What's the difference between notebooks, netbooks and ultra-mobile PCs?

Notebook computers are lighter than the laptops we looked at in the previous section. They usually have screens ranging from 12 to 17 inches (30.5 to 43.2 centimeters) and weigh around 5 to 6 pounds (2.3 to 2.7 kilograms). Ideally, a notebook computer has the same processing power and features as larger laptop computers. Many manufacturers charge a premium price for the convenience of a small computer that packs a big punch.

The Lenovo ThinkPad X300 is a notebook computer. It has a 13.3-inch (33.8 centimeter) screen and weighs only 3.2 pounds (1.5 kilograms), making it a lightweight in the notebook category. When closed, it measures only .9 inches (2.3 centimeters) thick. It also has many of the features you'd find in a typical laptop computer: a WiFi card, a Bluetooth antenna, a dual-core processor, 1 gigabyte (GB) of RAM and a 64-GB solid-state hard drive. It also has a DVD drive and an integrated Web camera. It comes with the Windows Vista operating system.

Netbook computers are relative newcomers to the computer market. The general definition for a netbook computer is that they are smaller, less powerful and less expensive than notebook computers.

When they first began to get attention in early 2008, netbooks seemed to contradict the popular philosophy in the computer market. For many years, the prevailing strategy for computer consumers was to find the fastest, most powerful computer in their price range. But consumers are beginning to understand that they don't necessarily need a bleeding-edge computer for most of the tasks they perform. And as the Web takes a more prevalent role in computing, the processing requirements for consumer computers become less demanding.

Though people disagree on specific metrics for netbooks, in general they have screens smaller than 12 inches (30.5 centimeters) and weigh only one or two pounds (.5 to .9 kilograms). Typically they cost between $300 and $600. An example is the Asus EEE PC 4G. It weighs two pounds (.9 kilograms) and has a seven-inch (17.8 centimeter) screen. The processor is an Intel Celeron M 353/630 megahertz chip and it has 512 megabytes of RAM. It comes with a 4 GB solid-state hard drive and costs around $400.

Tha­t leaves us with the ultra-mobile PC (UMPC). Technically, the term applies specifically to a Microsoft product. It's a tablet computer -- imagine a computer screen without a keyboard. The interface for most UMPCs is a touchscreen with a stylus and an array of physical keys set along the sides of the screen. These tablets tend to be light like netbooks and feature small screens in the 4- to 7-inch (10.2- to 17.8-centimeter) range.

Some UPMC models have a full QWERTY keyboard that you can slide out from under the screen. Others rely exclusively on the touchscreen interface. Most run on the Windows Vista operating system. While UMPCs are more portable than notebooks, they are more expensive than netbooks.

Samsung's Q1UP-XP Ultra Mobile PC is a good example. It has a seven-inch (17.8-centimeter) LCD touchscreen display and weighs just two pounds (.9 kilograms). It has a split QWERTY keyboard with keys on either side of the screen. It's also WiFi and Bluetooth compatible. The computer has a microphone and can serve as a voice over Internet protocol (VOIP) device. The price tag for the Q1UP-XP at the time of this writing is $1,299.

But some people use the term UMPC to describe all small computer devices, including netbooks. Others use it to differentiate pricey mobile computers from inexpensive netbooks. For example, while Apple calls its MacBook Air product a notebook, others say it doesn't fit the notebook category. The Air is thin enough to fit inside a standard manila envelope and features a 13.3-inch (33.8-centimeter) LED backlit display. But its processor is less powerful than other MacBook models. It has limited storage space and only a few ports. The Air also costs a pretty penny: the starting price is $1,799.

The Air's design, processing power and price make it tricky to categorize. That's why some journalists use the term UMPC to describe devices that are portable but are more powerful and expensive than netbooks. Using this terminology, a netbook is small, inexpensive and has modest processing power. A UMPC is small, more expensive and generally has a better processor than a netbook.

New products will blur the lines further between netbooks, notebooks and UPMCs. At CES 2009, Asus showed off the Eee T91 and T101H computers. These devices are a cross between tablets and netbooks. They feature screens mounted on a pivot -- you can turn the screen around and fold it back over the keyboard. A touchscreen interface allows you to use the netbook as a tablet PC. These products will hit the market in 2009. At the time of this article, Asus has not made an official announcement regarding the price of these products.

Smartphones also have the potential to make the mobile computing landscape more confusing. As smartphones become more powerful, they begin to fill the same niche as netbooks. In general, smartphones range in price from around $199 to more than $900. They're very portable and multifunctional. Companies that design applications for smartphones may incorporate more cloud computing strategies in their products in the near future.

At the same time, some netbook manufacturers are partnering with cell phone carriers to include cellular technology in their products. Some netbooks can access 3G, EDGE and other cellular networks for data transfers. While data transfers using these protocols tend to be slower than WiFi, the infrastructure for cellular networks has a stronger foundation than WiFi networks.

One thing is for certain: mobility is important. People want to be able to access applications and data any time and anywhere. They may want a device that has its own spacious hard drive or a netbook they can use to log into a remote data storage service -- or they may not know what they want.

While netbooks accounted for a significant percentage of computer sales during the 2008 holiday season, the return rate on netbooks is relatively high. That may be due to consumers misunderstanding the purpose of netbooks. The devices aren't as powerful as notebooks, laptops and desktop computers. They also tend to have smaller keyboards and some people have trouble typing during an extended computing session. And people who choose netbooks running on Linux may become frustrated with an unfamiliar operating system (OS).

Despite the return rates, the popularity of netbooks and other portable computing devices continues to grow. The convenience of these devices coupled with tough economic times may mean the days of the super-powerful and expensive desktop PC are numbered.

To learn more about portable computers, take a look at the links on the next page.