In the year 1979, both Sony and Philips corporations were on the verge to launch incompatible audio discs format when instead they decided to join hands and formulate a single industry standard disc format. Philips contributed to the physical design of the compact disc, which was quite similar to its previous laserdisc format. On the other hand, Sony’s contribution to this new development was in terms of digital encoding and error-correction code designs.

In the year 1980,both companies announced the CD-DA standard, which included specifications regarding sampling, recording and the physical format of present Compact Disk. Once the specification was set, both companies raced against each other to be the first to launch the compact disk in the market. However due to its extensive experience with digital electronics, Sony managed to beat the chase and introduced the first commercial CD featuring Billy Joel’s 52nd album, on 1st October 1982.

The noted first use of gunpowder happened in the year 1132. However, the most historic known cannon belongs to 1282 and was found in Manchuria. A Chinese poet Xian Zhang had written the first description of cannon in his poem The Iron Cannon Affair. The use of cannons in various wars and invasions can be found in the history of many countries like China, Japan and Korea.

The war of Ain Jalut between the Mamluks and Mongols, it was known for using a form of explosive gunpowder. Much later the Mughal Empire developed many forms of cannons generation after generation. Fathullah Shirazi who worked for the great emperor Akbar is credited for developing the Volley Gun. In the thirteenth, fourteenth and fifteenth century, the use of cannons and its further developments happened very fast as wars increased during this period.

Modern air conditioning system was developed in the 19th century. It is a device or an appliance that stabilizes the humidity and temperature and uses a refrigeration cycle for cooling the atmosphere. Willis Haviland Carrier availed the credit of inventing the first large scale electrical air conditioning system in the year 1902. The system introduces by him was used widely in Asian and Middle Eastern nations. It was more common and popular among the capital cities and urban regions where people lived in small apartments or flats. They considered the air conditioning system as a necessity and not a luxury, which made it very popular.

Japanese made the compact system of air conditioning for domestic purpose in two type namely window systems and split types. Split type air conditioning system is more effective and expensive when compared with the other type.

There are several versions of Bluetooth and the first Bluetooth in the market for use was introduced in the year 1999 known as Bluetooth1.0. With major developments in last few years, Bluetooth services have gone major changes. There are no more failures in data transmission and pairing of devices and the speed of data transfer is much higher. Due to the cost of development and research, initially only high priced gadgets used Bluetooth technology. But most companies have Bluetooth as a common feature in the majority of the phones and laptops. It makes data transfer and sharing faster and much more convenient.

A blog may contain text, images, web pages, links to other blogs, etc. Most of the blogs are interactive; allowing as well as expecting the visitors to leave their opinion or comment. They provide information and comments on a particular subject. There are few blogs that focus on art – art blogs, photographs and photography – photo blog, music and songs – mp3 blogs, graphics and videos – video blog, etc.,

Blogs range from a simple web journal just for the sake of entertainment to a big business blog and several types of blogs include personal blogs, corporate blogs and topic blogs. Recently blogs are used for money making through posting advertisement for online merchants.

In 2003 when blue ray DVD was first introduced in the market, there were no movies that were released in the same format. However after major wars between HD and Blu ray technology, Blu ray had carved a good market share for itself. Warner Bros, the major distributor and producer, decided to release the movies under the banner only in Blu ray with effect from May 2008. The effectiveness of Blu ray discs and the use of the technology have triggered many production houses to release movie DVDs in this technology. Around 3300 titles have been released only in Japan itself where as Australia has about 1500 titles in Blu ray discs.

The development of inexpensive sources of electricity in the latter half of the century enabled the use of arc lights on a large scale. A generator producing direct current power known as the Dynamo was one of the first developments that catapulted the chain of events. The installation of arc lights thereafter became widespread in places such as mills, factories, railway stations etc.

American scientists worked simultaneously to make major contributions in the improvement of arc lights. The first commercial arc lamp was made in the United States in the year 1877 by William Wallace. Around the same time, a pioneering American scientist, Charles Brush invented a way to operate multiple arc lights using a single generator thus saving on the electricity used. Many more lighting systems which went easy on power were consequently introduced.

Arc lights have come a long way today. They have now found applicability in more advanced functions like testing of aerospace materials and hardening metal surfaces rather than traditional lighting purposes for which they were originally developed.

The term biometrics has been derived from Greek words bios – means life, and metron – means measures. It is the study of development of automatic methods for identification and validation of unique physical and behavioural traits of individuals. The term is also used to refer to self assessment through automated methods.

The term biometrics is also used as a noun to refer to the characteristics of particular measurement and as an adjective to explain the products, technologies and measurements in this field. For instance, assessment and identification of unique physical characters like eye retinas, facial patterns, finger prints, DNA sequences, hand measurements, etc. Sometimes voice is also included in the behavioural pattern and characteristics.

However, biometric systems have several technical limitations and associated with certain error ratings. Since the system is used for observing the behavioural pattern, it should not interrupt the privacy and freedom of an individual. Misusing the technology may lead to opposite side effects. Similarly, the information derived from the examination should be safeguarded in a proper way otherwise criminal minds may aggravate the problem of identity theft and steal valuable information.

The crossbows however were not very powerful till the invention of composite bows around the 1400s. Composite bows were made of materials such as horn, sinew etc. which enhanced the strength and elasticity of the weapon. Prior to the invention of composite bows, materials such as wood and bone were used for its construction. However, the earlier bows were much lighter and easier to carry. Besides, the process of making the composite bows was quite long and tedious. It took as long as six months for the glue to dry up hence making the procedure even more time consuming. Somewhere around the end of 1400, the use of steel to construct bows came into practice. It brought more strength and durability to the bow and also to the entire weapon as a whole. Romans are also said to have developed their own version of the Crossbow.

Douglas Engelbart contributed greatly towards the changing the working method of computer. He invented several user friendly tools that can be used by everyone. Computer mouse was the most prominent tool among his invention. Hypermedia, Video teleconferencing, windows, email, internet, groupware, etc are his other inventions.

Most conventional type of mouse has two buttons at left and right side. Left side button of the mouse is used frequently.

It was named mouse because the wire connected and coming out of the mouse resembles the tail of a real mouse. But with recent development, the wireless mouse is designed.

Mouse can be classified into three types and includes the following.

• The Mechanical mouse – operated with a ball to move the cursor on the screen. This type of mouse require a flat surface called mouse pad.
• The optomechanical mouse is the mixture of optical and mechanical technology. It uses the ball for movement, but also detects the optical movement.
• The optical mouse used laser in form of optical sensor for detecting the movement of mouse.