Complex sentence: The ADSTAR name is today primarily associated with a backup and recovery product originally named ADSTAR Distributed Storage Manager (ADSM) but ater Tivoli Systems was purchased by IBM, it was renamed Tivoli Storage Manager (TSM).
Split into simpler sentences: The ADSTAR name is primarily associated with a backup and recovery product originally named ADSTAR Distributed Storage Manager (ADSM). After Tivoli Systems was purchased by IBM, ADSM was renamed Tivoli Storage Manager (TSM).