VMS Help PASCAL, Attributes, Parameter, CLASS_A  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The CLASS_A attribute causes a formal parameter to be passed  by
  an  array  descriptor that describes contiguous arrays of atomic
  data types or contiguous arrays of fixed-length  strings.   This
  is  the  default  mechanism  for  conformant array parameters on
  OpenVMS VAX systems.  This attribute is illegal on parameters of
  schema types.

  See the  "Compaq  Pascal  Language  Reference  Manual"  for  the
  complete description of using the CLASS_A attribute.