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Last Updated: Monday, 23 July 2007, 14:16 GMT 15:16 UK
Factfile: XO laptop
The One Laptop Per Child project is one step closer to releasing the completed machine to millions of schoolchildren in the developing world. But what makes the computer so unique?

Internal hardware Computer screenWi-fi antennasComputer softwarePull-string recharger KeyboardPlastic caseVideo cameraData ports

$100 Laptop engineer Chris Blizzard at window

To ensure the laptop is robust and can be maintained as easily as possible it omits all moving parts. It has no hard drive, CD or DVD drive. As it also packs a low power processor it has no cooling fans.

Storage: Instead of a large hard drive the laptop has 1GB of flash memory, similar to that used in some digital cameras.

The memory can be expanded using an SD memory card slot underneath the screen or by plugging in peripheral devices through the USB ports.

Files can also be backed up on to a "school server" - a larger computer installed in a classroom - or via an online system provided by search giant Google.

Processor: AMD 433 MHz
Memory: 256MB SDRAM
Storage: 1GB Flash

Processor: The chip, made by AMD, is much slower than most in today's PCs, operating at a speed of just 433MHz. In comparison , some of today's high performance machines have multiple chips with speeds of up to 3GHz.

The off-the-shelf processor is designed to be energy efficient. Unlike a standard chip, which remains active even when nothing changes on screen, the AMD processor is able to shut itself down, only waking when it is needed. It has an inbuilt graphics card.

Wi-fi: To conserve as much battery power as possible the wi-fi adapter can operate even when the main processor is switched off or asleep. It is able to do this by having its own in-built low power chip. The adapter supports standard wireless protocols used in most homes and offices.

olpc screen showing doughnut
Different programs appear in the doughnut icon as they are opened
The laptop has a bespoke Linux operating system (OS) developed by leading open source software company Red Hat.

In contrast to sometimes costly proprietary software, open source software is free and allows users to access and alter the code. OLPC hopes some children will tinker with the code to develop new programs.

In comparison to standard operating systems (OS), it is very small when compressed, taking up just 130MB of space. By comparison, Windows XP takes up around ten times that amount, requiring 1.5GB of hard drive space.

Its user interface is known as Sugar. At the centre of the screen is a customised icon surrounded by a white circle known as the "doughnut". As different programs are opened icons appear in the doughnut.

Different programs take up different amounts of space on the ring depending on their size and system requirements. Because of the machine's limited memory, when the doughnut is full, no more programs can be opened.

It includes standard programs such as a web browser based on Firefox; a word processor able to handle most common document types, including Microsoft formats; a PDF reader and media player. In addition, it comes with games, a music creation tool and drawing programs.

rabbit ears antennas
The wi-fi antennas are also known as rabbit ears
One of the most recognisable features of the laptop is the dual wi-fi antennas, known affectionately as "rabbit ears". These boost the range of the wireless connection by between two-and three-times the normal range.

A test done in the outback of Australia under ideal conditions showed that two laptops could communicate more than 2km (1.2 miles) apart. In reality, the range will be much shorter than this.

Using standard wireless protocols, the laptops are automatically able to form a "mesh network" where each machine acts as both laptop and router, able to pass information between computers.

If one laptop is switched on in range of an internet connection (usually at a local school) all other laptops on the network can share the access.

Those computers furthest from the connection will have the lowest internet speeds. If there is no internet access, the laptops can still share data, video and information through the mesh.

It does not have an Ethernet port for use with wired internet connections .

Screen showing black and white icons

The laptop has a low power dual-mode display, allowing children to toggle between colour and black-and-white screens.

Designed for use in outdoor classrooms, the full-colour transmissive mode is similar to any other Liquid Crystal Display (LCD), but in ultra low-power black-and-white mode the screen is readable in direct sunlight.

Many companies are interested in using the technology in standard laptop displays.
19cm (7.5 inches) LCD display
Colour mode: Resolution 800x600 (133dpi); power consumption 1 watt
Black and white mode: Resolution 1200x900 (200dpi); power consumption 0.2 watt; sunlight readable

The screen can also swivel around to convert the laptop into an e-book or a games console.

It is also easily maintained. For example, a faulty backlight - a common complaint on aging laptops - can be replaced by undoing two screws.

'Yo-yo' power supply

A range of power supplies are available to countries buying the laptop. Two choices of rechargeable battery are offered with different chemistries. Both cost $10 (5) to replace and hold their charge for at least four-times the amount of time as a normal laptop battery, according to OLPC.

For areas with an electricity supply, the computer can be used with an 18W power adapter.

In areas without access to the grid, various contraptions have been designed to plug directly into the laptop including a solar panel, a hand crank (similar to those used on wind-up radios), a foot pedal and a pull-string recharger, similar to a starter cord on a lawnmower.

The pull-string gives 10 minutes of charge for every minute of pulling. Group recharging stations can also be bought for schools where multiple batteries can be hooked up to solar panels or car batteries.

The sealed rubber keyboard is child-sized and waterproof
The sealed green rubber keyboard is waterproof and its size is designed for a child's hands. As well as being offered in a standard QWERTY layout it has various configurations for different languages such as Thai, Arabic, Spanish, and Urdu.

In addition, the keyboard does away with low-use keys such as Caps Lock. In their place are new buttons such as the "geek key" or "view source", which allows children to quickly see the underlying code used to write the program running on screen.

A "grab" key allows children to pan and scroll around the screen while a slider key on the top left-hand-side of the keyboard allows users to quickly see who else is part of the mesh network, who they are working with on collaborative projects and which of their friends are online.

Keys either side of the screen below the inbuilt speakers are used for gaming and reading e-books. A touchpad allows children to control the cursor and can be used as a drawing tablet using a stylus or the back of a pen.

Green and white plastic case
The hard-wearing plastic case is waterproof and dustproof
The hard-wearing green and white plastic case is designed to be as waterproof and dustproof as possible for children walking to and from school.

When it is closed the wi-fi antennas lock the laptop and cover the only external openings, the data ports.

The laptop has been dropped from 1.6m (5ft), with the antennas up, with no breakages. According to OLPC, the laptop keyboard has also been dunked in water for 10 minutes with no effect.

The entire package is approximately half the weight and size of a standard laptop. Holes either side of the carry handle allow children to tie a scarf or string to the laptop so it can be carried over the shoulder.

It also features a coloured XO on the back cover. There are 400 different colour combinations so that children can easily distinguish their laptop.

In the future, the plastic case may be swapped for durable rubber.

Camera on RHS of screen

Situated on the right hand side of the screen, the still and motion capture camera allows video chat across the mesh network and the internet.

With a resolution of 640x480, the colour camera can also be used to take photographs or as a light meter for school projects.

Rabbit ears cover usb ports when case is closed and ears down
The rabbit ears cover the usb ports when the case is closed

Three USB ports will make it possible to connect a variety of peripherals including a mouse or larger keyboard. A microphone input and a line output will allow children to play music through external speakers and record sounds.

All of the ports are covered by the wi-fi antennas when the laptop is closed, preventing water and dust getting inside.

An SD memory card slot, underneath the screen can be used to expand the memory capacity or to load new software.

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