CD

CD (Compact Disc) was a digital-based storage disc used on Earth in the late 20th century and early 21st century. Regular CDs were usually used to store recorded music, while CD-ROMs were used to store computer data.

In 1998, the CD-ROM containing VORACIA was stolen by Kevin Sutcliffe, who passed it on to the Doctor before he was killed. (MA: System Shock)

In 1999, the Jex plans for invading Earth were recorded on a CD-ROM which was acquired by the CIA. (PDA: The King of Terror)

In 2002, Ace acquired a CD-Walkman from Paul Tanner, which she took with her to 1944. There, it was acquired by Nazi scientists, who developed laser technology from studying it, enabling Germany to win World War II. (BFA: Colditz)