What do Metallica and SanDisk have in common? For both, the memory remains. The metal band was singing about faded rock stars trapped in their glory days. The data storage company, however, is hoping that music-filled 1GB microSD memory cards will lure in consumers who fondly remember when their favorite songs were purchased on albums preloaded on physical media and weren’t downloaded via the Internet. SlotMusic, SanDisk’s new initiative, offers an entire album of digital rights management-free music on a memory card.