The ‘cloud'

Much of our computing is now being done remotely via the ‘cloud'. However what is it? Here is a brief history of this radical shift during, below, we assess the relative merits of four cloud computing services

The computer go?

‘Where did the computer go?" was the slogan Apple used in 2004 when it launched the first of its current range of iMac desktop computers.

But as a matter of fact it's a question with a more contemporary relevance, because in these times most of us rely on "computing" that's provided by machines we never see and could not locate even if we tried.

The internet cloud

They are somewhere out there in the internet "cloud", which is how so many of us came to be users of something called "cloud computing".

And the data - the documents, calculations or messages - that you produced were in the same fashion stored on the hard drive inside your machine. Even if the PC was connected to the net, most of your computing activity happened inside the box on your desk.

And now? First, most of what we think of as "computing" is increasingly done using a smartphone or an iPad or a simple, stripped-down, laptop or "netbook". Much of our data - documents, emails, photographs, spreadsheets - is no longer stored on our devices nevertheless is held in distant server farms operated by the likes of Google, Yahoo, Facebook, Amazon and Microsoft.

And if you're a serious user of computing resources you will not only store your stuff in the cloud, however rent virtual computers from companies just as Amazon on which to run your own programs.

What made this possible

What made this possible was the penetration of broadband - ie internet connections that were fast enough to ensure that interactions with distant machines happened at a tolerable speed. Once these types of connections became widespread, the die was cast.

For individuals, reliance on cloud computing came about mainly because companies just as Microsoft, Google and Yahoo offered useful services - think search, webmail, image hosting and social networking - that were to all appearances free and required no special software running on their computers.

Building and running IT services for thousands of employees is an expensive and unrewarding business. However for several decades companies had little alternative - such as a century ago they had no alternative except to build and operate their own electricity generators.

But in the end it became possible to purchase electricity off the grid, in short most companies shut down their generators and left the messy business of producing electricity to utility companies.

The same with computing services

Now they're doing the same with computing services, which they regard as a utility - just like electricity or water. That is, the net has become another kind of grid.

iCloud launched in early October, promising a simple and elegant way to store music, photos, documents and other files on Apple's servers and at the time access them from iPhone, iPod touch, iPad and computers.

For example, a feature called Photo Stream makes all the photos you take appear on your other devices for up to 30 days.iCloud as well lets you download all your previous purchases on Apple's iTunes Store to your Apple-registered devices.

Meanwhile, developers making apps for Apple devices can as well use iCloud's storage. Early examples include game saves being accessible across iPhone and iPad, and document editing apps working across all these devices.

iCloud works on any iPhone, iPad or iPod touch running the iOS 5 software, as so then as any Mac running the OS X Lion operating system.

iCloud involves a lot of your personal content being sent over the internet and/or stored on Apple's servers, though the company uses encryption research to keep it secure. Apple as well has a policy of only storing location data from individual devices for 24 hours on its servers previously deleting it.

Microsoft's SkyDrive is part of its Windows Live service, with strong links to services just as Hotmail, Windows Messenger and Xbox Live. It's more of a virtual hard drive in the cloud, using a similar system of folders to organise your stored files.

Digital cameras and smartphones mean a lot of people have thousands of photos stored on their computers. Why store them in the cloud too? In some cases to make them easier to share, nevertheless also for security: a back-up in case your hard drive comes a cropper.Flickr is the best-known cloud photos service, though in recent years it has faced serious competition from Facebook.

Apple's iCloud will in the near future be the most high-profile cloud music service in the UK, however there are already rivals available.Sony's Music Unlimited is one of the best, because it combines the ability to store your existing music collection in the cloud with a Spotify-style library of songs you don't own, to stream.

It works on computers, nevertheless also Android devices and the PlayStation 3 console. Carphone Warehouse as well has a cloud music service, My Music Anywhere, which stores your collection online, including playlists, and allows you to access it from other computers and your smartphone.