WorkCentre 7220-7225 Information Assurance Disclosure Paper
Ver. 1.0, January 2013
Page
49 of 61
4.7.
Image Overwrite
The Image Overwrite Security feature provides both Immediate Image Overwrite (IIO) and On-Demand Image
Overwrite (ODIO) functions. Immediately before a job is considered complete, IIO will overwrite any temporary files
associated with print, network scan, internet fax, network fax, or e-mail jobs that had been created on the controller
Hard Disk. The ODIO feature can be executed at any time by the SA and will overwrite the entire document image
partitions of the controller Hard disk. Scheduled ODIO may also be configured to run at specific times.
A standard ODIO will overwrite all image data from memory and disks except for Jobs and Folders stored in the
Reprint Saved Jobs feature; Jobs stored in the Scan to Mailbox feature (if installed); Fax Dial Directories (if fax card is
installed); and Fax Mailbox contents (if fax card is installed). A full ODIO will overwrite all image data from memory
and disks as well as the items excluded from a standard ODIO.
4.7.1.
Algorithm
The overwrite mechanism for both IIO and ODIO conforms to the U.S. Department of Defense Directive 5220.22-M
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
disks (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
disks (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
disks (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.
4.7.2.
User Behavior
Once enabled at either the Local UI or Web UI, IIO is invoked automatically immediately prior to the completion of a
print, network scan, embedded fax, internet fax, network fax, or e-mail job. If IIO completes successfully, status is
displayed in the Job Queue. However, if IIO fails, a popup will appear on the Local UI recommending that the user
run ODIO, and a failure sheet will be printed.
ODIO may be invoked either from the Local UI in Tools Pathway or from the CentreWare Internet Services Web UI.
Network functions will be delayed until the overwrite is completed. Copying is unavailable while the overwrite itself is
underway, but copies may be made while the controller is booting.
Upon completion of the ODIO process, a confirmation sheet which can be turned On or Off by the Administrator is
printed in the event of failure. Should this occur, it is recommended that it be re-run.
Please note that invocation of ODIO will cause currently processing print jobs to be aborted. However, scan jobs will
not be aborted and so ODIO might fail. The user should insure that all scan jobs have been completed before
invoking ODIO. Please refer to the customer documentation for a description on how failures are logged.
