18 lines
920 B
Text
18 lines
920 B
Text
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Wipe is a secure file wiping utility.
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There are some low level issues that must be taken into consideration.
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One of these is that there must be some sort of write barrier between
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passes. Wipe uses fdatasync(2) (or fsync(2)) as a write barrier, or
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if fsync(2) isn't available, the file is opened with the O_DSYNC or
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O_SYNC flag. For wipe to be effective, each pass must be completely
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written. To ensure this, the drive must support some form of a write
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barrier, write cache flush, or write cache disabling. SCSI supports
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ordered command tags, has a force media access bit for commands, and
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write cache can be disable on mode page 8. IDE/ATA drives support
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write cache flushes and write cache disabling.
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Unfortunately, not all drives actually disable write cache when asked
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to. Those drives are broken. Write caching should always be
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disabled, unless your system is battery backed and always powers down
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cleanly.
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