	System configuration overview
	------ ------------- --------

Purpose of new configuration support:
	
	* Provides a way to detect inoperative components of the
	  system which don't respond to software probing.

	* Allows a user to explicitly configure out broken components 
	  without having to physically remove them from the machine.

	* Assists FE's by allowing them to configure out components
	  during diagnostic process.


Implementation:

	The IO4 NVRAM contains a configuration structure of the
	following form:

	typedef struct {
		uchar	  cf_status;
		uchar	  cf_diagval;
	} config_t;

	typedef struct {
		uchar	  bcf_class;
		uchar	  bcf_type;
		uchar	  bcf_rev;
		config_t  bcf_status;
		config_t  bcf_unit[CFG_MAXUNITS];
	} brdconfig_t;


	The NVRAM contains a brdconfig structure for each of slots
	in the Everest backplane.  When a new device is recognized,
	the brdconfig structure for it is initialized based on its
	class (IO, MEM, CPU) and type (IO4, IP19, IP21, MC3).  
