Hardware and software
A computer system is built from two complementary halves: hardware and software. They work together — software gives instructions; hardware executes them.
Hardware
Hardware is the physical, tangible part of a computer. You can touch it.
Examples:
- CPU, RAM, motherboard, hard drive, SSD.
- Input devices: keyboard, mouse, touchscreen, microphone, scanner.
- Output devices: monitor, speaker, printer.
- Networking: router, network card, modem.
Hardware is fixed at manufacture (or upgradable as a physical swap). It can fail mechanically.
Software
Software is the set of programs and data that tell the hardware what to do. Intangible — instructions stored as binary.
Examples:
- Operating system (Windows, macOS, Linux, Android, iOS).
- Applications (browser, word processor, games).
- Utilities (antivirus, file compression, defragmenter).
- Firmware (low-level software permanently stored on a device).
Software is flexible — can be updated, replaced, or moved between devices.
How they relate
Hardware without software is inert — a CPU is a heap of silicon until instructions run on it. Software without hardware is just files — a Word document doesn't open itself.
The operating system is the bridge. It translates application instructions into hardware operations and manages shared resources.
Embedded systems
An embedded system is a computer system built into a larger device to perform a dedicated function. Unlike a general-purpose computer, it usually does one job for the device's lifetime.
Examples:
- Washing machine controller — manages water, motor, timing.
- Microwave oven — runs the timer and power level.
- Car engine management — controls fuel injection, emissions.
- Smart thermostat — reads temperature, controls boiler.
- Pacemaker — monitors and paces the heart.
- Smart watch — counts steps, displays notifications.
Characteristics
- Dedicated function — single purpose, not user-customised.
- Low power — often battery operated.
- Real-time — responds to inputs within strict deadlines.
- Compact firmware — software stored in ROM, rarely updated.
- Cheap to produce in volume — built into millions of devices.
Embedded vs general-purpose
| Property | Embedded system | General-purpose computer |
|---|---|---|
| Purpose | Single dedicated task | Many user-installed apps |
| Hardware | Minimal, optimised | Powerful, expandable |
| Software | Firmware in ROM, rarely changed | OS + many apps, frequent updates |
| User interface | Often none, or simple buttons | Keyboard, mouse, touch |
| Cost | Low per unit | Higher per unit |
✦Worked example— Worked example — identify the parts
A smart fridge:
- Hardware: the fridge itself, motor, thermostat, screen, microcontroller.
- Software: firmware controlling temperature; app showing inventory.
- Embedded system: the microcontroller running the firmware that monitors and adjusts temperature.
⚠Common mistakes— Pitfalls
- Calling firmware "hardware". It's still software — instructions in non-volatile memory.
- Treating an embedded system as a separate product. It's a component inside a larger device.
- Confusing OS with applications. Both are software; OS sits between hardware and apps.
- Saying smartphones are "embedded". Modern smartphones run general-purpose OSes — not embedded.
- Listing peripherals as "the computer". Hardware = everything physical, including peripherals.
Why distinguish?
Understanding hardware vs software helps when:
- Diagnosing problems. Crackling speakers? Hardware (cable) or software (driver)? Different fixes.
- Designing systems. Cost trade-offs — better CPU vs more efficient algorithm.
- Securing systems. Firmware updates patch vulnerabilities baked into the hardware-driving software.
➜Try this— Quick check
For each, classify as hardware (H), software (S) or embedded system (E):
- A printer driver: S.
- A printer: H (and contains an E — its internal controller).
- Microsoft Word: S.
- A USB cable: H.
- A smart thermostat's controller: E.
- A graphics card's GPU: H (and firmware = S runs on it).
AI-generated · claude-opus-4-7 · v3-deep-computer-science