MPE/iX Shell and Utilities Reference Manual, Vol 2

MPE/iX does not allow multiple hard links to files or directories. Each file has a maximum link count of
1. A file is considered removed if its link count is zero. Note, however, that processes that are accessing
a file when its link count becomes zero can continue to access the file; upon closing the file, the process
cannot again open the file.
MPE/iX Implementation Considerations A-9