What is a Computer?

What is a Computer?

• A computer is an electronic device that operates under the control of instructions stored in its memory unit.
• It can accept data, manipulate it according to specified rules, provide information in a useful format, and store the results for future use.

Data, Information, and Program

• Data: a collection of unstructured facts, figures, and symbols that have not been processed by humans or computers.
• Information: processed and presented data in an organized manner.
• Program: a set of instructions that enable a computer to perform a given task.

Functionalities of a Computer

• Input: takes data as input and commands from the input device to the computer.
• Processing: processes the data and converts it into a useful format.
• Output: generates the output which is displayed by the computer to the user.
• Storage: stores the data/instructions in its memory and uses them as required.
• Control: controls all the above four steps.

Advantages of Computers

• No advantages are mentioned in the text.

Classification of Computers

• Computers can be classified by their size, speed, and computing power into:
  • Microcomputers
  • Minicomputers
  • Mainframe computers
  • Supercomputers

Microcomputers

• Also known as "computer of a chip" or "Personal Computers".
• Have less storing space and processing speed.
• Can be further categorized into:
  • Workstations
  • Desktops (Personal Computers)
  • Tablet PCs
  • Laptops
  • PDAs (Personal Digital Assistants)

Workstations

• Desktop computers used for engineering or graphic applications.
• Have more processor speed than personal computers, high-resolution graphics screen, a large amount of RAM, inbuilt network support, and a graphical user interface.

Spreadsheet Software

• Allows users to organize numeric data in a tabular form.
• Provides many mathematical, financial, and statistical functions.
• Examples: Lotus 1-2-3, Corel's QuattroPro, MS Excel.

Database Applications

• A collection of related information about a particular subject stored in a way that can easily be accessed, managed, and updated.
• Examples: Computerized banking system, Automated Teller Machine, Airlines, and Railway reservation system.
• Common Characteristics: Self-describing, Data exists permanently, multiple users can access the same data, and Data security protects the data from unauthorized access.

Relationship between Hardware and Software

• Hardware and software are mutually dependent on each other.
• Both must work together to make a computer produce a useful output.
• Software cannot be utilized without supporting hardware.