Answers:
The basic parts of a desktop computer are the computer case, monitor, keyboard, mouse, and power cord.Each part plays an important role whenever you use a computer.
computer case:
The computer case is the metal and plastic box that contains the main components of the computer. It houses the motherboard, central processing unit [CPU], power supply, and more.
computer cases come in different shapes and sizes. A desktop case lies flat on a desk, and the monitor usually
sits on top of it. A tower case is tall and sits next to the monitor or on the floor. The front of the case usually has an on /off switch and one or more optical drives.
Monitor:
The monitor works with a video card, located inside the computer case ,to display images and text on the screen. Newer monitors usually have LCD [liquid crystal display] or LED [light-emitting diode] displays.These can be made very thin, and they are often called flat-panel displays. Older monitors use CRT (cathode ray tube) displays. CRT monitors are much larger and heavier, and they take up more desk space. Most monitors have control buttons that allow you to change your monitor’s display settings, and some monitors also have built-in speakers.
Power cord:
The power cord is the link between the power outlet and the power supply unit in the computer casing. If the power cord is not plugged in, the computer will not power on. To protect your computer from voltage spikes, you can plug the power cord into a surge protector. You can also use an uninterruptable power supply (UPS), which acts as a surge protector and provides temporary power if there is a blackout.
Keyboard:
The Keyboard is one of the primary ways we communicate with the computer and enter data. There are many different types of computer keyboards, such as wired, wireless, ergonomic, and multimedia. Although there may be differences in the location of some keys or features, keyboards are very similar and allow you to accomplish basically the same tasks.
Mouse:
The mouse is a peripheral that is known as a pointing device.It lets you point to objects on the screen, click on them and move them.
There are two main types of mice: optical and mechanical. The optical mouse uses an electronic eye to detect movement and is easier to clean. The mechanical mouse uses a rolling ball to detect movement. Generally, a mechanical mouse is less expensive, although it may require regular cleaning to keep it working properly.
Traditionally, a mouse connects to the computer using a USB or PS/2 connection. However, you can also buy a wireless mouse, which can reduce clutter on your desktop.
Mouse alternatives:
There are other devices that can do the same thing a mouse can do, but with a different look and feel. Many people find them to be easier to use, and they also require less desk space than a mouse. The most common mouse alternatives include:
Trackball:
A trackball has a ball on top that can rotate freely. Instead of moving the device like a mouse, you can simply roll the ball with your fingers to move the pointer. some mobile devices have miniature trackballs that can be controlled with your thumb.
Touchpad:
A touchpad (also called a track pad) is a touch-sensitive pad that lets you control the pointer by making a “drawing ” motion with your finger. Touchpads are common on laptop computers.
Light pen:
It is light sensitive input device shaped like a pen.
Barcode:
A barcode is an optical machine-readable representation of data relating to the object to which it is attached.
CD and CD ROM (Compact Disk Read Only Memory):
Compact disc (CD) is a digital optical disc data storage device. Its format was originally developed to store and play sound recordings only (CD-DA), but was later adapted for storage of data (CD-ROM). Several other format were further derived from these, including write-once audio and data storage (CD-R), rewritable media (CD-RW), Video Compact Disc (VCD) Super Video Compact Disc (SVCD), Photo CD, Picture CD, CD-i, and Enhanced Music CD. Audio CDs and audio CD players have been commercially available since October 1982.

Answer:
Today, there are many everyday devices that are basically specialized computers, even though we don’t always think of them as computers.Here are a few common examples:
Tablet computers:
These use a touch-sensitive screen for typing and navigation. Because they don’t require a keyboard or mouse, tablet computers are even more portable than laptops. The iPad is an example of a tablet computer.
Mobile phones:
Many mobile phones can do a lot of things computers can do, such as browsing the Internet and playing games.These phones are often called smartphones.
Game consoles
A game console is a specialized kind of computer that is used for playing video games.although they are not as fully featured as desktop computer, many newer consoles, such as the Nintendo they you to perform nongaming tasks like browsing the web.
TVs
Many TVs now include applications [or apps] that let you access various types of online content. for example, you can view your Facebook news feed or watch streaming movies on Netflix.

