Unit 1: IT Systems – Comprehensive Study Notes

Hello and welcome! This chapter is the foundation of everything we do in Information Technology. Don't worry if some terms sound complicated—we're going to break down the entire IT system, piece by piece, so it makes perfect sense.

By the end of these notes, you’ll understand the essential building blocks—the hardware, the software, and the data—that make your phone, your laptop, and the ATM machine work every single day. Let's get started!

1. Understanding What an IT System Is

An IT System is essentially a combination of components working together to collect, process, store, and disseminate (spread) information. Think of it like a human body—many different parts (organs) have to cooperate for you to function successfully.

The Five Key Components of Every IT System

While we often focus on the computers, a complete IT system requires more than just machines. It needs these five parts to function:

  • 1. Hardware: The physical components you can touch (e.g., keyboard, screen, CPU).
  • 2. Software: The instructions and programs that tell the hardware what to do (e.g., Windows, Microsoft Word).
  • 3. Data: The raw facts and figures the system needs to process (e.g., a student's name, test score).
  • 4. Procedures: The rules and steps users must follow (e.g., the steps to log into an account).
  • 5. People: The users, operators, programmers, and managers who interact with and maintain the system.

Quick Takeaway: An IT system is useless without all five components working together!

2. The Hardware Foundation: The IPO Cycle

All hardware works around a central process known as the Input-Process-Output (IPO) Cycle. This is the simplest way to understand how a computer does its job.

2.1. Input Devices

Input is the first step, where raw data is gathered and converted into a digital format the computer can understand.

  • Function: To accept data from the outside world.
  • Examples: Keyboard, Mouse, Scanner, Microphone, Touchscreen, Web camera.
2.2. Processing (The Central Brain)

The core of the system is the Central Processing Unit (CPU). This is the "brain" that carries out all the instructions given by the software.

  • Analogy: If the input is reading the ingredients (data) in a cookbook, the CPU is the chef carefully following the instructions.
  • Key Functions of the CPU:
    • Control Unit (CU): Manages and coordinates all components.
    • Arithmetic Logic Unit (ALU): Performs all calculations and logical comparisons (e.g., Is 5 greater than 3?).
    • Immediate Access Store (IAS) / Registers: Tiny, super-fast memory locations inside the CPU itself.
2.3. Output Devices

Output is the final stage, where the processed information is sent back to the user in a usable format.

  • Function: To present processed information (results).
  • Examples: Monitor (Visual), Printer (Hard copy), Speakers (Audio), Projector.

🔥 Quick Review Box: The IPO Cycle

Input (Raw Data goes in) → Processing (CPU works on it) → Output (Meaningful Information comes out)


3. Storage: Remembering and Working

Every IT system needs memory to run programs and storage to keep files long-term. We categorize memory into two main types: Primary and Secondary.

3.1. Primary Storage (Main Memory)

Primary storage is essential for the CPU to work efficiently. It is fast, expensive, and located close to the processor.

  • 1. Random Access Memory (RAM):
    • Used to temporarily hold the data and programs currently being used.
    • Key Concept: It is Volatile. This means if the power goes off, everything stored in RAM is immediately lost.
    • Analogy: RAM is your messy desk space. You put the books (programs) you are actively reading there.
  • 2. Read Only Memory (ROM):
    • Holds essential instructions that start up the computer (the BIOS or UEFI).
    • Key Concept: It is Non-Volatile. It retains its contents even when the power is off. It can only be read from, not easily written to.
3.2. Secondary Storage (Backing Store)

This storage holds all your files and programs permanently. It is slower and cheaper than RAM but non-volatile.

  • Function: Long-term, permanent storage of data and applications.
  • Non-Volatile: Data is safe even when the computer is shut down.
  • Examples:
    • Hard Disk Drives (HDD): Uses spinning magnetic platters.
    • Solid State Drives (SSD): Uses flash memory (much faster than HDD).
    • Optical media (CDs/DVDs).
    • USB Flash drives.

💡 Memory Trick: To remember the difference between Primary and Secondary:
Primary = Present (What the computer is working on right now).
Secondary = Saved (Where you store things permanently).

4. Software: The Instructions

Software is the set of instructions that tells the hardware what tasks to perform and how to manage resources. Without software, hardware is just useless plastic and metal.

4.1. System Software

System software is essential for the management of the computer system itself. It is the necessary bridge between the user/application and the hardware.

  • 1. Operating System (OS):
    • The most critical piece of system software.
    • Role: Manages hardware resources (CPU time, memory), provides a user interface (GUI), and manages files.
    • Examples: Windows, macOS, Android, iOS.
  • 2. Utility Programs:
    • Small programs that perform maintenance tasks.
    • Examples: Anti-virus software, disk defragmentation tools, file compression tools.
4.2. Application Software

Application software helps the user perform specific, productive tasks. It relies on the System Software (OS) to run.

  • Role: Designed to carry out tasks the user wants to accomplish.
  • Examples:
    • Word Processors (e.g., Microsoft Word)
    • Spreadsheets (e.g., Excel)
    • Database Management Systems (DBMS)
    • Web Browsers (e.g., Chrome, Safari)
    • Video Games

⚠️ Common Mistake: Students often confuse system software and application software. Remember: System software makes the computer run; Application software makes the user productive.

5. Data vs. Information

The ultimate goal of any IT system is to turn raw, meaningless data into useful, processed information.

5.1. Data (The Input)

Data consists of raw facts, figures, and symbols that have no meaning on their own.

  • Examples: 25, £450, 01/01/2023, Red.
5.2. Information (The Output)

Information is data that has been collected, processed, organized, and structured in a way that gives it context and meaning.

  • Example: If the data (25, £450, 01/01/2023) is processed, it becomes information: "On 01/01/2023, 25 units of item X were sold for a total revenue of £450."

Did You Know? For information to be truly useful, it must be A.C.C.U.R.A.T.E. (Accurate, Complete, Cost-effective, Understandable, Relevant, Accessible, Timely, and Easy to use).

Chapter Summary: You’ve Mastered the Components!

That's a lot of essential knowledge! You now understand that an IT system is a complex, integrated network where hardware acts on software instructions to transform data into valuable information. Keep reviewing the IPO cycle and the difference between primary and secondary storage—these are the building blocks for every IT concept you’ll encounter!