VMS Help SORT, Output File Qualifiers, /ALLOCATION  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Specifies the number of blocks to be preallocated for the output
    file. Used for optimization when you know that the output file
    allocation will differ substantially from the total input
    file allocation (because you are reformatting data or omitting
    records).

    Format

      output-file-spec/ALLOCATION=n

1 - Qualifier Value

 n

    Specifies the number of blocks to be allocated. A value of 1 to
    4,294,967,295 is allowed.

2 - Full Description

    Sort/Merge preallocates space for the output file based on total
    input file allocation, thereby avoiding the overhead of extending
    the file every time another few blocks are written to it.

    However, if you know that the output file allocation will differ
    substantially from the total input file allocation (because you
    are reformatting data or omitting records), you can specify the
    number of blocks to be preallocated for the output file.

    The /ALLOCATION qualifier is required if the /CONTIGUOUS
    qualifier is used.

3 - Example

  $ SORT/KEY=(POS:1,SIZ:80) STATS.DAT -
  _$ SUMMARY.LIS/ALLOCATION=1000/CONTIGUOUS

      This SORT command allocates 1000 contiguous blocks for the
      output file SUMMARY.LIS.