Computers manipulate electronic data according to a set of instructions called programs. It is this feature of computers that distinguishes them from calculators and makes them highly versatile. A computer program can include instructions that may vary from a few scores to a billion or even more. It may take years for a team of computer programmers to develop a program for an internet browser. The program may still contain some errors called bugs. Some of the earliest models of computers were as large as a room. Modern computers use integrated circuits (ICs) to perform their complex functions. These circuits have helped in developing compact and light weight variants of computers. Some modern day simple computers are small enough to be fitted into a wrist watch.


The one feature that distinguishes a computer from other machines is their ability to be programmed. It simply means that they can store a set of instructions in their memory and execute them later as per the user's requirements. A computer's central processing unit (CPU) directs its various components and establishes coordination in them. Technological advances have made it possible to develop portable computers. These portable computers are called laptops or notebook computers. These devices generally do not weigh more than 18 pounds or 8 kilograms. They usually sport a liquid crystal display (LCD) and a full QWERTY keyboard. Many variants of portable computers like personal digital assistants (PDAs) and internet tablets are also available in the markets.


The first true portable computer, titled GRiD Compass 1101 was developed by Bill Moggridge in 1980. Apple released Macintosh Portable in 1989. It was the company's first computer which was powered by a battery. In 1994, IBM released its PowerPC notebook that ran on a UNIX based AIX operating system. Most present day portable computers feature a PC card, and a 30 cm active matrix display with a resolution of not less than 1024 x 768 pixels. The devices usually feature an integrated video and sound chip. Newest models of notebook computers use lithium polymer batteries which are more powerful than earlier lithium ion or nickel metal hydride batteries.


Leading manufacturers of computers like Sony, Toshiba and Acer have released several high performance laptops in the markets. VAIO is among the most successful models of Sony laptops. The word VAIO is an acronym for Video Audio Integrated Operation. The device sports Sony's proprietary XBRITE display that provides about 1.5 times better brightness than traditional LCD displays. The device comes loaded with Windows Vista operating system. The AR series of the device was first to feature a Blu-ray disc burner. The device's SZ series feature an Intel GMA 950 graphics chip that shows high resolution graphics.


Toshiba's many models of notebook computers have registered good sales. Qosmio, Tecra and Portege are among the best selling models of Toshiba laptops. The Portege M400-1115E uses an Intel Core Duo T2400 processor. The device is equipped with 80 GB of hard disk drive and weighs 2.1 kg. It runs on a Windows XP Tablet Edition operating system. It sports a 12.1" XGA display. The device has support for Bluetooth and WiFi connectivities and is available in titanium silver colour.


Acer's Aspire series of notebooks have got wide acceptance among the users. The notebook is counted among the best selling Acer laptops. The device features a 'Pebble' design and is intended for use by general users. Aspire 4710 comes equipped with Gigabit LAN, 160 GB hard disk drive and 1 GB RAM. It operates on a LINUX platform. Manufacturers like Hewlett-Packard, Dell, Compaq and Lenovo have also rolled out some highly successful models of notebooks into the markets. Laptops have given new dimensions to computing. The devices have become a must have for many senior executives and professionals.

About the Author: Jayson Pablo, a dedicated writer of Rupizcompare.co.uk which provide information on cheap computers and cheap laptops.