Generic Hardware Resource Classification

Generic Hardware Resource Classification

      By defining a generalized taxonomy (resource class/subclass)
for describing various types of I/O hardware resources and
classifying specific devices within that taxonomy, it is possible to
differentiate between various classes of hardware without a
dependency upon type/model values of those devices.

      A resource class/subclass field allows I/O subsystem resources
to identify their function to a host system in a generic manner not
dependent upon specific type/model interpretation.  This field is
divided into two subfields--resource class and resource subclass.

      A resource class field allows an I/O subsystem component to
identify the general class of function it provides.  Examples of such
classes are DASD, tape, workstations, communications, or
special-purpose I/O.  As additional I/O classes are defined, it is
possible to assign additional code points.

      The definition of the resource subclass field is dependent upon
the value of the resource class field.  For each resource class, a
wide range of different resource subclasses may be defined.
Subclasses are clustered into various groups depending upon the value
of the high-order nibble of the resource subclass field.  For
example, within the DASD resource class, a subclass value of X'1x'
indicates non-removable magnetic media devices, X'2x' indicates
removable magnetic media, X'3x' indicates write- once optical media,
and X'4x' indicates multi...