/sys$common/syshlp/helplib.hlb SEARCH, Qualifiers, /KEY  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /KEY=(POSITION=n,SIZE=m)

    Searches the records of a file (beginning at the specified
    position) for the length of the specified size.

    You can specify the POSITION keyword value as 1 to 32,767. The
    first byte in a record is considered position 1.