/sys$common/syshlp/helplib.hlb MERGE, /WORK_FILES, Qualifier Value  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 n

    Specifies the number of work files requested; 1 to 10 files may
    be specified. The default value is 2.

    High-performance Sort/Merge: The high-performance Sort/Merge
    utility allows you to specify from 1 to 255 work files. The
    default value is 1.