Understanding the Functionality of Tablets

In 2010, Steve Jobs put an end to years of speculation by unveiling the iPad, marking the beginning of a new chapter in computing. While tablet PCs existed prior to this, the iPad was the first to effectively capture the consumer market. Apple's success also paved the way for other companies as technology enthusiasts sought alternatives to Apple's model.

So, what exactly qualifies as a tablet? In its simplest form, a tablet PC is a mobile device larger than a smartphone or PDA. There isn't a fixed size for tablet devices, but the iPad has a screen just under 10 inches, with other tablets varying in size. Generally speaking, any device with a touchscreen interface and no built-in phone is considered a tablet.

To complicate things further, some manufacturers create hybrid devices that combine features of both tablets and laptops. These devices may include an attached keyboard, and the screen can swivel or fold to cover the keyboard, essentially transforming it into a tablet!

In 2010, Lenovo unveiled the IdeaPad U1 prototype at the Consumer Electronics Show in Las Vegas. At first glance, it appeared to be a standard laptop. However, by detaching the screen from the base, the laptop transformed into a fully functional tablet with its own independent operating system. Lenovo later rebranded this device as the Lenovo LePad, launching it in China in 2011.

Tablets come in various shapes, sizes, and feature sets, but they share many key similarities. Almost all of them feature a touch-screen interface and an operating system capable of running small applications. While they don't necessarily replace more powerful computers, they carve out a new space in the world of computing devices.

Let's explore the essential components that are common to most tablets.

What Drives Tablets Forward

If you were to open up a tablet to inspect its inner workings, you'd quickly observe three things. First, you'd have voided your warranty. Second, the manufacturer has carefully packed all of the tablet's components to ensure a compact and efficient design. And third, most of the parts inside are similar to those you'd find in a traditional computer.

The heart of a tablet is its microprocessor. Typically, tablets use smaller processors than standard computers, which helps conserve space and reduces heat production. Since excessive heat can lead to mechanical failures, keeping it low is crucial for the device's longevity.

Tablets usually rely on rechargeable batteries for power. Battery life can vary from model to model, with most tablets offering between eight to 10 hours of usage. Some tablets feature replaceable batteries, while others, like Apple's iPad and iPad 2, don't allow battery replacements without a visit to a store or voiding the warranty.

Depending on the manufacturer, a tablet may intentionally feature a less powerful processor. Computer CPUs operate in clock cycles—more cycles mean more instructions per second. Some tablets use underclocked processors, meaning they run fewer instructions per second than the CPU is capable of. This is done to minimize heat production and extend battery life.

Although it may be frustrating to realize your tablet isn't running at full speed, most tablets don't require the additional processing power. Tablet apps are typically simpler and less resource-intensive than those for computers, so the device doesn't need to push its processor to the limit.

In addition to the CPU and battery, a typical tablet also contains a variety of other essential components, such as:

Accelerometers and gyroscopes are key in helping the tablet recognize its orientation, enabling the screen to switch between portrait and landscape modes. The graphics processor (GPU) offloads the CPU, improving graphics rendering. The WiFi or cellular hardware ensures network connectivity, while a Bluetooth receiver lets the device communicate with other Bluetooth-enabled gadgets. Most tablets don't feature a fan, simply due to space constraints.

Touch Screens and Tablets

Tablets feature two primary types of touch screen technology: resistive screens and capacitive screens. Manufacturers must choose between the two, as they cannot be used together.

Resistive screens detect touch through pressure. Tablets that require a stylus typically use resistive screens. But how does this process work?

Resistive screens consist of a layer of resistive material and a conductive layer. These layers are separated by spacers. When the tablet is powered on, an electric current flows through both layers. Pressing the screen brings the two layers into contact, altering the electrical field between them.

Imagine you're using a tablet and want to open a game. You tap the game icon on the screen with your stylus. The pressure you apply causes the two layers in the resistive system to touch, disrupting the electric field. A microchip inside the tablet detects this change and converts it into screen coordinates. The CPU then matches these coordinates to the operating system, launching the app.

Resistive screens can be prone to damage. Excessive pressure can cause the two layers to remain in constant contact, leading to misinterpreted commands. Additionally, resistive screens often offer lower resolution compared to capacitive screens.

A capacitive system detects changes in electrical fields but doesn't require pressure. This system includes a layer of material that holds an electrical charge. When you touch the screen with a conductive object, some of the charge transfers to the object. However, only conductive materials will be recognized by the system. Unlike resistive screens, which can register touch from anything, capacitive screens only register input from conductive materials.

Capacitive systems are generally more durable than resistive ones, as they don't require a firm press to register a touch. They also tend to offer a higher resolution compared to resistive systems.

History of Tablets

The concept of the tablet computer dates back to 1968, when computer scientist Alan Kay envisioned a device that combined advances in flat-panel displays, user interfaces, miniaturization of components, and experimental WiFi technology. He believed that these innovations could lead to a versatile all-in-one computing device. Further developing the idea, he suggested that such a device would be ideal for educational purposes, especially for schoolchildren. In 1972, he published a paper outlining this vision, naming the device the Dynabook.

The sketches of the Dynabook reveal a design strikingly similar to modern tablets, with a few key differences. The Dynabook featured both a screen and a keyboard on the same surface. However, Kay's vision was even more forward-thinking. He predicted that with the right touch-screen technology, physical keyboards could be eliminated, and a virtual keyboard could appear on the screen in any desired configuration.

Alan Kay was ahead of his time. It wouldn't be until nearly forty years later that a tablet similar to the one he imagined would captivate the public. However, that doesn't mean tablets didn't exist between the Dynabook concept and the release of Apple's revolutionary iPad.

One of the early tablets was the GRiDPad, which debuted in 1989. It featured a monochrome capacitive touch screen and came with a wired stylus. Weighing just under 5 pounds (2.26 kilograms), the GRiDPad was considerably bulkier than today's tablets and had a relatively short battery life of only three hours. Jeff Hawkins, the inventor behind the GRiDPad, would later go on to found Palm.

Other pen-based tablet devices followed, but they never gained much traction with the public. Apple's entry into the tablet market came with the Newton, a device that has been both praised and ridiculed over the years. Much of the criticism of the Newton centers on its handwriting recognition software.

It wasn't until Steve Jobs introduced the first iPad to an enthusiastic audience that tablet computers truly became a feasible consumer product. Nowadays, companies such as Apple, Google, Microsoft, and HP are racing to anticipate consumer demands while crafting the next wave of tablet devices. Although it took some time for tablets to gain momentum, it seems clear that they will continue to populate store shelves for many years ahead.