The PTYPE Field

Most parameters are associated with values of one type or another, e.g. primitive data types, or data-system objects. These are known as normal parameters.

However, there is a class of parameters which are intimately associated with some type of device (e.g. a magnetic tape drive, or a graphics terminal). These are known as device parameters. Device parameters are typically used in calls such as GKS_ASSOC. A parameter is defined as a device parameter by the PTYPE field.

PTYPE  parameter-type

where parameter-type is a character string which can currently only be DEVICE.

The precise type of the device can be indicated by the TYPE field. The specification for parameter DISPLAY in our example above would then be:

PARAMETER DISPLAY
      .
   PTYPE DEVICE
   TYPE GRAPHICS
      .
ENDPARAMETER

The value of a device parameter is a name which can be translated to define the device to be used. For details of possible values, see the appropriate facility description, SGS, GKS, FIO etc.

Currently PTYPE is not used by the system - only the TYPE is of significance and there anything other than a standard HDS type will have the same effect.