Component of CPU (Central Processing Unit)

• Controller - Coordinates the other parts of the CPU

• ALU - Does Arithmetic Calculation and Logical operation

• Register - Single fast volatile memory. E.g: the program counter

• Internal Memory - Holds frequently used instructions and results of calculations (also called cache memory)

Main Memory

RAM (Random Access Memory)

• RAM in used to hold running programs and data for them.

ROM (Read Only Memory)

• ROM is permanently store data, e.g: it store BIOS and starts the PC up.

Secondary Storage

HDD (Hard Disc Drive)

• HDDs have a spinning platter

• Have moving read/write heads

• Cheap per GB

• Slow compared to SSD

• Affected by fragmentation

SSD (Sold State Drive)

• No moving parts

• Expensive per GB

• Very fast compared to HDD

• Not affected by fragmentation

• Limit number of read/write cycles

Cloud Storage

• If the storage is free then it is cheaper than physical storage like HDD and SSD

• It might be more expensive if you have to pay it monthly

• Accessible to any device with internet access

• Accessible to anywhere in the world

• Automatically backed up

• Security issue (easier to hack into)

Clock Speed

The speed at which a processor operate is called the clock speed. The faster the clock speed, the faster the computer is able to run the fetch-decode-excute cycle and therefore process more instructions.

The speed of the processor is measured in Hertz (Hz). One clock tick per second would be measured as 1Hz. Therefore p a processor that operate 1,000 clock ticks per second would be 1,000Hz processor, also known as 1kHz processor.

A typical modern day home computer would have a 2.5GHz processor. This means the clock speed of the processor runs at 2,500,000,000 Hz or clock ticks per second.

The clock speed inside the CPU can sometimes be changed. A processor can be set to run faster than its original design. By doing this however, it uses more energy and produce more heat. If the hat is not removed through cooling, the CPU can overheat, which will damage the CPU and shorten its lifespan. This is called overclocking.

Some computers systems, especially mobiles devices, set the clock speed of the CPU lower than its original design. The results in less power consumption, less heat being produced and will therefore increase the battery life of the device. This is called under-clocking.

Motherboard

• Motherboard is where all the components of a PC plug into

Hardware Port

• Hardware port allow peripherals (mice, keyboards and etc) to be connected to the motherboard.

CISC and RISC

CISC (Complex Instruction Set Computer)

• Can process a large number of complex instruction, this allows the processor to understand and carry out complex task with only a few instruction

• CISC is able to process complex instruction, without breaking them into simpler instruction

• Need more power and produce more heat

RISC ( Reduced Instruction Set Computer)

• Can process a limited number of simple instruction, to carry out more complex instruction the problem needs to broke down into a long list of simple instruction.

• Able to process simple instructiom quicker

• Need less power and produce less heat

Cache memory

• A very fast, volatile memory in or on the CPU, used to store frequently instructions used and result of calculations

What is parallel processing

• When a task is split into sub-tasks and two core or more is working on the task same time

Advantages of parallel processing

• Advantages

  • Executes multiple sub-tasks simultaneously

  • Faster than single core

Disadvantages

• Disadvantages

  • Programs need to be specially written for it

  • Some tasks can only be done in a linear manner

What is secondary storage

• A non-volatile stoarge, it tends to be quite large but slow compare to RAM

What is GPU

• GPU stand for Graphic Processing Unit, and it is a processor just to make display in the screen

What is sound card

• A small seperate component just to produce high quality sound

What is embedded system

• A combination of hardware and software to perform a specific task

What is optical storage

• Storage devices that are read by lasers. E.g: DVD, CD and blueray

What is magnetic storage

• Storage devices that store data magnetically. E.g: Hard drive and Tape drive

Describe the 3 type of buses

1. Address bus. When data is saved or loaded from memory, the address at which it is to be stored or loaded from must be sent. The storage address of data always travels along an address bus.

2. Data bus. Data will then need to be moved between several parts of a computer. The path along which data travels is called a data bus.

3. Control bus. The controller uses the control bus to send control signals to different parts of the computer.

The fetch-decode-execute cycle

1. The fetch cycle takes the address required from memory, stores it in the instruction register, and moves the program counter on one so that it points at the next instruction.

2. The control unit checks the instruction in the instruction register.  The instruction is decoded to determine the action that needs to be carried out.

3. The actual actions that happen during the execution cycle depend on the instruction itself.

What is von neumann

• It is the idea of storing a program’s instructions in the same memory as the data. The idea resulted in computers be more easily re-programmed and is the basis for the fetch-decode-execute cycle, fundamental to modern computer processing.

What is flash memory

• A long-life and non-volatile memory widely used in embedded system. The data stored in flash memory can be read and change

What are the disadvantages of ROM compare to flash memory

• In flash memory the data can be changed

The speed of ROM, RAM, Cache memory and Flash memory

1. Cache memory

2. ROM

3. RAM

4. Flash memory

Storage units