(The adventure of a computer saying “good morning”)
Imagine this…
You press the power button on your computer in the morning. While you’re still rubbing your eyes, the computer goes vroommm and starts working. But all you see is a black screen or maybe the manufacturer’s logo.
Behind the scenes, however, the secret heroes of the computer are stepping onto the stage: BIOS, CMOS, POST, and Shadowing.
This quartet is like the midwife team at the birth of a computer. Without them, the machine would never come to life.
Alright, let’s bring them on stage: 🎤
🧙 BIOS: The Wise Wizard of the Computer
Full form: Basic Input/Output System
Where does it live? On the motherboard, inside the ROM (Read-Only Memory) chip.
What’s its job? When you power on the computer, it initializes the hardware, performs basic checks, and starts up the operating system.
You might think of BIOS as the computer’s brain, but in reality, it’s more like that parent who wakes you up in the morning saying: “Get up, have breakfast, go to school!”
For the computer, BIOS says: “Come on, is the RAM okay? Is the disk awake? Let’s get moving!”
🔍 Technically, it does this:
- Loads the initial hardware settings.
- Checks devices like keyboard, mouse, graphics card, RAM.
- Finds and runs the operating system (from HDD, SSD, CD, USB, etc.).
In short, BIOS is the conductor of the computer’s startup orchestra. 🪄
🪫 CMOS: The Forgetful Planner
Full form: Complementary Metal-Oxide Semiconductor
Where does it live? On the motherboard, a small memory chip that stores BIOS settings.
What’s its job? Stores the date, time, and BIOS configuration.
Think of CMOS as that slightly forgetful aunt who constantly checks her planner: “What day is it today again?” 😅
Your computer’s date, time, and BIOS settings are all kept here.
⚡ But there’s a catch: CMOS needs power to keep this memory alive. That’s why the motherboard has a tiny battery (usually a CR2032). If the battery dies… your computer wakes up in the year 1970 and cheerfully says: “Happy New Year!” 🎉
🕵️ POST: The Computer’s Detective
Full form: Power-On Self Test
What’s its job? To interrogate the hardware when the computer starts.
POST is like the Sherlock Holmes of the startup process. At boot, it inspects every part:
- RAM: “Are you working properly?”
- Keyboard: “Do your keys respond?”
- Graphics card: “Can you show me something on screen?”
If something’s wrong:
- It will print an error message on screen,
- Or, more dramatically, it will start beeping: “beep, beep, beep!”
📌 Note: Each beep code means something different. For example, three short beeps might signal a RAM issue, while a long beep could mean a graphics card failure. Basically, your computer is talking to you in Morse code!
🪞 Shadowing: The Cheating Student
Full form: BIOS Shadowing
What’s its job? Copies the BIOS code from the slow ROM chip into faster RAM.
Shadowing is a bit of a trickster. Normally, BIOS code sits in slow ROM. But to speed things up, the system copies that code into RAM.
Think of it like this:
Your teacher gives you a photocopy of the lecture notes. Instead of digging around in your bag for it every time, you copy the important bits into your notebook so you can find them faster. That’s exactly what Shadowing does.
The result? A faster boot and a smoother startup.
🎭 The Opening Act: A Computer Says Good Morning
If we turned the computer’s startup into a stage play:
- BIOS → “Everyone take your places, we’re starting!”
- CMOS → “It’s October 3, 2025, 09:12 AM. My planner says so.”
- POST → “RAM is fine, graphics card is fine… hmm, the keyboard looks suspicious.”
- Shadowing → “Boss, I copied the codes into RAM. From here on, we’re lightning fast.”
And once the stage is set, the operating system (Windows/Linux/macOS) enters and says:
“Hello user, good morning!” 🌞
🔧 Why Should You Know This?
Because many “computer won’t start” issues come down to these heroes:
- If the date keeps resetting → The CMOS battery is dead.
- If you hear beeping at startup → POST is trying to tell you something.
- If the BIOS screen won’t appear → The BIOS chip may be faulty.
- If startup is super slow → Shadowing might be disabled.
🎬 Curtain Call
That black screen you see at startup is actually a whole theater show happening behind the scenes.
- BIOS = Wizard Gandalf 🧙
- CMOS = Forgetful planner aunt 📒
- POST = Sherlock Holmes 🕵️
- Shadowing = The quick, cheating student 📑
Thanks to them, your computer greets you with a “good morning” every day. And most of the time, we don’t even notice the work they do behind the curtain.
💡 In short:
Those little “beep” sounds and the black screen at startup are nothing more than your invisible backstage crew, working hard for you.
