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Flashcards in 2. Hardware Deck (94)
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1

What does CPU stand for?

Central Processing Unit

2

What does the CPU do?

The hardware that executes programs and manages the rest of the hardware.

3

What are the two main parts of the CPU?

Control Unit - Sends electrical signals to components to control them
ALU - Carries out all the logic and calculations

4

What does ALU stand for?

Arithmetic Logic Unit

5

What things does the CPU need to access?

• Main Memory (RAM)
• Storage devices (Hard disk)
• Input/Output Devices

6

How does the CPU access the things it needs to access?

A system of Buses (wires).

7

What is measured in Ghz?

The amount of instructions that can be carried out per second. (Clock speed)

8

How many calculations per second is 1 Ghz?

1 billion

9

What is a multi-core processor?

One component where two or more CPUs (processors) or 'cores' work together to improve the clock speed.

10

What is cache memory?

Memory close to the core processor with very rapid response. It is used to store instructions before they are executed and temporary data.

11

What is architecture?

How large the gap between transistors is and how many transistors are on a chip.

12

What is memory?

How computers store data and programs.

13

What is RAM?

• 'Main Memory'
• Loads programs and data before running
• Storing generated data before they are stored permanently
• Allows CPU to access data from hard disk
• Volatile -> Loses content when power is turned off

14

What is ROM?

• Holds programs that start up the computer (boot up programs) and programs that have information about the hardware
• Non-Volatile -> 'Remembers' state
• Cannot easily be overwritten

15

What are the main differences between RAM and ROM?

RAM
• Loses its data when computer is switched off
• Temporary storage that is constantly being written to and read from
ROM
• Retains its data even when computer is switched off
• 'Read only' and cannot easily be changed by the program or user

16

What does RAM stand for?

Random Access Memory

17

What does ROM stand for?

Read Only Memory

18

What is virtual memory?

When there is not enough space on RAM, an area of the hard disk is used for temporary memory. This is, however, much slower than RAM.

19

What are some examples of magnetic devices?

• Tape Drive / Digital Audio Tape
• Hard Disk Drive
• Floppy Disk Drive / Disk

20

How do magnetic devices work?

By setting an area of magnetic coated material to NS or EW setting. This can then be scanned by a read/write head.

21

What are some examples of optical devices?

• CD - Rom, CD - R, CD - RW
• DVD - Rom, DVD - R/RW/RAM
• Blu-Ray
• HD-DVD

22

How do optical devices work?

They are read using light - usually laser light (lighter and darker areas are detected). Commercially, troughs are cut into the disk surface. At home, colour change is used.

23

What are some examples of solid state technology?

• Solid State Hard Disc
• Memory Stick (USB)
• Flash Memory (camera type)

24

How does solid state technology work?

There are no moving parts (solid state). Data is stored by applying a voltage to a grid of transistors and enabling or disabling current. NAND gates are used.

25

Why are magnetic drives not appropriate for portable devices?

Moving Parts
Slower data transfer times
Less robust
Larger in size
Uses more power than a solid state

26

What are buses?

The circuits/internal wiring of that connect the processor and main memory.

27

Remember to look at the diagram for how the CPU moves around instructions.

Pg 9 of textbook

28

Describe the fetch-execute cycle.

• Instruction fetched from main memory
• Control unit decodes instruction
• ALU executes instruction
(There may be storage in main memory after this)

29

What is the unit for clock speed?

Gigahertz (GHz)

30

What is clock speed?

The number of cycles per second that a system is capable of.