The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 19, 1995
Filed:
Mar. 23, 1994
Richard Dievendorff, San Jose, CA (US);
Chandrasekaran Mohan, San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A data processing system for the storage of persistent and non-persistent data in a queue, and a method for the storage of data which is required to survive a system failure (persistent data) and data which is not required to survive a system failure (non-persistent data) on a single queue, are disclosed. The method involves receiving persistent and non-persistent data to be stored in a queue, then marking the data in time sequence order, before storing the persistent data in a first set of data pages and the non-persistent data in a second set of data pages. Upon receiving a request for removal of data from the queue, both the first and second sets of pages are checked and the data is removed in time sequence order. A log is preferably created to enable recovery in the event of failure and restart of the queue. When receiving and removing persistent data to be stored in and to be removed from the queue, log entries are made of changes to the persistent data only. Before the receiving of the data, a table in space map pages is created indicating which pages available in storage are free, which are allocated for persistent data, and which are allocated for non-persistent data. After receiving data and removing data, the table is updated. In the event of a failure and restart of the queue, space map page table is scanned and updated to indicate that all pages containing non-persistent data are free.