| 摘要 |
A system, method and computer program product for hardware assisted backup for a computer mass storage subsystem wherein files to be backed up from a source storage medium (e.g. disk) to a formatted storage medium (e.g. tape) are written in logical block number ("LBN") order regardless of the file's on-disk layout. If the source file structure information is available it is used or the disk blocks containing the file structure are marked in a used (or "free") block bit map which may then be modified to exclude files that are "open for write", marked as "no backup" or not part of the selected file save operation. In operation, the blocks are written to tape using a Tape Copy Data ("TCD") command. Blocks that were selected, but excluded as "open for write" may then be written to the tape utilizing more conventional methodologies. Where possible, the entire disk volume is locked during the backup operation, however, individual files may be selectively locked if all of the files are not being saved. In those instances where the size of any group of contiguous data blocks is too small to be efficaciously backed up, unmarked blocks may also be included in the transfer to speed operation.
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