HANDS ON GUIDE

8 - Cloud Computing

Everywhere you go, you can always take the weather with you

WHAT IS IT?

Cloud computing is a software model where your applications and their data don't need to reside on the same computer. You can use a client on any machine with an internet connection to access a server to load the program and its data; the server then relies on a database on another computer (which could be located in a different continent). One component may be upgraded, changed or replaced without affecting the other parts.

An MMORPG is a good example. A server may receive a patch that alters the game, although the client doesn’t need to download anything. Web-based email applications such as Hotmail are another. Your mailbox and information resides on a server somewhere, but any device connected to the web can retrieve the information. Spore makes use of a cloud computing model, by distributing your creations to a central server, where other players can use them in their games. Google Docs is another - an entire word processor is stored on a remote server, the client is displayed in your web browser and the document is stored online. Adobe and Flickr now offer similar tools for image editing, and simple spreadsheets, databases and calendars can all be created in this way.

Both Microsoft and Google are heavily promoting the idea of cloud computing. Google's recently released Chrome browser allows you to create links to web applications and runs each tab as a separate process in order to allow for more complex software to be run over the web. As developers prove it's possible for more and more software to be run over the web, it's inevitable someone will try and develop an entire OS as a cloud app. This would mean PCs reverting to the dumb terminals (similar to those used in the 70s, powered by mainframes). While having your OS stream in from a server could potentially make patching seamless, and make for effective backup, security and performance would be a concern.

HOW DOES IT WORK?

At its basic level, a cloud computing application is simply a piece of software that you access via a web browser and which uses hosted storage, rather than local. Client and server software modules sit on each end to pass messages between your app (the browser, or a piece of client software) and the app on the server (Gmail, World of Warcraft). One problem with the design of such systems is processing messages in the right order. Ensuring that data is only modified by a single client, and that every part of a transaction is completed before processing another is of huge importance. Some exploits in online games have made use of flaws in database updates such as this.

WHAT COULD GET IN THE WAY?

Speed and cost, the two reasons the mainframe and dumb terminal model was abandoned by home users in the 1980s. Home computers such as the Apple II, IBM PC and TRS-80 were cheaper to buy and maintain and, because CPUs, memory and storage evolved faster than network data transmission, were also quicker at running applications. Running an application over the web requires a fast data link and requires the company hosting the app to invest huge amounts of money in backend processing power. Google and Microsoft are spending billions on data centres - both have recently announced they will be spending half a billion dollars each on data centres in one US state alone.

1 | 2

Latest Hands on guides

These are the most popular features articles over the past three months.

Mobile Broadband

Compare prices

Fastest, cheapest 3G mobile broadband dongles from 3, Vodafone, T-Mobile and Orange
from just £10/month