| # Section 8.10.1.3: $INOUT_DEVICE |

###### abstract class $INOUT_DEVICE < $IN_DEVICE, $OUT_DEVICE

#### Formal Definitions

This abstract class defines a state component which is a set of all instantiations of objects of any class sub-typing from this class in addition to the vdm model types used wherever this class name is used. Note that SAME has to be an instantiated class, not an abstract one.

types
SAME = object_type ;
$INOUT_DEVICE = set of object_type
state
multi : $INOUT_DEVICE
inv multi_types ==
forall obj in set multi_types & sub_type($INOUT_DEVICE,obj)

NOTE | See the important note about vdm state in the notes on vdm-sl usage in this specification.

This abstraction models a generic input/output device which may be of any kind which is, at least potentially, capable of importing and exporting data. It defines no features of its own.

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Comments or enquiries should be made to Keith Hopper. Page last modified: Friday, 14 July 2000. |