Smartphone Technology – SS3 Computer Hardware & GSM Repair Lesson Note (Second Term)

A smartphone’s architecture is the plan for how its software talks to its hardware, such as the battery, screen and chip. The operating system (OS) runs everything. The two main systems are Android, made by Google, and iOS, made by Apple. Android is open and used by many companies, while iOS is closed and made only by Apple.

Behavioural objectives

By the end of the lesson, students should be able to:

• explain what an operating system and smartphone architecture are;
• state the difference between open (Android) and closed (iOS) architecture;
• list and describe the four layers of Android;
• list and describe the four layers of iOS;
• compare Android and iOS in customisation, file system, repair difficulty and app source.

What is the operating system of a smartphone?

When you pick up a phone, you see the screen, the buttons and the camera. But inside, there is a “Government” running everything. This is called the Operating System (OS).

Today, there are two main “Governments”: Android (made by Google) and iOS (made by Apple). They both let you make calls and browse the internet, but they are built very differently on the inside. Understanding these differences is the first step to becoming a professional phone technician.

What is architecture in a smartphone?

In building, architecture is the plan for where the walls, doors and roof go. In a smartphone, architecture is the plan for how the software talks to the hardware (the battery, the screen and the chip).

• Android architecture: It is “Open”. This means many different companies (Samsung, Infinix, Tecno) can use the plan and change it to fit their own phones.
• iOS architecture: It is “Closed”. Apple is the only company that makes the software and the hardware. It is like a private house where only the owner has the keys.

What are the layers of Android?

Think of Android like a four-storey building. This is called the “Stack”.

1. The Kernel (the foundation): This is the bottom layer. It talks directly to the hardware. If you plug in a charger, the Kernel tells the battery to start taking in power.
2. Hardware Abstraction Layer (HAL): This layer acts like a translator. It makes sure that the Android software can understand the camera, whether it is made by Sony or Samsung.
3. The Runtime (the engine): This is where apps live and run. Android uses something called “ART” (Android Runtime) to make apps fast.
4. The Application Layer (the roof): This is what you see: the icons, the WhatsApp app and the settings menu.

What are the layers of iOS?

Apple’s system, called the “Cocoa Touch” system, is built for smoothness and security. It also has four main layers:

1. Core OS: The very bottom. It handles the most basic things like memory and security.
2. Core Services: This handles things like your “Files”, “Location” and “Cloud” storage.
3. Media Layer: This is special. It is designed to make videos, photos and music look and sound perfect. Apple puts a lot of power here.
4. Cocoa Touch: This is the top layer. It is designed for your fingers. Every time you “swipe” or “pinch” the screen, this layer makes it feel smooth.

What are the key differences between Android and iOS for the technician?

As a technician, you will notice these differences when you try to fix the phones:

Why does it matter?

• For security: iOS is generally harder to “hack” because the system is closed.
• For choice: Android is better for people who want a phone that fits their specific budget, from ₦50,000 to ₦1 million.
• For performance: Because Apple makes both the chip and the software, iPhones often run very fast even with a smaller battery.

How can you remember the difference between Android and iOS?

Android is like a Public Park. Anyone can enter, and you can move the chairs around. iOS is like a Luxury Hotel. It is very beautiful and safe, but you must follow the manager’s rules, and you cannot move the furniture.

Evaluation

1. Which company makes the Android Operating System?
2. What is the main advantage of a “Closed” architecture like iOS?
3. If a customer wants a phone they can customise heavily, which OS would you recommend?
4. What does the Kernel do in a smartphone?

Assignment

1. List the four layers of Android and the four layers of iOS, and describe what each layer does.
2. Write a short comparison of Android and iOS using the four features in the table: customisation, file system, repair difficulty and app source.