Early computers of the 20th century famously required entire rooms. These days, you can carry much more processing power right in your pants pocket. Handheld computers like smartphones and PDAs are one of our era's iconic devices [source: Arthur].
Debuting in the 1990s, personal digital assistants (PDAs) were tightly integrated computers that often used flash memory instead of a hard drive for storage. These computers usually didn't have keyboards but relied on touchscreen technology for user input. PDAs were typically smaller than a paperback novel, very lightweight with a reasonable battery life. For a time, they were the go-to devices for calendars, email, and simple messaging functions [source: Britannica]. Remember the Palm Pilot and the BlackBerry?
But as the smartphone revolution began, PDAs lost their luster. Smartphones like the iPhone and Samsung Galaxy blend calling features and PDA functionality along with full-blown computer capabilities that get more jaw-dropping by the day. They feature touch-screen interfaces, high-speed processors, many gigabytes of memory, complete connectivity options (including Bluetooth, Wi-Fi, and more), dual-lens cameras, high-quality audio systems, and other features that would startle electronics engineers from half a century ago. Although smartphones have existed in some fashion since 2000, it was the heavily hyped debut of the iPhone 3G in 2007 that brought the device to the masses. The look, feel and functionality of that iPhone set the template for all the other smartphones that have followed [source: Nguyen].