Answers:
 Analog computer:
An analog computer is a form of computer that uses the continuously-changeable aspects of physical phenomena such as electrical, [l] mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computer represent varying quantities incrementally, as their numerical values change
Digital computer:
A digital computer is machine that stores data in a numerical format and performs operations on that data using mathematical manipulation.This type of computer typically includes some sort of device to store information, some method for input and output of data, and components that allow mathematical operations to be performed on stored data. Digital computer are almost always electronic but do not necessarily need to be so.
Hybrid Computers:
A hybrid computer is a type of computer that is designed to provide the features and functions that are found by both the digital and the analog computers. A hybrid computer system offers a much cost effective method that is used to perform complex simulations.
Classification of computers:
When most people hear the word “computer,” they think of a personal computer such as a desktop or laptop computer. However, computers come in many shapes and sizes, and they perform many different functions in our daily lives. When you withdraw cash from an ATM, scan groceries at the store, or use a calcuator, you’re using a type of computer.
Desktop computer:
Many people use desktop computer at work, home, school, or library.They can be small, medium or large in style and they usually sit  on a desk. Once you add a monitor, mouse, and keyboard, you have what is typically Known as a desktop computer.
Most desktop computer are easy to upgrade and expand or add new parts. Another benefit of desktop computer is the cost. If you compare a desktop and a laptop with the same feature, you will most likely find that the desktop computer is priced lower.
Some desktop computers have a built-in monitor to save space. These are often called all-in-one desktop computers. 
Laptop computers:
The second type of computer you may be familiar with is a laptop computer, or a laptop. Laptops are battery-or AC-powered personal computers that are more portable than desktop computers, allowing you to use them almost anywhere.
Because a laptop is smaller than a desktop, It’s more difficult to access its internal components This means you may not be able to upgrade them as easily as a desktop. However, It’s usually possible to add more RAM or a larger hard drive.
A laptop computer is sometimes called a notebook computer because of its  size.
Servers:
A  servers is a computer that serves up information to other computer on a network. Many businesses have file servers that employees can use to store and share files. A server can look like a regular desktop computer, or it can be much larger.
Server also play an important role in making the Internet work. They are where webpages are stored. When you use your  browser to click a link, a web server delivers the page you requested.
Micro computer;
A microcomputer is a small, relatively inexpensive computer with a microprocessor as its central processing unit (CPU).
Micro processor:
A microprocessor incorporates the functions of a computer’s central processing unit (CPU) on a single integrated circuit (IC), or at most a few integrated circuits.
Minicomputer:
A Minicomputer is a digital computer of medium power, more powerful than microcomputer but less than a mainframe. Minicomputers are mostly used for general businesses application and by large enterprises in department level operations.
Main Frame Computer:
Mainframe computers (colloquially referred to as “big iron”) are computer used primarily by corporate and governmental organizations for critical applications.

Answers: Hardware:
Hardware is any part of your computer that has a physical structure, such as the computer monitor or keyboard.
Software:
Software is any set of instructions that tells the hardware what to do. It is what guides the hardware and tells it how to accomplish each task. Some examples of software include web browsers, games, and word processors such as Microsoft Word.
The first electronic computer, the Electronic Numerical Integrator and Computer (ENIAC), was developed in 1946. It took up 1,800 square feet and weighed 30 tons.

Answers: The invention of integrated circuit brought us the third generation of computers. With this invention computers became smaller, more powerful more reliable and they are able to run many different programs at the same time. In 1980 Microsoft Disk Operating System (MS-Dos) was born and in 1981. IBM introduced the personal computer (PC) for home and office use. Three years later Apple gave us the Macintosh computer with its icon driven interface and the 90s gave us Windows operating system.
As a result of the various improvements to the development of the computer we have seen the computer being used in all areas of life. It is a very useful tool that will continue to experience new development as time passes.

Answers:  This generation of computer used transistors instead of vacuum tubes which were more reliable. In 1951 the first computer for commercial use was introduced to the public; the Universal Automatic Computer (UNIVAC I). In 1953 the International Business Machine (IBM) 650 and 700 series computers made their mark in the computer world. During this generation of computers over 100 computer programming languages were developed, computers had memory and operating systems. Storage media such as tape and disk were in use also were printers for output.