Paragraph Number

247

Typically, when data is no longer useful it may be erased. In many file systems, an erase command deletes a directory entry in the file system while leaving the data in place in the storage device containing the data. Typically, a data storage device is not involved in this type of erase operation. Another method of erasing data is to write zeros, ones, or some other null data character to the data storage device to actually replace the erased file. However, this is inefficient because valuable bandwidth is used to transmit the data for the overwrite operation. In addition, space in the storage device is taken up by the data used to overwrite invalid data.

Added by DJM 3 2021