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Portable Network Graphic  |  1996-09-11  |  150KB  |  816x1056  |  8-bit (256 colors)
OCR: than 20% of the volume is in use or when you have verifiably reliable backups of the volume Copy changed blocks only This option was new in version 2.0 When selected, CopyThru creates and updates special file, "CopyThruCRC" on the destination volume This file con tains a 32-bit checksum for each used allocation block on the volume. If at later date you copy the same (or slightly modified) source volume to the destination volume all used source blocks are read and their chec ksums computed If the checksum of 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 do periodic backups of volume the volume doesn' drastically change 5% of the b ...