All you need to know about apps

These days it seems that apps are everywhere. Newspapers ask us to download their own app, television adverts claim that one phone has more apps than another, and, of course, Apple posters proclaim that, whatever you need, “there’s an app for that”. But just what is an app, anyway?

At its simplest level, the word app – short for application – is a trendy new term for something we have all used and understood for years: a computer program.

Just as the Microsoft Excel program allows you to create spreadsheets on a computer, so the Numbers for iPad app allows you to do the same on an iPad. But there is a little bit more to the concept of an app: in particular where apps run and how they are installed.

Where does an app run?
One key difference between a program and an app is where it runs. It’s common practice to use the word 'program' when talking about something that runs on a desktop or laptop computer, whether it runs Windows, Linux or Apple’s Mac OS operating system, while the term app is used to refer to software that runs on some other kind of device.

The most common place to find apps is on a smartphone – and in fact ‘a mobile phone that can run some apps’ has become a decent definition of what makes a smartphone smart.

There are thousands of apps available for the Apple iPhone, for example, and phones that run the rival Android, Symbian and Windows Mobile operating systems. And they’re cropping up on larger tablet devices such as the Apple iPad and Samsung Galaxy Tab.

Simpler installation
The other key difference between a program and an app is how you get and install it. We're all familiar with the process of installing programs on a computer, so we sometimes forget that it's not very simple: we buy the software, either from the manufacturer or another seller, get it on disc or as a download, then run a special tool that, often after dozens of mouse clicks, installs it onto your computer.

With an app the process is different, and usually far simpler. Whatever kind of device you’re using, apps are not purchased from the maker, or from a shop, but from a single, central marketplace designed for that device. The best known is Apple’s unimaginatively named App Store for its iPhone and iPad devices.

This makes the process of finding and choosing apps simpler than that of choosing normal software. There is no need to find the ones that will run on your PC, for example, as app marketplaces will only offer you apps that are guaranteed to run on your device.

Putting apps in your laptop
So far, so simple: we have shown that apps run mostly on phones and other non-computer devices, and that you buy them from a special dedicated store. In the near future, though, it appears that one of these could change.

Since companies have had such great success selling apps to users of mobile phones and other devices, many want to get in on the act in order to sell to laptop and desktop computer users.

In particular Intel, which makes the processor chips used in many laptop and desktop computers but no common smartphones, has created a store called App Up, which is in turn used as the basis of PC World’s own app store for netbooks.

And it’s not just a case of other companies attempting to jump on a bandwagon led by Apple: Apple itself has announced that the next version of its operating system for Mac personal computers, OS X Lion, will also include an app store that works in much the same way as the one on the company’s mobile devices.

Program problems
So far we have focused on the benefits of apps: they are simple and easy to buy. But there are some downsides to the whole system that are worth noting.

The first is cost: when it comes to a normal PC application, you are normally able to shop around to get the best deal. But on the iPhone, for example, that’s not possible: the only place to buy any given app is from the Apple App Store, and that has a set price.

Second, there is the more philosophical matter of who gets to control what goes on your computer, phone or device. When it comes to normal software, you get to choose: if you can find a program that will run on your computer, you can go ahead and run it.

With an App store, however, there is a degree of control: whoever manages the store can choose what goes in it. This has some advantages, allowing companies to filter out dangerous software, but means users are effectively offered only a censored list of tools.

Apple maintains a tight grip on its App store, with guidelines that state: “We will reject Apps for any content or behaviour that we believe is over the line. What line, you ask? Well, as a Supreme Court Justice once said, ‘I'll know it when I see it’.”

And it doesn’t stop there. As well as controlling what software goes onto your computer, app stores can sometimes take it off, even without your consent.

Both Apple and Google have confirmed that their App stores have a so-called ‘kill switch’ that allows them to remotely remove software from customers’ phones.

This kind of behaviour would be especially troubling if a single app store were the only way to get programs onto your computer but for the moment this isn’t the case, and for many people the simplicity that apps offer compared to installing other software on mobile phones makes them a really handy option.

Apps around the house
Although apps are most commonly found on mobile phones, manufacturers of other devices have been quick to add them to their products.

Lexmark, for example, makes a printer that can use apps to print images directly from the internet, while Samsung is among the companies who have put apps into their latest internet-connected televisions.

Samsung's Internet@TV system includes apps to show social networking websites and stream movies.

For more about the kinds of devices that can make use of apps, keep an eye on Computeractive's Reviews section.