VSI COBOL programs execute in a virtual memory environment.  Therefore,
  programs need not manage physical memory by overlaying Procedure
  Division code.

  In VSI COBOL, segmentation controls the assignment of Procedure
  Division sections to fixed or independent segments.  The optional
  segment-number in the section header specifies the type of segment.

  Format -

   section-name SECTION [ segment-number ] .

1  –  section-name

  names a Procedure Division section.

2  –  segment-number

  must be an integer in the range 0 through 99.  If there is no
  segment-number in a section header, the implied segment-number is 0.

3  –  fixed_segments

  Fixed segments appear to reside in memory at all times.  A fixed
  segment is in its initial state the first time the program calls it.
  On later calls, the fixed segment is in its last-used state.

4  –  independent_segments

  The state of an independent segment depends on how and when it
  receives control.