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Course - 1 : Introduction to Programming

Link to the course: Link.

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ROUGH NOTES (!)
Updated: 17/06/2026

[Introduction to Computers]

Components of a Computer

Consider the inside of a desktop system.

We have the Motherboard:

The Motherboard hosts the Central Processing Unit (CPU) or the Processor. (In the pic, the CPU is covered by the fan).

The Processor has two important units:

• Arithmetic and logical unit: It does all the operations.

• Control unit: It does all the controlling mechanisms.

We see two slots:

The slots are for holding the memory unit, which is used for storing data while the processor is under execution.

We also see buses/paths:

A device can use buses or paths to communicate with the CPU or with other devices.

We also have SMPS (which stands for Switched-Mode Power Supply):

The SMPS regulates the power supply to the system.

We can also use an external hard disk:

We can use an external hard disk for permanent storage of data.

Other devices can also be connected using PCI (Peripheral Component Interconnect) slots.

How does a Computer work?

A computer is a device that takes data as input, does some operations on it based on a set of instructions called a program, and then returns an output.

Eg: Suppose you are using a Word Editor. Suppose you want to change the font of your text. To do that, you first give an input. You select the lines you want to change by using the mouse, and select the right font you want to apply. The computer does the task and you can see the output.

Eg: Suppose you are playing a video game. Suppose you want to make a character jump on the screen. You have your input device, a joystick, you make certain movements, and you see the output on the screen.

The inputs to a computer can come from different devices (eg, mouse, keyboard, scanner, microphone, etc).

The output of a computer can be presented in various forms (it could be written onto a new file, or sent to a printer, or sent to the display device, or sent to a speaker, etc).

All these physical devices, which we can see and touch, are called hardware.

The set of instructions we give to a computer to do a specific task is called software.