Accessing data in a data processing system

Abstract

A method, in a system in which a plurality of data items are distributed across a plurality of computers, includes, at a first computer in the network, (a) receiving from a requesting computer in said network, a request, the request including a specific name of a particular data item, wherein the particular data item comprises a particular sequence of bits, and wherein the specific name of the particular data item is based at least in part on the data comprising the particular data item, the specific name of the particular data item having been determined, at least in part, using a given function of the particular sequence of bits, wherein two identical sequences of bits have the same name as determined using the given function; and (b) causing said requesting computer to obtain at least a portion of said particular data item from a second computer in said network, said second computer being distinct from said first computer.

1 . A method, in a system in which a plurality of data items are distributed across a plurality of computers, the method comprising:
 at a first computer in the network,
 (a) receiving from a requesting computer in said network, a request, the request including a specific name of a particular data item, wherein the particular data item comprises a particular sequence of bits, and wherein the specific name of the particular data item is based at least in part on the data comprising the particular data item, the specific name of the particular data item having been determined, at least in part, using a given function of the particular sequence of bits, wherein two identical sequences of bits have the same name as determined using the given function; and 
 (b) causing said requesting computer to obtain at least a portion of said particular data item from a second computer in said network, said second computer being distinct from said first computer. 
   
     
     
         2 . The method of  claim 1  wherein the first computer does not have a copy of the particular data item. 
     
     
         3 . The method of  claim 1  wherein the first computer knows one or more locations of the particular data item. 
     
     
         4 . The method of  claim 1  wherein the first computer forwards the request to at least one other computer in said network. 
     
     
         5 . The method of  claim 4  wherein the at least one other computer includes the second computer. 
     
     
         6 . The method of  claim 1  wherein the given function comprises a function that produces a substantially unique value based on the data comprising the data item. 
     
     
         7 . The method of  claim 1  wherein the data item may comprise a file, a portion of a file, a page in memory, a digital message, a portion of a digital message, a digital image, a portion of a digital image, a video signal, a portion of a video signal, an audio signal, a portion of an audio signal, a software product, a portion of a software product, a data item identifier, or a sequence of identifiers for components of a compound data item. 
     
     
         8 . The method of  claim 1  wherein at least some of said computers communicate with each other using a TCP/IP communication protocol. 
     
     
         9 . The method of  claim 1  wherein the given function comprises a message digest function or a hash function. 
     
     
         10 . The method of  claim 1  wherein the given function comprises a function selected from: MD4, MD5, and SHA. 
     
     
         11 . The method of  claim 1  wherein the given function comprises a function that randomly distributes its outputs. 
     
     
         12 . The method of  claim 1  wherein said particular data item is a portion of a file, and wherein said first computer causes said requesting computer to obtain the particular data item from a location having a copy of the file. 
     
     
         13 . The method of  claim 1  wherein said requesting computer obtains the particular data item directly from the second computer. 
     
     
         14 . A method, in a system in which a plurality of data items are distributed across a plurality of computers, the method comprising:
 (A) at a first computer in said network,
 (a) receiving from a requesting computer in said network, a request, the request including a specific name of a particular data item, wherein the specific name of the particular data item is based at least in part on the data comprising the particular data item, wherein the particular data item comprises a particular sequence of bits, and the specific name having been determined at least in part as a given function of at least some of the sequence of bits, wherein two identical sequences of bits will have the same name as determined using the given function; 
 (b) identifying a second computer in said network, distinct from the first computer, that should have a copy of at least a part of the particular data item; and 
   (B) causing said requesting computer to obtain at least a part of said particular data item from the second computer.   
     
     
         15 . The method of  claim 14  wherein a data item may comprise a file, a portion of a file, a page in memory, a digital message, a portion of a digital message, a digital image, a portion of a digital image, a video signal, a portion of a video signal, an audio signal, a portion of an audio signal, a software product, a portion of a software product, a data item identifier, or a sequence of identifiers for components of a compound data item. 
     
     
         16 . The method of  claim 15  wherein said particular data item is a portion of a file, and wherein said first computer forwards said request to a location having a copy of the file. 
     
     
         17 . The method of  claim 15  wherein said requesting computer obtains the particular data item directly from the second computer. 
     
     
         18 . A method, in a system in which a plurality of data items are distributed across a plurality of computers, the method comprising:
 (A) at a first computer,
 (a) receiving from a requesting computer in said network, a request, the request including a specific name of a certain data item, wherein the particular data item comprises a particular sequence of bits, and wherein the specific name of the certain data item is based at least in part on the particular sequence of bits comprising the certain data item; 
 (b) identifying a second computer in said P2P network that should have a copy of the certain data item, said second computer being distinct from the first computer; and 
   (B) the second computer providing the certain data item to the requesting computer,   wherein the certain data item may comprise a file, a portion of a file, a page in memory, a digital message, a portion of a digital message, a digital image, a portion of a digital image, a video signal, a portion of a video signal, an audio signal, a portion of an audio signal, a software product, a portion of a software product, a data item identifier, or a sequence of identifiers for components of a compound data item, and   wherein the specific name of the certain data item is computed using an algorithm that applies a message digest function or a hash function to the particular sequence of bits comprising the contents of the data item.   
     
     
         19 . The method of  claim 18  wherein the second computer provides the certain data item directly to the requesting computer.