A data storage library is described that essentially provides a write once and read many (WORM) conversion station located inside of the data storage library. After receiving a request to store data in a WORM arrangement on a tape cartridge in the data storage library and appropriate tape cartridge is selected from a scratch pool of tape cartridges, brought by a robotic transporter to a WORM station where the tape cartridge is converted into a WORM tape cartridge. The WORM tape cartridge can be converted back to a non-write disabled tape cartridge at the WORM station.