This MIB is an extension of the ENTITY-MIB
specified in RFC2737.

This MIB module contains  Cisco-defined  extensions 
to the  entityPhysicalTable to represent information
related to entities of class module(entPhysicalClass
= 'module') which have a Processor.

A processor module is defined as a physical entity
that has a CPU, RAM and NVRAM  so that
it can independently
   - load a bootable image
   - save configuration.
This module is the entry point for external
applications like SNMP Manager, CLI, FTP etc.

Line card is an interface card         with at least a 
Processor and RAM. This might be referred to as 
Service Module in some cisco products.

A configuration register is  a 16 bit 
software register.
The configuration register is mainly used to 
check for instructions on where to find the Cisco 
Operating System software.
Some other functions of configuration register are:
 - To select a boot source and default boot filename.
 - To enable or disable the Break function.
 - To control broadcast addresses.
 - To set the console terminal baud rate.
 - To load operating software from Flash memory.
 - To allow us to manually boot the system using the 
   boot command at the bootstrap program prompt.

Booting is the process of initializing the
hardware and starting the Operating System.