Abstract: A mechanism is provided which allows transparent transaction processing to occur between distributed networks using the AIX or SNA protocols. The present invention will convert between the AIX standard of Two Phase Commit/Presumed Abort (2PC/PA) and the SNA standard of Two Phase Commit/Presume Nothing (2PC/PN). The Presumed Abort Protocol will optimize operations by reducing the number of messages between sites participating in the transaction, and the amount of transaction state information maintained at a site. Thus, any messages needed will be generated and transaction status information will be maintained in order to satisfy a Standard 2PC/PN protocol, when sites within a SNA network are participating in an AIX transaction. Further, the present invention will discard, or ignore any extraneous messages which are received while sites within an AIX network are participating in a SNA transaction.

Abstract: A method for implementing transaction-consistent resource recovery from catastrophic media failures in a single pass over a recovery log archive while permitting most UNDO log records to be discarded during log archiving. The media recovery procedure is based on a pseudo-crash recovery technique that simulates a system crash at a selected time by writing PSEUDO-RECOVERY records to the recovery log. Resource recovery is then performed by normal execution of the log archive records up to the most recent pseudo-crash followed by execution of the subsequent PSEUDO-RECOVERY records. The recovery log record execution procedures are compatible with the ARIES recovery method. One embodiment of this invention assumes that the recovery log records can be selected for archiving on the basis of a combination of record type and transaction identifier.