The purpose of strncpy, which was originally part of the UNIX kernel code, was to copy file names to and from directory entries that consisted of a 2 byte inode number and a 14 byte zero-padded but not zero-terminated name field.

I started warning my colleagues against using it the moment I saw it for the first time about 50 years ago.

strncpy appears somewhere around the Unix v7 time frame, however only as function in the standard C library. It is not used in the v7 kernel itself.