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.

iPad... and beyond!

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.

Good points

Some of the good points about tablets include:

  • Start-up speed - tablets have a "sleep" mode, and people often use this rather than turning them on and off. It takes only a second or two to enter or leave sleep mode, which means you can pick your tablet up and be using it very quickly.
  • Long battery life - at least four to five hours, with many nearer to eight or ten hours.
  • Simplicity of screen and controls - because you use touch rather than a keyboard or mouse to work a tablet, everything has to be quite large, and there isn't room for much on the screen. Once you've mastered a few "gestures" like tapping or swiping, you're away!
  • Low weight - tablets are portable, so they are light and thin and can happily fit in a handbag, day sack or even a large pocket.
  • Built-in Wi-Fi - tablets make use of the Internet for lots of things, so they have to be able to connect easily. With Wi-Fi built in, you can use your tablet in coffee-shops and pubs, on buses and trains, at home or work - anywhere you're likely to be.

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.

Comparison of iDevices

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:

  • Screen size on the iPad is 25cm. The iPad mini's screen is 20cm, the iPhone 5 and the iPod touch screens are 10cm, and the iPhone 4S has a 9cm screen. The overall size and weight of the units is consequently different.
  • The iPad, iPhone 5 and iPod touch have 16GB, 32GB and 64GB storage options. The iPad also has a 128GB option, and the iPhone 4S is only available with 8GB.
  • Battery life is notoriously difficult to be exact about, because it can vary so much depending on what you do. Apple say that the iPad gives you 10 hours of watching video or listening to music; the iPhone gives 10 hours of video playback, 40 of audio playback or 8 hours of talk time on 3G; the iPhone 5 has the same audio and video playback but up 10 hours of talktime the iPod touch gives you up to 8 hours of video playback or 40 hours of music playback.
  • The iPad costs from £329, the iPad mini from £249 and the iPod touch from £199. The iPhone 4S starts at £349 and the iPhone 5 from £469, although it's more usual to get the iPhone on contract from a number of companies. If you get the 4G iPad, you will also need a contract to use the 4G.
  • The apps that come with the units vary slightly. Only the iPhone is a phone and has a compass. The iPad doesn't have calculator, passbook, stocks, voice memos or weather.

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.