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Portable Network Graphic  |  1997-04-17  |  153KB  |  816x1056  |  8-bit (256 colors)
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OCR: Copy changed blocks only When selected, CopyThru creates and updates a special file, "CopyThruCRC" on the destination volume. This file contains 32 -bit checksum for each used allocation block on the volume. If later date you copy the same (or slightly modified) source volume to the destination volume all used source blocks are read and their checksums computed. If the checksum of 1 source block differs from the previously stored checksum then CopyThru knows that the block has changed and writes the block to the destination volume otherwise the block is not written If you use CopyThru to op periodic backups JO volume the volume doesn't drastically change e 5% of the blocks are changed with each backup) and ma disk insertions are typ ically needed, then you can avoid many insertions by usin ...