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| About Deleting Data |
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| Do you think that emptying the Recycle Bin will permanently
delete files? |
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| Do you think that formatting hard disk will permanently
erase hard drives' data? |
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| Actually, neither erasing files by
emptying the Recycle Bin nor formatting hard drives will
destruct data permanently. |
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Why aren’t they erased? |
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For example, to erase a file on Windows by emptying Recycle Bin means just to put information of "ERASED" in the index area. Data itself remains in the data area without being erased. Unfortunately, the file can be easily recovered and viewed by data recovery software within a few minutes. |
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Please try
this data recovery software, DataUndeleter to see if erased files on Windows can
be recovered. |
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How
to erase data permanently |
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To
erase a file permanently, you need to
overwrite data (for example, 0x00, 0xff,
random value, etc) in its index and data
areas. Normally, even if you simply overwrite
zero (0x00) on a file once, the data
cannot be recovered by any data recovery
software. But unfortunately the data
overwritten once or twice can be recovered
by magnetization pattern analyzers such
as Magnetic Force Microscopy (MFM). In
general, to erase data completely, it
is recommended to overwrite data at least
three times. |
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BluestSoft DiskDeleter supports DOD5220.22-M, which is the guideline published by the US Department of Defense for erasing magnetic media to guarantee that all data previously contained on that magnetic media is deleted permanently. |
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DOD 5220.22-M overwrites data total three times, first by 0x00 once then its compliment value 0xff once, and finally random values once. After the final process is complete, the disk is read to verify data to make sure there is no lingering pattern. |
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