Disk Image Overwrite
Overview
The Disk Image Overwrite feature has two operations: Immediate and On Demand. The immediate operation overwrites image data on the hard drive immediately after it is no longer needed (i.e. When the page has printed). The On Demand operation cleans the entire disk. Both On Demand Image Overwrite and Immediate Image overwrite feature are configured by the system administrator, assuming that the system administrator password is set to a
Algorithm
The overwrite algorithm for both IIO and ODIO conforms to the U.S. Department of Defense Directive
The algorithm for the Image Overwrite feature is:
Step 1: Pattern #1 is written to the sectors containing temporary files (IIO) or to the entire spooling area of the disk (ODIO). (hex value 0x35 (ASCII “5”)).
Step 2: Pattern #2 is written to the sectors containing temporary files (IIO) or to the entire spooling area of the disk (ODIO). (hex value 0xCA (ASCII compliment of 5)).
Step 3: Pattern #3 is written to the sectors containing temporary files (IIO) or to the entire spooling area of the disk (ODIO). (hex value 0x97 (ASCII “ú”)).
Step 4: 10% of the overwritten area is sampled to ensure Pattern #3 was properly written. The 10% sampling is accomplished by sampling a random 10% of the overwritten area.
See Online Help in Web Printer Management Tool for more details about using the Image Overwrite feature.
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