ABSTRACT
Since the 1990s, mobile computing has transformed its penetration from niche markets and early prototypes to ubiquity. Personal digital assistants (PDAs) evolved from GRiD’s PalmPad and Apple’s Newton in 1993 to the Palm, Handspring, and Microsoft-based models that support the multibillion dollar industry today. Although BellSouth/IBM’s Simon may have been the only mobile phone to offer e-mail connectivity in 1994, almost every modern mobile phone provides data services today. Compact digital music players have replaced cassette and CD-based systems, and these “MP3 players” are evolving into portable repositories for music videos, movies, photos, and personal information such as e-mail. Laptops, which were massive and inconvenient briefcase devices in the late 1980s, now outsell desktops in some markets. Yet, all these devices still have a common, difficult problem to overcome: power.
