IT Theory - Hardware

CPU (Central Processing Unit)

The central component containing two main sections: the CU and the ALU. It is connected to main memory via the address bus, data bus, and control bus

Control Unit (CU)

The section of the CPU that controls the execution of each instruction. It sends read or write signals to memory and specifies the address of the instruction or data to be fetched or stored

Arithmetic Logic Unit (ALU)

The part of the CPU where calculations and logical comparisons take place. Processed data results may be sent back to memory

Accumulator

A specific register within the ALU that stores the result of each instruction execution

Registers

Small storage locations used by the CPU to store the current instruction and its data

Static RAM (SRAM)

The extremely fast, expensive type of RAM used to make registers. It does not contain capacitors, which helps constantly increase its access time

Serial Processing

CPU processes one instruction at a time, using a single core to execute instructions sequentially, one after the other

Parallel Processing

Simultaneously breaking up and running program instruction on multiple microprocessors . The problem is broken into separate parts that execute at the same time

Hyperthreading

Duplicating the registers on the chip, allowing the next instruction to be preloaded while the first is processed, reducing the time required to switch between instructions

Thread (in hyperthreading context)

A process appears to the CPU to execute two sets of instructions simultaneously

Multiprocessing

Having multiple CPUs, called cores, on a single CPU chip. It provides more execution resources and allows programs to run simultaneously

Processor Cache

Storage located on or near the CPU that holds data so future requests can be served faster

Level 1 Cache (L1)

A very small amount of cache built into the internal circuitry of the CPU chip, usually running at the same speed as the CPU's internal speed

Level 2 Cache (L2)

Cache usually located on the CPU chip (but external to the internal circuits); slightly larger than L1 but slightly slower

Level 3 Cache (L3)

Cache sometimes located on the motherboard's virtual board; it is larger and slower than L1 and L2

Latency

The time taken for a component to respond

RAM

Chips attached to dedicated slots on the motherboard that store the programs currently in use and the data associated with them

Synchronous Dynamic RAM (SDRAM)

RAM chips whose refreshing process is synchronised with the CPU clock [5, 6]. Uses a capacitor that loses charge and must be refreshed frequently

Double Data Rate (DDR)

Data is transferred twice as fast as when data was transferred only once every clock pulse

Motherboard

The central printed circuit board that connects components and devices, such as the CPU and RAM, to each other

System Clock (Clock)

A microchip that regulates the timing and speed of all computer functions

Overclocking

The practice of making computer components run at speeds faster than designed by manipulating the frequencies at which the component is set to run

Throughput

The amount of data that can be processed in a certain time

Bandwidth

The theoretical speed of data

Front Side Bus

A physical bus that connected all components on the motherboard, typically connecting the CPU and RAM

Data Bus

Carries the actual instruction or data between the CPU and RAM

Address Bus

Carries the physical address of the instruction or data between the CPU and RAM

Control Bus

Carries the control commands between the CPU and RAM

PCI Express (PCIe)

An external bus where slots are used to connect components like graphics cards and SSDs to the motherboard

SATA (Serial Advanced Technology Attachment)

A bus interface used to connect mass storage devices (HDDs and SSDs)

USB (Universal Serial Bus)

Technology designed to standardise the connection of peripherals to computers, providing both communication and power

NVMe (Non-Volatile Memory Express)

A computer communication bus interface that connects SSDs to the motherboard, allowing them to read/write at much higher speeds than via a SATA connection

M.2 Format

A new interface designed to decrease the size and increase the speed of SSDs, supporting various connection types like SATA 3.0, PCIe, USB 3.0, and NVMe

Secondary Storage

Hardware devices (internal or external) used to store large amounts of data, such as hard disk drives (HDDs) and solid-state drives (SSDs)

Cloud Storage

Remote storage that is accessed using the Internet, rather than a physical device attached to the local computer

Caching (General Concept)

A technique extended to any device or component that uses something faster to temporarily store data, speeding up access time for that component

Disk Cache

A hardware mechanism, usually included as part of the hard disk, that improves the time it takes to read or write to the disk by storing frequently accessed data

Browser Cache

A copy of a website's components (graphics, scripts, cookies) kept on the user's local disk after a website is accessed, allowing the page to load faster on subsequent visits

Web Cache / Proxy Server Cache

A shared store of previously downloaded web pages and images located on a server within an organisation's network. This system reduces overall network traffic by fulfilling subsequent requests internally