Identifying and requesting data in network using identifiers which are based on contents of data
First Claim
Patent Images
1. In a data processing system, an apparatus comprising:
- identity means for determining, for any of a plurality of data items in the system, a substantially unique identifier, said identifier depending on all of the data in the data item and only on the data in the data item; and
existence means for determining whether a particular data item is present in the system, by examining the identifiers of the plurality of data items.
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Abstract
In a data processing system, a mechanism identifies data items by substantially unique identifiers which depend on all of the data in the data items and only on the data in the data items. Existence means determine whether a particular data item is present in the system, by examining the identifiers of the plurality of data items.
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Citations
53 Claims
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1. In a data processing system, an apparatus comprising:
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identity means for determining, for any of a plurality of data items in the system, a substantially unique identifier, said identifier depending on all of the data in the data item and only on the data in the data item; and
existence means for determining whether a particular data item is present in the system, by examining the identifiers of the plurality of data items. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method of identifying a data item in a data processing system for subsequent access to the data item, the method comprising the steps of:
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determining a substantially unique identifier for the data item, said identifier depending on all of the data in the data item and on the data in the data item; and
accessing a data item in the system using the identifier of the data item. - View Dependent Claims (31, 32, 41, 42, 43, 44, 45, 48, 50, 53)
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33. A method for duplicating a given data item from a source location to a destination location in a data processing system, the method comprising the steps of:
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determining a substantially unique identifier for the given data item, said identifier depending on all of the data in the data item and only on the data in the data item;
determining, using said data identifier, whether said data item is present at said destination location; and
based on said determining, providing said destination location with said data item only if said data item is not present at said destination. - View Dependent Claims (34, 37, 39)
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35. A method for determining whether a particular data item is present in a data processing system, the method comprising the steps of:
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(A) for e tech data item of a plurality of data items in the systems (i) determining a substantially unique identifier for the data item, said identifier depending on all of the data in the data item and only on the data in the data item; and
(ii) making and maintaining a set of identifiers of said plurality of data items; and
(B) for the particular data item, (i) determining a particular substantially unique identifier for the data item, said identifier depending on all of the data in the data item and only on the data in the data item; and
(ii) determining whether said particular identifier is in said set of data items.
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36. A method of backing up, of a plurality of data items, data items modified since a previous backup time in a data processing system, the method comprising the steps of:
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(A) maintaining a backup record of identifiers of data items backed up at the previous backup time; and
(B) for each of said plurality of data items, (i) determining a substantially unique identifier for the data item, said identifier depending on all of the data in the data item and only on the data in the data item;
(ii) determining those data items of the plurality of data items whose identifiers are not in the backup record; and
(iii) based on said determining, copying only those data items whose data identities are not recorded in the backup record.
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38. A method of locating a particular data item at a location in a data processing system, the method comprising the steps of:
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(A) determining a substantially unique identifier for the data item, said identifier depending on all of the data in the data item and only on the data in the data item;
(B) requesting the particular data item by sending the data identifier of the data item from the requestor location to at least one location of a plurality of provider locations in the system; and
(C) on at least some of said provider locations, (a) for each data item of a plurality of data items at said provider locations, (i) determining a substantially unique identifier for the data item, said identifier depending on all of the data in the data item and only on the data in the data item; and
(ii) making and maintaining a set of identifiers of data items, (b) determining, based on said set of identifiers, whether the data item corresponding to the requested data identifier is present at said provider location; and
(c) based on said determining, when said provider location determines that the particular data item is present at the provider location, notifying said requestor that the provider has a copy of the given data item.
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40. A method of locating a particular data item among a plurality of locations, each of said locations having a plurality of data items, the method comprising the steps of:
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determining, for the particular data item and for each data item of the plurality of data items, a substantially unique identifier for the data item, said identifier depending on all of the data in the data item and only on the data in the data item; and
determining the presence of the particular data item in each of said plurality of locations by determining whether the identifier of the particular data item is present at each of said locations.
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46. A method of eliminating a data item at a given location in a data processing system when said data item can be obtained from another location in the system, the method comprising the steps of:
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determining a substantially unique identifier for the data, said identifier depending on all of the data in the data item and only on the data in the data item;
making and maintaining a source association between the data identifier and at least one location at which said data item is known to be present; and
based on said source association, if said data item is present at said other location, removing the data item from the given location.
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47. A method of deleting a data item from a location in a data processing system, the method comprising the steps of:
for each of a plurality of data items in the system;
determining a substantially unique identifier for the data, said identifier depending on all of the data in the data item and only on the data in the data item; and
making and maintaining, an association between each of the data items and the unique identifier of the data items; and
for a given data item;
determining a substantially unique identifier for the data, said identifier depending on all of the data in the data item and only on the data in the data item; and
determining whether a contextual identifier or a compound data item or a remote processor in the system refers to the unique identifier of the data item, and based on said determining, deleting said data item and its association if no other contextual identifier or compound data item or remote processor refers to said data item.
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49. A method of substantially synchronizing data items at a client location in a data processing system after a period of independent changes on the client and another location in the system, given a context, the method comprising the steps of:
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making and maintaining a list of changes to the context association between each context name of a data item and the identifier of said data item, in the given context and during the period of independent change;
obtaining the list of changes from the other location for the given context; and
,for each context name in the list of changes updating the context identifier associations at the client whenever it is determined that the context association of the given context name changed either only at the client or only at the other location during the period if independent changes; and
performing a conflict-resolution task such as notifying an operator of the client location, whenever it is determined that the context association changed at both the client and the other location.
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51. A method of maintaining at least a predetermined number of copies of a given data item in a data processing system, at different locations in the data processing system, said data processing system being one wherein data is identified by a substantially unique identifier, said identifier depending on all of the data in the data item and only on the data in the data item, and wherein any data item in the system may be accessed using only the identifier of the data item, the method comprising the steps of:
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(i) sending, from a first location in the system, the data identifier of the given data item to other locations in the system; and
(ii) in response to said sending, at each of said other locations, (A) determining whether the data item corresponding to the data identifier is present at the other location, and based on said determining, and (B) informing said first location whether said data item is present at the other location; and
(iii) in response to said informing from said other locations, at said first location, (A) determining whether said data item is present in at least the predetermined number of other locations, and based on said determining, (B) when less than the predetermined number of other locations have a copy of the data item, requesting some locations that do not have a copy of the data item make a copy of the data item. - View Dependent Claims (52)
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Specification