There are serveral differences in specific technologies used but they are all related in the resulting functionality. PIM (Privileged Identity Manager) was the original access control program which was replaced with a combination of PAM( Privileged Access Manager) and PAM SC ( Privileged Access Manager Server Control) programs. Later PAM and PAM SC were combined into PAM starting in PAM 4.0. Broadcom still supports both PAM SC and PAM separately and together but you should be aware that PIM is End of Service this September ( EOS Dates ). You should consider upgrading before too long.