Sun Microsystems, Inc.

Kendall Square Research Corporation

Fernando Oliveira

Mark A Kaufman

A digital data processing apparatus configured to selectively transfer data between a primary data storage element and an associated data file on a secondary data storage element. The apparatus includes a primary data storage element that stores data for access by one or more processes, as well as a non-volatile secondary data storage element. A directory stores attributes reflecting a state of one or more subsets of data in respective sets. During transfer of data between the primary data storage element and the secondary data storage element, the apparatus stores data corresponding to the attribute in a second file on the second storage element, in response to detecting the transfer and detecting the attribute indicates an atomic state corresponding to the first data.

Method and apparatus for paging data and attributes including an atomic attribute

A digital data processing apparatus has a primary data storage element that stores data for access by one or more processes, as well as a secondary data storage element, e.g., a disk drive, for non-volatile data storage. A paging mechanism selectively transfers sets of data between the primary data storage element and an associated data file on the secondary data storage element. A directory stores &ldquo;atomic&rdquo; signals, or bits, each reflecting a state of one or more subsets of data in respective sets. The paging mechanism includes a page-out element that stores data from a subset of a set to the associated data file. During paging, the page-out element responds to data in the subset which are associated with the atomic state (as indicated by the atomic bit) for storing to an associated status file on the secondary data storage element attributes of the paged data. Those signals can be, for example, the atomic bits themselves.

Method and apparatus for paging data and attributes including an atomic attribute for digital data processor

A digital data processing system and method with shared, distributed memory transfers data between corresponding data sets within memory. The digital data processing system includes a plurality of processing cells interconnected by a hierarchical network, at least some of the processing cells including a processor and a memory. Each memory provides storage space which is arranged in sets, with each set being capable of holding a plurality of data pages. At least one of the processing cells, as a first processing cell, includes a page distributor for determining when at least a first set in the associated memory has reached a predetermined storage commitment condition (for example, a filled condition). Under such a condition, the page distributor invokes a page-transfer element that selects a candidate processing cell from among the other processing cells and transfers one or more pages from the first set to a corresponding set in the candidate processing cell.

Method and apparatus for distributing data in a digital data processor

A digital data processing apparatus includes a processing element that executes a process for generating requests for access to mapped data in a memory element. The apparatus also includes a fork/checkpoint-signalling element that generates 'new-process signals' which delineate new time intervals. The apparatus responds to data requests generated by the process before the first new-process signal by accessing a requested datum as stored in a first set in memory. An address space manager responds to certain requests, e.g., for write access, in subsequent intervals for copying the requested datum from the most recent set in which it is stored to the current interval and, thereafter, accessing that copy. The manager responds to other requests, e.g., those for read-type access, by accessing the requested datum in the most recent set in which it is stored. A fork element can create a second process that initially duplicates a first one and can initiate generation of a new-process signal in connection with creation of the second process.

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Framingham, MA, United States of America

Fernando Oliveira