Environmental pollution is the release of environmental contaminants, generally resulting from human activity.

Transfer of large amount of data from one computer to another has always created problems, one of main reason being non-availability of suitable data storage device. To be precise, Storage mediums like floppy, CD and even Email have always failed during urgency due to their problem causing ability like small storage space or time-consuming ability for data transfer.

A possible solution to end this problem is use of zip drive. With up to 250MB capacity we can store everything we want and more on it. But in order for a proper transfer process to take place, both the computer systems must have zip drives. In addition, it more expensive compared to old floppy disk system. So what is the remedy to all these problems?

Pen Drive is the solution to the problem. Pen Drive can hold more data compared to floppy disk and Email space. Basically, Pen drive is a small key-ring-size device that can be used to easily transfer files between USB-compatible systems. It is accessed through the USB port on the computer. It has a capacity to hold data ranging from 11 to 350 floppy disks depending on the memory stick you choose. You can transfer data faster and easier than ever before. Pen drives are faster than downloading data via e-mail and much easier than using boxes of floppies. They are no bigger than the length of your finger, but hold data from 16 MB to I GB.

USB pen drives provide data, music and video transfers and storage with plug-and-play ease. The best feature of Pen Drive is that it doesn`t require any software to work, enabling the process of reading, writing and copying to or from a disk drive simple. Furthermore, it also doesn`t require any battery to operate. Hence, a pen drive is totally portable. Attach it to your key chain, belt, or wear it around your neck.
Basics about universal serial bus (USB) required for Pen drive.

USB
USB is an external peripheral interface standard developed by the computer industry to allow communication between a computer and external peripherals (digital device) over a cable using bi-serial transmission. Usually, digital cameras and memory card readers connect to the USB port on a computer. USB card readers are typically faster compared to cameras or readers that connect to the serial port, but slower than those that connect via FireWire.

The USB port is usually found at the back of the PC. It is a narrow socket around 1cm wide and 0.5cm high. You can plug a USB pen drive only into USB port. In some PCs, the USB port is located on the front below the CD-ROM drive.

Note:
For Windows 2000, XP, or ME USB driver need not be installed manually as the operating system will do it automatically. But, in case of Windows 95/98/98SE, drivers need to be installed manually (the driver is supplied along with the drive).

How to use it?
To transfer required Data of a P.C into Pen drive or vice-versa, simply plug the Pen drive into the USB port of your PC. The operating system will automatically detect installation of a new device and a new drive will be created. The operating system can access your pen drive just like any ordinary hard disk drive.

Now, Copy all the required files you want into the `new` drive and wait for the response by the Pen drive--indicated by read/write LED on the pen drive, to stop flashing and then disconnect it. Your files are now safely stored on your pen drive. If you want to copy these files to another PC/ Mac, just plug the drive in the new machine, wait for it to be detected and copy the files.

Working and cost
The working of Pen drive is based on flash memory. The flash memory-a type of EEPROM (Electrically Erasable Programmable Read Only Memory) chip.

Note:
Basically, EEPROM is a type of ROM that can be erased electronically and reprogrammed in-circuit (or with a device programmer) consisting of a complex grid of columns and rows. Hence, bytes (words) of an EEPROM can be erased individually.

The main reason why flash memory is quicker than older EEPROM is that entire banks can be erased at a time and subsequently rewritten.

The 32MB pen drive costs around $15, while the 1GB pen drive costs as high as $100; however, the purchase is worth the money.

Transparent pen drive
Flash Dio is a transparent pen drive. Frankly speaking, there is hardly any difference between the two except for few new features such as extra protection for write/delete switch from accidental erases.

