A tablet computer is a portable computer whose main method of interaction is via a touch screen.
Tablets had been around for years without creating too much excitement, but the release of the iPad in April 2010 started the current wave of interest in tablet technology.
The impact of the iPad led a number of other computer manufacturers to swiftly release similar devices using Windows, Android or Linux operating systems. Most of these proved to be poor competitors to the iPad, but recently a number of Android alternatives have also become very popular. Examples include the Galaxy Tab, the Nexus 7 and Nexus 10, and the Kindle Fire.
While the iPad has a 9.7 inch screen, measured diagonally, and the iPad mini's screen is 7.9 inches across, most other tablets have either 7 inch or 10 inch screens.
Some of the good points about tablets include:
Some - like the iPad - have very limited physical connections, assuming all sharing and printing will be done over the Wi-Fi connection. Others like the Samsung Galaxy Tab have USB ports for connecting printers and external drives. Many include SD slots to allow easy copying from camera memory cards.
The iPhone and iPod touch look very similar to each other, and the iPad looks like a large version of the other two. They all run the same operating system and run mostly the same apps, so what exactly are the differences?
Well, the iPhone is the only one of the three which can be used as a phone. It also comes with both Wi-Fi and 3G connectivity, while the iPad is available as a Wi-Fi only version and a Wi-Fi and 4G version. The iPod touch has only Wi-Fi.
The iPhone is also the only one which has a built-in GPS receiver, although it is possible to buy an external GPS receiver for all three. A GPS receiver is needed for satellite navigation.
Other differences include:
One interesting development within this space is the take-up of the iPhone or iPod touch by blind people. These aren't considered tablets in the mainstream because of the small screen, but the operating software and screen reader are the same in these as in the iPad, and if you're not bothered about the screen, then they make very good - and very portable - replacements. With the addition of a small Bluetooth keyboard - or even, if you have the money and read braille, a 12-cell braille display with input keys - you've got a machine that you can do all your email and web work on and it all fits in your handbag or pocket!
For low vision users of any of these devices who require the built-in magnification, using the on-screen keyboard is problematic. It is possible to use a Bluetooth keyboard with it, and an iPad dock is also available.