Sequential access provides a way to sequentially read/write the values physically stored for a variable. To use sequential access, a starting value must first be selected by specifying a record number and dimension indices. This selects the ``current sequential value.'' A sequential read will return the value at the current sequential value and then automatically increment the current sequential value to the next value. Likewise, a sequential write will store a value at the current sequential value and then increment the current sequential value to the next value. Sequential reads are allowed until the end of the physical records has been reached (not the end of the virtual records [they never end]). Sequential reading will increment to the beginning of the next physical record if necessary. Sequential writing can be used to extend the physical records for a variable (as well as to overwrite existing values).