0.1.4 Tour of a PC tower

In one line: open the side panel and you’ll see eight things — learn their names once and the rest of this chapter is just zooming in on each.

Do not learn hardware as vocabulary first. Learn it as a room you can point around: board, chip, memory, storage, card, power, cooling, case. Image: Wikimedia Commons, Computer inside (1).jpg.

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A story — IBM’s “weekend project” that ate the world

In 1980, IBM was a mainframe company. The personal-computer market was Apple’s, Commodore’s, Tandy’s. IBM management told a small skunkworks team in Boca Raton, Florida: build us a PC, in one year, using off-the-shelf parts. The team — Don Estridge and twelve engineers — said yes.

To hit the deadline they did something unprecedented for IBM: they bought everything from outside vendors. Intel chips. A scrappy little operating system from a 24-year-old named Bill Gates (DOS). An open architecture so anyone could plug in expansion cards.

The IBM PC shipped August 1981. Within five years, clones — Compaq, Dell, HP — were selling the same architecture for less. The “PC” became a category. Apple stayed proprietary; everyone else converged on the IBM design. The motherboard layout you’d see if you opened a tower today is a direct descendant of that 1981 board.

What’s actually going on

If you unscrew the side panel of a desktop PC, here’s what you’re looking at:

#	Part	What it does
1	Motherboard	The big green/black PCB that everything plugs into — the city’s road network
2	CPU	A square chip in the middle, hidden under a heatsink and fan — the worker
3	RAM	Long thin sticks slotted vertically next to the CPU — the desk
4	Storage	A 2.5” SSD, 3.5” HDD, or a tiny M.2 stick on the motherboard — the filing cabinet
5	GPU	A long, heavy card in the bottom slot, with its own fans — the artist
6	PSU	A box at the top or bottom corner with a fan and many cables — the power station
7	Cooling	Fans, sometimes liquid loops — keeps the heat from melting things
8	Case + I/O panel	The metal box itself, plus the back panel with USB / HDMI / Ethernet / audio jacks

The motherboard is the centrepiece. Everything physically plugs into it: the CPU socket, the RAM slots (usually 2 or 4), the M.2/SATA storage connectors, the PCIe slots (where the GPU lives), and the front-panel headers where the case’s power button and USB ports connect.

Why a hacker cares

Each of these parts has its own attack surface and its own forensic value:

• Motherboard / chipset runs firmware that even the OS can’t see. Compromise this and you have rootkit-level persistence (look up “Equation Group” implants).
• CPU has microcode that can be updated — Intel and AMD push patches for vulnerabilities like Spectre via microcode.
• RAM holds everything in plaintext while running — passwords, keys, decrypted documents. Cold boot attacks chill the RAM with cooling spray and dump it before it forgets.
• Storage retains data even after deletion — data-recovery is a forensic specialty. Encrypted drives need the OS to decrypt them; pull the drive and you mostly just get ciphertext.
• GPU has its own memory and can do general computation — modern crypto-mining malware and some recent exploits use GPUs to hide from CPU-based detection.
• PSU can be backdoored to leak data via power-line patterns (academic work, but real).
• USB ports are an entire attack vector — BadUSB, RubberDucky, malicious “phone chargers.”

In one sketch

   ┌────────────────── PC TOWER (side view) ──────────────────┐
   │                                                          │
   │  ┌─────────┐                          ┌──────────────┐   │
   │  │   PSU   │                          │ Motherboard  │   │
   │  │ ⚡ ▸▸▸ │ ← cables to everything    │  ┌──┐  ┌──┐  │   │
   │  └─────────┘                          │  │CPU│ │RAM│  │   │
   │                                       │  └──┘  └──┘  │   │
   │  ┌─────────┐                          │     │ │GPU│  │   │
   │  │ 💾 SSD  │ ← SATA/M.2 to mobo       │     │ └──┘  │   │
   │  └─────────┘                          └──────┴──────┘   │
   │                                                          │
   │  Fans ◌ ◌ ◌                          [ I/O on back ]    │
   └──────────────────────────────────────────────────────────┘

Reference and image credit

• Computer_inside_(1).jpg — Luke, public domain.

Memory peg

Motherboard, CPU, RAM, Storage, GPU, PSU, Cooling, Case. Eight parts. Every desktop PC ever built since 1981 is just a different arrangement of these.