OS: Computer System Architecture

Computer Hardware

it refers to the physical components that make up

a computer system. these components work

together to process, store and communicate data.

Computer Software

It is a collection of programs, instructions, and

data that enable a computer to perform specific

tasks.

Input, Output, Processing, and Storage Devices

Types of Hardware Devices

Operating System

a SOFTWARE that MANAGES and

CONTROLS the hardware, allowing programs and users to interact with the machine.

Central Processing Unit

It acts as the active brain of the computer system that is responsible for executing and managing sequence of instructions called programs directed by the operating system. Just like our brain, it simultaneously regulates all of the internal function inside the computer system.

Parts of the CPU: Control Unit

It directs the operation of the CPU and coordinates the activities of other components, such as memory and input/output devices.

Parts of the CPU: Arithmetic Logic Unit

The component of the CPU that performs arithmetic and logical operations, allowing the execution of mathematical calculations and decision-making processes.

Parts of the CPU: Registers

It is a small and fast storage within the CPU that temporarily holds data, instructions, or addresses being used by the processor

Parts of the CPU: Cache Memory

It is a high-speed memory within the CPU that stores frequently used data and instructions to reduce access time.

Parts of the CPU: Clock

It synchronizes the operations of the CPU by generating a steady pulse of electrical signals.

Parts of the CPU: I/O Interface

It manages communication between the CPU and external devices.

Vonn Neumann Model

Fetch - Decode - Execute Cycle

Memory

is the faculty of the brain (CPU) in which data and information is encoded, stored, and retrieved when needed.

Primary Memory

is the main storage area in a computer system, where data is stored temporarily for quick access by the CPU during processing.

• Volatile, Temporarily stores data and instructions, Much Faster, Accessed by CPU

Secondary Memory

• Non-volatile

• Long Term Storage

• Much Slower

• Accessed thru I/O Operations

Random Access Memory (RAM)

Is the main working memory of a computer. It temporarily stores data and instructions that the CPU is currently processing.

Dynamic Random Access Memory (DRAM)

• Must be continuously refreshed

• Consume more power

• Requires less space

• Cost less

• Hold more data

• Typically uses for main memory

Static Random Access Memory (SRAM)

• does not required

  refreshing.

• consume less power

• requires more space

• expensive

• hold less data

• typically uses for

  cache memory.

L1 Cache

Located directly on the CPU, the fastest

and smallest cache.

L2 Cache

Slightly slower than L1 but larger and typically located on or near the CPU.

L3 Cache

Larger and slower than L1 and L2,

often shared between CPU cores.

Types of Registers: Program Counter

Holds the memory address of the next instruction to be executed.

Types of Registers: Accumulator

The accumulator typically holds the result of a calculation performed by the Arithmetic Logic Unit (ALU).

Instruction Register

After the instruction is fetched from memory, it is loaded into the IR for decoding and execution.

Memory Address Register

Holds the memory address of the location being accessed for reading or writing.

Memory Buffer Register

Holds the data to be transferred to/from memory.

Status Registers/ Flag Registers

Used by the control unit to make decisions based on the results of previous operations.

HARD DISK DRIVE

it is a magnetic storage devices that use spinning disks (platters) to read and write data. It can stored several hundreds of gigabytes to multiple terabytes.

SOLID STATE DRIVE

It uses flash memory to store data, which provides faster access speeds than HDDs. It is more durable than HDD’s because it has no moving parts.

OPTICAL DISC

It uses lasers to read and write data to disks like CDs, DVDs, or Blu-ray discs. It is commonly used in media distribution.

USB FLASH DRIVE

It is a portable, solid-state storage devices that use flash memory. they uses USB ports for transferring and receiving files between devices.

NETWORKED ATTACHED STORAGE

it is a file-level data storage device connected to a network, allowing multiple users and devices to access and share data over the network.

VIRTUAL MEMORY

It is considered a part of secondary memory. It is a memory management technique that uses secondary storage, such as a hard drive or SSD, to extend the capabilities of primary memory (RAM).