There is provided an apparatus and a method for virtual memory mapping and transaction management for an object-oriented data base system having at least one permanent storage means for storing data and at least one data base, at least one cache memory for locally storing data addressed by physical addresses, and a processing unit including means for requesting data utilizing virtual addresses to access data in the cache memory, means for mapping virtual addresses to physical addresses and means for retaining the cached data after the conclusion of a transaction. The apparatus and method further provide that data retained in the cache across transactions will often not need further translation, referred to as forward relocation. The ability to make cached data usable across a sequence of transactions often without requiring further translation, while also providing that the total working set size of this data may be much larger than what can fit into a client computer's address space at any one time is referred to as relocation optimization, and is the primary advantage of this method. The method makes use of a single queue containing elements representing managed entities (pages, address space bindings) which orders the entities roughly by recency of use, and recycles address space of the least-recently used bindings in a way that preserves the validity of bindings necessary for the proper function of the client application with minimal overhead.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority of U.S. provisional application Serial No. 60/126,103 entitled, "Method and Apparatus for Pointer Relocation Optimization for Virtual Memory Mapping and Transaction Management in a Database System" filed Mar. 25, 1999 by the present applicant.
Techniques for caching media data, including streaming media data, using content-sensitive identifiers. The content-sensitive identifiers enable a caching proxy or a caching server to unambiguously determine the version or contents of media data cached by the caching proxy for a particular data pointer or data reference (e.g., a URL) such that an appropriate version of the media data can be served to a requesting client system in an efficient and economical manner.
A delta pager maintains a database with atomic, isolated transactions. When a transaction seeks to make changes to the database, the delta pager stores the changes in write buffers, and applies the changes when intervening transactions do not literally or substantively change the state of the database relied upon by the transaction. The delta pager applies the changes to commit the transaction by conjoining the write buffers with the current state of the database to form a new data structure representing the state of the database. The delta pager coalesces write buffers to maintain efficiency, subject to snapshots the delta pager respects to preserve selected states of the database. The delta pager makes selected sections of the database durable by moving selected data to a durable store. The delta pager also provides cache objects between the durable store and current transactions to promote efficient access to data.
Systems and methods are described for replicating virtual memory translation from a target computer on a host computer, and debugging a fault that occurred on the target computer on the host computer. The described techniques are utilized on a target computer having a processor that has halted execution. Virtual to physical address translation data from the target computer is transferred to the host computer. The host computer utilizes the virtual to physical address translation data to access data pointed by virtual memory addresses that were used by the target computer, and then debugs a fault by accessing the data by reading the physical memory address on the host computer. After the virtual to physical memory address translation data have been acquired, they can be cached at the host computer.
Systems and methods are described for replicating virtual memory translation from a target computer on a host computer, and debugging a fault that occurred on the target computer on the host computer. The described techniques are utilized on a target computer having a processor that has halted execution. Virtual to physical address translation data from the target computer is transferred to the host computer. The host computer utilizes the virtual to physical address translation data to access data pointed by virtual memory addresses that were used by the target computer, and then debugs a fault by accessing the data by reading the physical memory addresson the host computer. After the virtual to physical memory address translation data have been acquired, they can be cached at the host computer.
Systems and methods are described for replicating virtual memory translation from a target computer on a host computer, and debugging a fault that occurred on the target computer on the host computer. The described techniques are utilized on a target computer having a processor that has halted execution. Virtual to physical address translation data from the target computer is transferred to the host computer. The host computer utilizes the virtual to physical address translation data to access data pointed by virtual memory addresses that were used by the target computer, and then debugs a fault by accessing the data by reading the physical memory address on the host computer. After the virtual to physical memory address translation data have been acquired, they can be cached at the host computer.
