Abstract: An information processing system providing archive/backup support with privacy assurances by encrypting data stored thereby. Data generated on a source system is encrypted, the key used thereby is separately encrypted, and both the encrypted data and encrypted key are transmitted to and maintained by a data repository system. The repository system receives only the encrypted data and key, while the source system retains the ability to recover the key and in turn, the data. The source system is therefore assured of privacy and integrity of the archived data by retaining access control yet is relieved of the physical management of the warehousing medium.

Abstract: A database of known commercial software programs ("Products") is maintained and employed as a template for selection of files for a backup operation. In particular, files which are part of known Products may be excluded during backup operations. Records indicating rules about which files within Product directories are included and excluded from the backup operation are also maintained in the database. Product directories may be determined from a registry or the hard disk may be scanned and directories checked against a list of known Product default directories. If the newly found directory does not match an entry in the list of default directories, then file list codes in the database are checked against the files in the directory to determine whether known Product files are present in the directory. Two types of exclusion commands are employed to identify files for exclusion from the backup operation by exploiting file creation and modification dates.

Abstract: File comparison employs a single function F to calculate a digital signature from data in a sliding window. The digital signature is both incrementally computable and position sensitive. In particular, F is computable without reprocessing each byte in the array when the window is advanced and facilitates detection of such changes as transposed bytes of data. The function F is defined by two qualities. First, for F(A+B), where A is an array, F(A+B)=F(A)+F(B). Second, given a concatenation operator "!" such that "0!A" indicates an array A with 0 inserted before A, the function F has the property that there is a function G such that F(0!A)=G(F(A'0)). Both polynomials and cyclic redundancy checks ("CRC") may be used as that class of function.

Abstract: A information processing system providing archive/backup support with privacy assurances by encrypting data stored thereby. Data generated on a source system is encrypted, the key used thereby is separately encrypted, and both the encrypted data and encrypted key are transmitted to and maintained by a data repository system. The repository system receives only the encrypted data and key, while the source system retains the ability to recover the key and in turn, the data. The source system is therefore assured of privacy and integrity of the archived data by retaining access control yet is relieved of the physical management of the warehousing medium.

Abstract: High performance backup of a computer system includes backing up changed portions of files and selectively choosing files for backup. Files are treated as a collection of blocks, and only those blocks which have changed since a previous backup are transmitted to a backup system. Prior to selecting blocks for backup, files are selectively chosen by excluding previously archived files such as commercial software, and excluding other non-critical applications and data based on, inter alia, commonality, modification date and a list of files which are already present in the backup system. Files may also be pre-loaded into a backup system in anticipation of their presence in the computer system to be backed up.