Xerox® Security Guide for Light Production Mono Class Products
Marking Engine
The Marking Engine performs copy/print paper feeding and transport, image marking, fusing, and
document finishing. The marking engine is comprised of paper supply trays and feeders, paper transport,
LED scanner, xerographic, and paper output and finishing. The marking engine is only accessible to the
Controller via inter-chip communication with no other access and does not store user data
.
Name
Purpose/Explanation
Flash ROM
All operating system and application executable control code related to Marking
Engine resides here (e.g. boot loader, paper path, and xerographic).
SRAM
(Static RAM)
This is a Work RAM used to develop the program and parameters in the
above-mentioned Flash ROM. No user data is stored in this memory.
Controller
The controller manages document processing using proprietary hardware and algorithms to process
documents into high-quality electronic and/or printed reproductions. Documents may be temporarily
buffered in RAM during processing. Some models may be equipped with additional storage options such
as magnetic Hard Disk Drive (HDD), Solid State Disk (SSD), SD Card, or Flash media. For model
specific details please see
Appendix A: Product Security Profiles
. Legacy and D-Series® products
encrypt user data and include media sanitization (overwrite) options that ensure that erased data cannot
be recovered, described further in section
In addition to managing document processing the controller manages all network functions and services.
Details can be found in section
The controller handles all I/O communications with connected products. The following section provides a
description of each interface. Please note that not all interfaces are supported on all models; details
about each model can be found in
Appendix A: Product Security Profiles
The details of the memory devices in the Controller are:
Name
Purpose/Explanation
DRAM
The executable software is loaded in this memory and is run. This memory is
also used for temporary storage of user data such as data files and images.
Such data is not backed up and is deleted when a job is completed. And the all
data is lost when the power to the device is removed.
Flash ROM
This Flash memory contains the code necessary to boot the system, all
executable code (operating system, PostScript interpreter, network protocols,
document scheduler, etc.), and the installed fonts. A power-on self-test is
performed and the bootstrap OS is loaded. This memory never contains any
user data or document data.
Operating system and application executable control code resides here. All
codes except for the code of boot loader are compressed and are extracted
into DRAM to be executed. No user image data is stored in this memory.
NVRAM
This non-volatile memory has no image data stored in it. User data such as
system setting information, mailbox information, job memory, user
management information, and various types of logs are recorded in it. The data
is written in the memory after it is encrypted.
