Abstract: During backup of a database's data stored in individual files, it is not permissible for the data in the individual files to be altered, for reasons of consistency. For this reason, the files are blocked to altering access operations after a particular time during a backup operation. According to the invention, the backup operation is carried out in two parts. First, the files are transferred without there being any alteration block. A recording file is used to note files which are altered during transferring. These files are transferred again in a second part. During the second part an alteration block is required. It can be assumed that the number of files needing to be transferred in the second part is much smaller than the number of files needing to be transferred in the first part. For this reason, a significantly shortened alteration block is achieved.

Abstract: The invention relates to a method for assuring compatibility between the software units activated in partial computer systems (system A, system B) belonging to a distributed computer system, said software units each comprising their respective version of software codes and/or data. Once a compatibility test has established compatibility, a compatible non-activated software unit is activated on its partial computer system and the corresponding previously activated software unit is deactivated. The invention also relates to a method for securing data within a distributed computer system with several partial computer systems, for blocking access to the data, for securing common data and for deactivating the data access block are carried out according to the current status of the data securing option.

Abstract: During backup of a database's data stored in individual files, it is not permissible for the data in the individual files to be altered, for reasons of consistency. For this reason, the files are blocked to altering access operations after a particular time during a backup operation. According to the invention, the backup operation is carried out in two parts. First, the files are transferred without there being any alteration block. A recording file is used to note files which are altered during transferring. These files are transferred again in a second part. During the second part an alteration block is required. It can be assumed that the number of files needing to be transferred in the second part is much smaller than the number of files needing to be transferred in the first part. For this reason, a significantly shortened alteration block is achieved.