Computer Science - Unit 2: Hardware

CPU

Central Processing Unit, carries out all of the processing in a computer.

Output Devices

Monitor Printer Speaker

Power Supply

A device that provides power to a computer.

Binary Logic

All computers work in binary and use simple logic circuits to make calculations.

Wireless Network

Any type of computer network that is not connected by cables of any kind.

ALU

Arithmetic and Logic Unit, carries out all of the arithmetic and logical processes.

Central Processing Unit (CPU)

Brain of the computer that performs instructions defined by software

Storage Considerations

Capacity - How much data does it need to hold. Speed - How quickly can data be transferred. Portability - Does it need to be able to move data easily. Durability - Is it easily damaged if transported etc. Reliability - Does it need to be able to be used over and over.

Fetch/Execute Cycle

Fetch: The instruction is fetched from the memory. Decode: The instruction is decoded to find out what processing is needed. Execute: The instruction is then executed, a new instruction is the fetched.

Binary Code

Groupings of 1's and 0's that makes information that a computer can understand.

Hardware Components

Input, Output, Storage, and Processing.

ROM

Non-Volatile, data is retained even after the power is turned off, stores instructions required for the turning on of the computer. It is small, about 1 - 2 MB.

operating system software

Programs that make the computer work. ex: Windows 8, vista, GUI, Linux.

Software

Set of instructions that tells the hardware what to do. It is what guides the hardware and tells it how to accomplish each task.

Magnetic Hard Disk

Stores the operating system, installed programs, and user data. they are fast, reliable, high capacity and low cost.

Hardware

The physical components in a computer system.

RAM

Volatile memory, data is lost when the power is turned off, it can be accessed and changed at any time. It stores programs and data being used by the computer, tends to be large - around 4 GB or more.

Order of bytes from least to greatest

bits, byte, kilobyte, megabyte, gigabyte, terabyte.

Output

device that projects images, gives sound, and basically gives out the info from the computer so the user can obtain it (ex: monitor, printer, projector, speakers)

Input

device used to insert data into a computer or other device (ex: keyboard, mouse, microphone, scanner, voice recognition)

Boot Process

starting up a computer from a halted or powered down condition.

Virtual Memory

A part of the hard drive can be used as an extension to RAM. It is used when the computer doesn't have enough RAM to hold all the data and programs required, although it is much slower.

Flash Memory

A type of ROM that can be re-written. used as a portable medium for storing and transferring data.

Cache Memory

Has access times similar to the CPU but its very expensive, data in use is transferred here to make access to it much faster.

Input Devices

Keyboard Mouse Microphone Camera

Motherboard

Printed circuit board on which the CPU, RAM chips and other electronic circuit elements of a digital computer are frequently located.

RAM

Random Access Memory - temporary place to store material that works quickly. erased when computer turns off. Volatile.

ROM

Read Only Memory- Permanent instructions that cannot be changed. It makes the BIOS function. Checks your OS.

User Friendly

Something anyone can operate

Hard Drive

Storage device that stores digitally encoded data on rapidly rotating rigid disks with magnetic surfaces. The device is either permanently installed within the computer case or can be portable

Computer Architecture

The internal logical structure and organisation of the computer hardware.

Clock Speed

The speed of the Fetch/Execute cycle is determined by the clock chip.

Multiple Processor Cores

Use multiple CPU's Working together, they can all fetch, decode, and execute instructions at the same time. Advantages: more data processed simultaneously Disadvantages: more complex operating systems are required to manage them.

PowerPoint

Used for presentations.

Optical Disk

Used for transferring data files or distributing software. They are low cost, lightweight and portable, and have a good capacity.

Excel

Used mainly for formulas and organizing data.

Word

Used mainly for writing documents.

Secondary Storage

Used to store data when the power is turned off.

Control Unit

Uses electrical signals to control the flow of data within the CPU.

Application Software

ex: Word, Excel, Photoshop, WordPerfect...

Auxiliary Storage Devices

ex: network drive, hard drive, flash drive, google drive.