Abstract: A computer network comprises first and second computers, each having a recovery facility for recovering a two-phase commit procedure and a recovery log. The log comprises a log name log which stores the names of other logs involved in a commit scope and a sync point log which stores sync point phase information. The log names are exchanged prior to a request for sync point. If a failure occurs during sync point, each recovery facility in the commit scope again exchanges log names to verify that there was not a log failure since the prior exchange. Absent a log failure, the logs are used to recover from the sync point failure. Communication facilities are interposed between the first and second computers and include log name exchange tables which record the previous exchanges of log names between the first and second computers.

Abstract: In a computer system or process, sync point managers are distributed throughout each real machine for a plurality of execution environments, but all of the execution environments and sync point managers within one real machine share a common recovery facility and recovery log. A common recovery log is used by the recovery facility for all of the execution environments in the system. Different systems are interconnected by a communication facility and each has its own recovery facility and recovery log. A protected conversation can be initiated between the first and second execution environments in the same real machine, and the sync point managers within the respective execution environments coordinate the two-phase commit procedures associated with the protected conversations. A conversation manager within each real machine assists in routing the conversation between the first and second execution environments.

Abstract: A Space Management System for a Data Access System of a File Access Processor for servicing requests from a set of Application Support Processors, which can exist in a global network, with each Application Support Processor sharing access to data in files stored by the File access Processor. The File Access Processor manages access to a set of data files and information about files held in file directories, which allow for managing file collections, can relate to each other hierarchically, and may be shared. Each Application Support Processor also maintains therein an internal cache of file information to improve performance by reducing communications required with the File Access Processor for informatin about files. The File Access Processor provides the Application Support Processors with information for updating and maintenance of local caches of directory and file description information through a centralized accumulation and distribution of cache change notifications.