Internal Computer Hardware Notes

The CPU (central processing unit) is the brains of the device: the core of the computer’s architecture.
It carries out the commands sent to it by software and returns results for actions to be taken.
History: the earliest CPUs were large circuit boards with limited functionality; today a CPU is generally on one chip and can perform a large variety of functions.
Key manufacturers for personal computers: Intel and Advanced Micro Devices (AMD).
The speed/clock time of a CPU is measured in hertz.
Hertz definition: $1\,\text{Hz} = 1\,\text{cycle/second}$
Modern CPUs may contain multiple processors on a single chip: dual-core (two processors) or quad-core (four processors).
Higher clock speed and multi-core designs increase processing power by enabling more instructions to be executed in parallel.
Term to know: Central processing unit, CPU.
Overview of function: performs computations and logic operations requested by application software and returns results to be acted upon.
Historical contrast: early CPUs were large circuit boards; current CPUs are typically on one silicon chip.

The motherboard is the main circuit board of the computer.
Key components that connect to the motherboard: CPU, RAM, hard disk, integrated graphics card, sound card (if not embedded in the motherboard).
Form factors vary (shapes and sizes) to match how compact or expandable the computer is designed to be.
Modern motherboards often include many integrated components (video and sound processing) that used to require separate parts.
The motherboard provides much of the bus of the computer.
Term to know: Motherboard.
Bus definition: the electrical connection between different computer components.
Importance of the bus: the bus speed is a major determinant of the computer's speed.
The overall speed depends on two factors:
- How fast the bus can transfer data (bus speed).
- The number of data bits that can be moved at one time (bus width).
Formula: $\text{Bandwidth} = f \cdot b$ where
- $f$ = bus frequency (cycles per second),
- $b$ = data width (bits per cycle).
Term to know: Motherboard.

When a computer starts up, it loads information from the hard disk into working memory (RAM).
RAM (Random Access Memory) is the working memory that can transfer data much faster than the hard disk.
Any program you are running is loaded into RAM for processing.
Minimal RAM is required for effective computer operation; more RAM generally allows the computer to run faster.
RAM is volatile: it stores data only while powered; when the computer is turned off, data in RAM is lost.
ROM (Read-Only Memory) is a form of memory where data stored can only be read and typically cannot be changed.
ROM is used during the boot sequence to initialize the operating system.
Terms to know: RAM (Random Access Memory) and ROM (Read-Only Memory).

RAM is used as working memory, but long-term data storage requires other devices.
Historically, hard disk drives (HDDs) were the primary long-term storage devices.
HDD description: stores data on a stack of spinning disks coated with magnetic material inside a hard metal case; data is read and written by a moving read/write head.
HDDs are called hard disks to distinguish from earlier floppy disks (which were flexible and removable).
Solid-state drives (SSDs) have become increasingly popular for long-term storage.
SSD description: no moving parts; store data on flash memory chips.
Benefits of SSDs: faster, more reliable, more durable than HDDs.
Trade-offs: SSDs are typically more expensive per gigabyte than HDDs.
Modern personal computers often use SSDs for the operating system and frequently accessed data, while HDDs are still used for larger, less frequently accessed files.
Term to know: Hard disk.

Metaphor: CPU as the brain, RAM as the desk workspace where active tasks are handled, and the bus as the road network that moves data between components.
Practical implications:
- Upgrading RAM can improve multitasking and overall speed for active applications.
- SSDs improve boot times and responsiveness for frequently used data, at a higher cost per GB compared to HDDs.
- The bus bandwidth and data width fundamentally limit how fast data can be moved between CPU, memory, and storage, influencing real-world performance.
- RAM is volatile and loses data when power is off, while ROM provides non-volatile instructions essential for booting.
- Choosing storage involves balancing speed, durability, and cost: SSDs for speed and reliability; HDDs for large-capacity, cost-efficient storage.

CPU: Central Processing Unit – the brains that executes software instructions.
Motherboard: The main circuit board that connects CPU, memory, storage, and peripherals.
RAM: Random Access Memory – volatile, fast working memory used during processing.
ROM: Read-Only Memory – non-volatile, read-only storage used for booting firmware.
HDD: Hard Disk Drive – traditional long-term storage with spinning magnetic disks.
SSD: Solid-State Drive – fast, durable long-term storage using flash memory.
Bus: Electrical pathway that connects components; its speed and width affect overall system performance.

Computing devices consist of tangible hardware: CPU, motherboard, RAM, ROM, and storage (HDD/SSD).
CPU is the core processor, performing computations and logic; clock speed is in Hz, with multi-core designs (dual-core, quad-core) increasing processing capabilities.
The motherboard connects all major components and includes the data bus that determines speed via bandwidth ~ f × b.
RAM provides fast, volatile working memory, loaded with programs at runtime; ROM provides non-volatile firmware for booting.
Storage devices provide long-term data storage: HDDs use magnetic disks with moving read/write heads; SSDs use flash memory with no moving parts, offering speed and durability but at higher cost per GB.
Understanding these components and their interactions helps explain computer performance, upgrade decisions, and real-world trade-offs between speed, capacity, reliability, and cost.