Module 2: Computer Hardware and OS

Introduction to Computer Hardware

Computer hardware refers to the physical components that make up a computer system. These components work together to process, store, and transmit data, enabling the computer to function.

In this module, we'll explore the major hardware components, their roles, and how they interact with the operating system to create a functioning computer system.

Core Hardware Components

Central Processing Unit (CPU)

The CPU is the brain of the computer, responsible for executing instructions and performing calculations. Modern CPUs contain multiple cores, allowing for parallel execution of tasks.

• Instruction Cycle: Fetch, decode, execute, store
• CPU Cache: L1, L2, and L3 caches provide fast access to frequently used data
• Clock Speed: Measured in GHz, indicates how many cycles per second
• Architecture: CISC vs. RISC design approaches

Memory (RAM)

Random Access Memory provides temporary, high-speed storage for data that the CPU needs to access quickly. RAM is volatile, meaning its contents are lost when power is turned off.

• Types: DDR4, DDR5, etc.
• Capacity: Measured in gigabytes (GB)
• Access Time: Typically measured in nanoseconds
• Role: Stores currently running programs and their working data

Storage Devices

These provide persistent storage for the operating system, applications, and user data.

• Hard Disk Drives (HDD): Magnetic storage, slower but more affordable for large capacities
• Solid State Drives (SSD): Flash memory-based storage, faster but more expensive
• NVMe: Interface protocol designed to accelerate the transfer of data between SSDs and a computer's CPU
• Access Times: Milliseconds (HDD) vs. microseconds (SSD)

Motherboard

The main circuit board that connects all components together, providing pathways for data transfer.

• Chipset: Controls communication between CPU, memory, and peripherals
• Bus: Pathway for data transfer between components
• Form Factors: ATX, Micro-ATX, Mini-ITX, etc.
• Expansion Slots: PCIe slots for graphics cards, network cards, etc.

Operating System Fundamentals

The operating system (OS) is system software that manages computer hardware, software resources, and provides services for computer programs.

Core Functions

• Process Management: Creating, scheduling, and terminating processes
• Memory Management: Allocating and deallocating memory for processes
• File System Management: Organizing and controlling access to files
• Device Management: Controlling input/output operations with peripherals
• Security: Protecting system resources and user data

Process and Thread Management

Processes are instances of executing programs, while threads are the units of execution within a process.

• Process States: New, Ready, Running, Waiting, Terminated
• Context Switching: Saving and restoring process state when switching between processes
• Scheduling Algorithms: First-Come-First-Served, Round Robin, Priority-based, etc.
• Multi-threading: Concurrent execution of multiple threads within a process

Memory Hierarchy

Memory is organized in a hierarchy, with faster but smaller storage at the top and slower but larger storage at the bottom.

• Registers: Fastest memory, inside the CPU
• Caches (L1, L2, L3): Small, fast memory between CPU and RAM
• Main Memory (RAM): Primary working memory
• Secondary Storage: Hard drives, SSDs
• Tertiary Storage: Tape drives, optical media

Understanding this hierarchy is crucial for optimizing software performance.

Hardware-Software Interaction

System Calls

System calls are the interface between user applications and the operating system kernel, allowing applications to request services from the OS.

• Types: Process control, file management, device management, information maintenance, communication
• Implementation: Typically involves a mode switch from user mode to kernel mode
• Examples: open(), read(), write(), fork(), exec()

Virtualization

Virtualization allows multiple operating systems to run on the same physical hardware simultaneously.

• Virtual Machines: Complete abstraction of physical hardware
• Containers: Lightweight virtualization at the OS level
• Hypervisors: Software that creates and runs virtual machines
• Benefits: Resource efficiency, isolation, flexibility

Performance Considerations

Understanding hardware-software interactions helps identify and resolve performance bottlenecks.

• I/O Bottlenecks: Slow disk access, network latency
• CPU Bottlenecks: Compute-intensive operations, inefficient algorithms
• Memory Bottlenecks: Insufficient RAM, excessive paging
• Optimization Techniques: Caching, parallel processing, asynchronous I/O

Resources