginning of the file to the marked location, thereby allowing the client to receive previously transmitted portions of the file.
Here’s Apple’s summary of the invention: “One embodiment of the present invention provides a system for distributing files across a network. During operation, the system receives a request at a server to download a file to a client. If the server is not currently downloading the file, the system commences a download stream for the file on a multicast port. If the server is currently downloading the file, the system remembers a marked location on the file, wherein the marked location relates to a current packet number of the download stream on the multicast port. The system then continues downloading the file until the end of the file, thereby allowing the client to receive the remainder of the file. Next, the system downloads the file from the beginning of the file to the marked location, thereby allowing the client to receive previously transmitted portions of the file.
“In a variation of this embodiment, if the server receives an additional request from a second client to download the file, the system updates the marked location in the file to the current packet number in the download stream. The system then continues to download the file until the end of the file, thereby allowing the second client to receive the remainder of the file. Next, the system downloads the file from the beginning of the file to the marked location, thereby allowing the second client to receive previously transmitted portions of the file.
“In a further variation, when the system receives a notice from the client at the server that a specified packet was not received, the system inserts the specified packet into the download stream.
“In a further variation, if notices are received from multiple clients that the specified packet was not received, the system inserts the specified packet into the download stream only once to satisfy the notices.
“One embodiment of the present invention provides a system for receiving files across a network. The system operates by sending a request from a client to a directory server for a network address for a file server. In response to the request, the client receives an address for the file server and a multicast address for a file stream. The client then requests a download of the file from the file server and subsequently receives the file stream at the multicast address.
“In a variation of this embodiment, the client remembers the number of the first received packet in the file stream. If the first received packet is not the first packet in the file stream, the client reserves space in a local file for the previously transmitted portions of the file—from the first packet in the file up to the first received packet in the file stream. The client then receives and stores data from the file stream into the local file. When the end of the file stream is reached, the client continues to receive and to store the previously transmitted portions of the file from the first packet in the file up to the first received packet.
“In a further variation, if a missing packet is detected in the file stream, the client sends a retry request to the server to resend the missing packet. The client then monitors the file stream for the missing packet. If the missing packet is received, the client stores the missing packet in the local file. Otherwise, the client resends the retry request to the file server after a specified period of time has elapsed.”
The inventors are Minoru Taoyama and Arthur de la Cueva Truong. The graphic below illustrates clients and servers coupled to a network in accordance with an embodiment of the present invention.
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Contributor
Dennis Sellers
Dennis has been a newspaper editor/reporter (seven years) and teacher (seven years). He has over 4,000 magazine, newspaper and online articles to his credit. He has also covered the Mac and tech industries for over a decade for such online publications as MacCentral, MacMinute and now MacsimumNews.
G Says:
Always appreciate learning about these kinds of things.
One problem with recent patent articles - you now seem to write about the products in your ‘own words’, then you say “Here’s Apple’s summary of the invention” and repeat exactly the same words.
Not very useful - or am I missing something!?
Posted on May 11, 2008