Today, `Virtual Reality` is used in different ways and often in a confusing and misleading manner. Jaron Lanier, founder of VPL Research (1989) was the first man to term `Virtual world or Artificial world` as `Virtual Reality` (VR). This was followed by other related terms such as `Artificial Reality` by Myron Krueger, 1970s, and `Cyberspace` by William Gibson, 1984. And currently, this is known by the name of `Virtual Worlds` and `Virtual Environments`. Besides this, virtual reality also got popularized by the movie The Lawnmower Man and research in Virtual Reality reached its peak in 1990 with the help of non-fiction book Virtual Reality by Howard Rheingold.
Virtual reality (abbreviated as VR) is fundamentally an attempt to create realistic 3 dimensional world. This 3D world makes interaction of humans with computer possible. A user can interact with virtual environment with the use of standard input devices such as a keyboard and mouse or through devices such as head mounted display (goggles), special gloves, earphones, and/or full-body wiring. Thus, with the aid of specially designed transducers and sensors, users interact with displayed images, moving and manipulating virtual objects, and performing other actions in a way that engenders a feeling of actual presence (immersion) in the simulated environment.

CREATING VIRTUAL REALITY:

Head-Mounted Display (HMD)
Head mounted device was the first device to create, and provide its wearer with unseen world of virtual reality. In 1965, Evans and Sutherland first introduced head mounted display. But unfortunately, it was commercially available only after 20 years by the name "Eyephone" system.
HMD device consist of two miniature display screens and an optical system. These two components channel the images from the screens to the eyes, presenting a stereoscopic imaging. Others use a single larger display to provide higher resolution, but without the stereoscopic vision.
HMD provides virtual images by continuously tracking the position and orientation of the user`s head. This allows viewer to look around and walk through the surrounding virtual environment.

BOOM
The Binocular Omni-Orientation Monitor (BOOM) from fakespace is a high-resolution stereoscopic viewing device that enables interactive and real-time viewpoint control of camera or computer-generated 3D environments. The main advantage of BOOM is that it has the ability to generate better images compared to HMD.
The BOOM (Binocular Omni-Orientation Monitor) generates virtual images by using sensors in the links of the arm that holds the box (the box incorporates screen and optical system). The user looks into the box through two holes to experience virtual world.
When a user releases the BOOM, another person can view the same images from the same perspective, which is another advantage over HMDs.

Cave Automatic Virtual Environment
The CAVE is an immersive virtual reality facility designed for the exploration of and interaction with spatially engaging environments. Basically, the CAVE`s comprises of four projection surfaces on which images are projected with uniquely immersive design. In addition, including projection on the ceiling gives a fuller sense of being enclosed in the virtual world. Furthermore, projection on all six surfaces of a room allows users to turn around and look in all directions. This allows user to interact with world in ways never before possible, which is necessary for full immersion.

VRML

The most exciting development in the field of virtual world is the upcoming concept of VRML (Virtual Reality Modeling Language) on the World Wide Web. VRML is an open, platform-independent file format for 3-D graphics on the Web. In other words, VRML allows to create "virtual worlds" networked via the Internet and hyperlinked with the World Wide Web. These 3-D "worlds" can contain objects that link to 3D world, documents and other interactive elements.
Since virtual environment can represent any three-dimensional world that is either real or abstract. An immersive visualization can be applied everywhere starting from educational field to industrial field.
Currently, virtual reality is used for training in a variety of areas, such as military, medical. It is also used for equipment operation, education, design evaluation (virtual prototyping), architectural walk-through, human factors and ergonomic studies, simulation of assembly sequences and maintenance tasks, assistance for the handicapped, study and treatment of different types of fear (e.g., fear of height or animal), entertainment, etc.

Conclusion

Virtual reality has been gaining too much of hype since its inception, and in many cases more effort has been put on the development of new equipment and software rather than on the evaluation of whether VR accomplishes its stated goals. As a result of this, VR technology has not got sufficiently developed for economical use in work settings. For instance, Virtual reality has been heavily criticized for being an inefficient method for navigating non-geographical information.
But at the same time, it has opened doors to provide realistic object and environment, with which a user can interact. Thus, it remains to be seen how researchers utilize the virtual reality technology to take current development to one step above to complete stated goa