4.How it is different from a smart phone or a cell phone

Like laptops, tablet computers are designed to be portable. However, they provide a very different computing experience. The most obvious difference is that tablet computers don't have keyboards or touch pads. Instead, the entire screen is touch-sensitive, allowing you to type on a virtual keyboard and use your finger as a mouse pointer. Tablet computers are mostly designed for consumers, and they are optimized for tasks like web browsing, watching videos, reading e-books, watching photos, and playing games. For many people, a "regular" computer like a desktop or laptop is still needed in order to use programs like Microsoft Word or Photoshop. However, the convenience of a tablet computer means that it may be ideal as a second computer. Below are some of the main features that you can expect with a tablet computer.

Solid-State Drives

Tablet computers usually use solid-state drives, which allow the computer to boot up and open programs more quickly. They are also more durable than hard disk drives.
Wi-Fi and 3G/4G: Since they are optimized for Internet use, tablet computers have built-in Wi-Fi. For a monthly fee, you can also purchase a 3G or 4G data plan, allowing you to access the Internet from almost anywhere.

Bluetooth

In order to save space, tablet computers have very few ports. If you want to use an external keyboard or other peripherals, they will often use a wireless Bluetooth connection

In comparison, a smart phone is a powerful mobile phone that is designed to run a variety of applications in addition to phone service. They are basically small tablet computers, and they can be used for web browsing, watching videos, reading e-books, playing games and more. Smart phones use touch screens and operating systems similar to those used by tablet computers. Many of them use a virtual keyboard, but others (such as the BlackBerry Curve) have a physical keyboard, which allows the entire screen to be used for display purposes. Internet access is an important feature of smart phones. Generally, you will need to purchase a 3G data plan in addition to normal cell service. Smart phones can also connect to Wi-Fi when it is available, which is usually faster than 3G. The differences between smart phones and a tablet PC are very few, such as larger screen area, extended battery life, higher computing power and memory capacity in tablet PCs.

5.Advantages or disadvantages of tabs over laptops and desktops

Advantages

1. Tablet PCs feature more mobility than traditional notebooks, due to the absence of built-in keyboard. They are also often more lightweight than most notebooks, and consume much less power. Also, handwriting can be much slower than traditional keyboard input when writing lengthy documents and emails. Due to the amount of hand resting directly on the screen, Tablets are also more susceptible to smudges and dirt collection.
   
2. A tablet sits somewhere between the smart phone and laptop in most areas, and flexibility is no exception. In many ways, a tablet can fill the role of a laptop and perform most, if not all, of the same functions. But, the tablet is also more versatile. Most can take photos, or shoot videos in addition to allowing video chat and conferencing. They also work nicely as e-readers (or in some cases the e-reader has evolved into a tablet) for accessing an entire library of books on the go. Some of these things are technically possible, but ridiculous in a practical sense with a notebook. 

Disadvantages

1. A tablet PC is generally more expensive than the mature technology of laptops, although prices are coming down slightly since they were first introduced (and are likely to come down further with the emergence of Apple’s iPad).
   
2. The ‘handwriting-to-text’ conversion does not always work the way we would like it to. Tablet PCs recognize a trained penmanship easier than the way you may write naturally. Just like speech-to-text systems it requires a trained style of speech to work properly.
   
3. The size may also be a disadvantage. As they are smaller than laptops this clearly means that the screen is smaller, possibly reducing the visibility function that laptops can provide. The keyboards are also smaller which could prove difficult for some people who already struggle with a laptop keyboard.