Why our PC is lagging? Fact File 40


Answer is simple. It is loaded with data and hence memory loss. A good PC will open the page or down load a matter with a single click. To make the PC fast, we have to do something. These are the tips to make your PC fresh and active.

1. Do not save files and images in the Desktop. It is managed by the drive C which already contains too much data.

2. Save files in other drives like D, E etc.

3. Make separate folders like Personal, Video, Image, Song etc in the D and E drives and save the files in the folders. This will keep the drive clean to see and it is easy to find out the files. Also arrange the files based on Type so that similar files will automatically arrange in alphabetic order.

4. Remove old files, video, songs etc from PC and store it is CD or Pen drive.

5. Down load programmes only in D or E drives. Do not use Drive C for saving down loaded programmes. It will make the PC slow.

6. Do not keep large files like Video in PC. It will consume large space and also makes PC slow and hanging. Store videos in CD.

Let us see the PC cleaning methods
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Why Pen drive is more dangerous than CD? Fact File 39


Malware infection is very easy through the Pen drive when compared to the infection from a CD. Flash drive, the commonly called Pen drive is a small sized hard disk ranging from 2GB to 64 GB memory size. It is very convenient to carry the computer data in a pen drive so most of us use this device. Unlike CD, virus infection occurs at the moment when we insert the infected Pen drive into the USB port. Virus infection from a CD takes place only when we open or copy the infected files. So we get time to see whether there is any infected file or not. Some new generation malwares first get into the C-drive and from there, spreads the infections to other drives like D, E etc. So if this occurs, we have to format all the drives and the files will be removed permanently.

Antivirus programmes like K7 has Pen drive immunization facility so that we can immunize the pen drive to prevent the entry of virus from an infected computer. Like Pen drive, the SD card, MicroSD TF cards etc are also susceptible to virus attack.

Computer Virus is a program that infects some executable software of the computer and causes that software, when run, to spread the virus to other executable software. The virus may also contain a payload which performs other actions, often malicious. A Computer worm is the program which actively transmits itself over a network to infect other computers. It too may carry a payload. The difference between the Virus and Worm is that the virus requires user intervention to spread, whereas a worm spreads automatically. Infections transmitted by email or Microsoft Word documents, which depends on the recipient opening a file or email to infect the system, can be called as viruses rather than worms.

The first network-borne infectious programs, originated in multitasking Unix systems. The first well-known worm was the Internet Worm of 1988, which infected SunOS and VAX BSD systems. It exploited the security holes in the network server programs and started itself running as a separate process.

Some common Computer malwares are Trogen, Rootkit,Backdoor,Botnet,Non resident virus, Resident virus, BanCos,Gator,LegMir,Qhost, Multipartite virus etc. Commom Mobile phone virus are SpaSMS, Spim, Cabir, Duts, Skulls, Common Warrior etc.

Let us see these dangerous programmes and the methods of virus prevention

Continue reading “Why Pen drive is more dangerous than CD? Fact File 39”

How Animals see more than humans? Fact File 38


The Night time world is never closed for nocturnal animals. Unlike humans, many animals possess adaptations that allow them to see even when the night sky is very dark. Animals have developed amazing adaptations to their environments. Most nocturnal animals have large eyes relative to their body size. This adaptation, along with the ability to dilate their pupil far wider than humans can, maximizes the amount of light entering into the eye.

Not all animals see the world as humans do. For many animals, the world is seen in fuzzy shades of gray, or very “washed out” and pale colors. But some animals can see in total darkness, or even see colors beyond the visual spectrum, that humans have never seen. Still others can use binocular vision to spot prey from thousands of feet away.

Nocturnal mammals have rods in the retina with unique properties that make enhanced night vision possible. The nuclear pattern of their rods changes shortly after birth to become inverted. Inverted rods have heterochromatin in the center of their nuclei and euchromatin and other transcription factors along the border. The outer nuclear layer in nocturnal mammals is thick due to the presence of millions of rods  to process the lower light intensities of a few photons. Light is passed to each nucleus individually.

Many animals have a tissue layer called the Tapetum lucidum at  the back of the eye that reflects light back through the retina. This increases the amount of light entering into the retina. This is found in many nocturnal animals and some deep sea animals. This causes the phenomenon of eye shine in these animals. Tapetum lucidum is absent in human eye.The shining of eyes in Dogs and Cats in vehicle head light is due to this reflective retina.Some animals have Guanine crystals in the eye that shines and reflect light.

1. Dog and Cats – They have night vision and can see moving objects rather than the stationary ones. Their eyes are much more sensitive to movement. Dogs and cats are color blind and see only very pale shades of color but they have better peripheral and night vision.

2. At night , some snakes use Pit Organs to sense infrared rays from the prey. Pit organs can pick up infrared heat signals from warm objects in their surroundings.

3. Bees can see light between wavelengths 300 nm & 650 nm and they can see polarized light.

4. Bats can detect warmth of an animal from about 16 cm away using its “nose-leaf“.
Continue reading “How Animals see more than humans? Fact File 38”

Why Security system uses Infrared Camera? Fact File 37


Infrared camera is used to capture the image of a moving person in darkness as a measure of security. The surveillance systems used in home, office and commercial establishments uses infrared camera to monitor the premises. The infrared camera utilizes the infrared radiation generating from the body heat. The system senses the infrared and generates a video image of the moving person using the infrared camera. This device is sensitive to only the infrared range of the electromagnetic spectrum.

The system uses a Photocathode sensitive to infrared. The Photocathode consists of a thin layer of metal that can give out electrons by accepting energy from the infrared rays. The thin layer of metal is coated on a flat glass plate. A lens system is provided to focus the infrared light from the source into the photocathode plate. The metal coating in the photocathode is too thin so that when the infrared energy hits the front layer of the metal, electrons will be emitted from its back layer. Thus the photocathode generates an electron pattern based on the infrared photons hitting on the photocathode.

Continue reading “Why Security system uses Infrared Camera? Fact File 37”