Computer System Components

Main Components of a Computer System

• Hardware consists of the physical components that make up a computer.
• Examples of hardware include the CPU, memory, main board, monitor, keyboard, mouse, and disk drives.
• Software includes the programs and data utilized by a computer.

Types of Software

• Application software allows users to perform various tasks like word processing, sending e-mail, managing databases, and keeping accounts.
• System software manages hardware, executes application programs, and manages files and data; examples include operating systems and language compilers.

Hardware - Processor

• The Central Processing Unit (CPU) is the "heart" of a computer.
• The CPU performs all the processing tasks for the computer.
• Processing speed is generally measured by the CPU's speed, indicated in GHz (e.g., 3.5GHz).

CPU Components

• Arithmetic Logic Unit (ALU) performs arithmetic and logical operations.
• Control Unit decodes instructions and sets up the ALU with data from memory (RAM/ROM).
• Registers are small, fast memory within the CPU.
• Registers temporarily hold the instruction and data to be processed by the ALU and are accessible by the ALU.

Processor Function

• The processor executes instructions on data using a Fetch-Execute cycle.
• CPUs follow the Fetch-Execute cycle.
• The Fetch-Execute cycle steps are: Fetch, Decode, Read Memory, Execute Instruction.
• Instructions inform the CPU what to do and may require loading data from memory, depending on the architecture and instruction.

Hardware - Memory

• Memory stores programs and data, encoded as binary numbers.

ROM: Read Only Memory

• ROM stores programs called firmware, which starts the computer with default settings.
• ROM provides permanent storage in the computer.

RAM: Random Access Memory

• RAM holds the programs and data currently running.
• The computer loses RAM data when it's turned off.
• The CPU can directly access information stored in RAM.
• Programs can alter the contents of RAM.

Hardware - Secondary Storage

• Secondary storage media provide permanent storage for data and programs.
• The types of secondary storage media: magnetic disks/tapes (HDD), Solid State Drives (SSD, USB flash drives), and optical discs (CD, DVD, BluRay).

Types of Secondary Storage

• Optical media are discs covered with a material where a laser burns holes to store data; examples include DVDs, CDs, and BluRay discs.
• Optical media are convenient to carry and safeguard stored data because is not easily deleted.
• Magnetic media use magnetic materials where data is stored as magnetized (1) or demagnetized (0) spots; examples include hard disks and backup tapes.
• Magnetic media feature larger storage capacity and faster access to data
• SSD (Solid State Drive) is a newer and more expensive storage technology, offering faster data access than magnetic media.
• Examples include SSD disks and USB flash drives.

Data Representation

• All data is represented as binary numbers because binary digits match electric signals.
• The ASCII scheme is the most common method to encode characters of data into binary numbers.
• The basic ASCII system uses 7 bits to represent a character.
• Extended ASCII uses 8 bits to represent a character.