On Alpha and Integrity server systems, writes all pages (or
    only those pages modified by the current process) in an active
    private or global disk file section back into the section file
    on disk. One or more I/O requests are queued to perform the write
    operation.
    The $UPDSEC_64 service completes asynchronously. For synchronous
    completion, use the Update Global Section File on Disk and Wait
    ($UPDSEC_64W) service.
    This service accepts 64-bit addresses.
    Format
      SYS$UPDSEC_64  start_va_64 ,length_64 ,acmode ,updflg ,efn
                     ,iosa_64 ,return_va_64 ,return_length_64
                     [,astadr_64 [,astprm_64]]
    C Prototype
      int sys$updsec_64  (void *start_va_64, unsigned __int64
                         length_64, unsigned int acmode, unsigned
                         int updflg, unsigned int efn, struct _iosa
                         *iosa_64, void *(*(return_va_64)), unsigned
                         __int64 *return_length_64,...);
Additional Information:
explode
extract