3.1.8 Computer Structure

Question 1

what is volatile memory?

Answer 1

computer memory the requires a power supply in order to maintain stored data
the moment that the power is turned off the information is lost.

Question 2

give an example of volatile memory

Answer 2

RAM (random access memory)

Question 3

what is non-volatile memory?

Answer 3

computer memory that retains its information whether the power being supplied to it is turned off or on

Question 4

give an example of non-volatile memory

Answer 4

read only memory (ROM) and flash memory, as well as most types of magnetic hard disks and optical disks.

Question 5

what is ROM?

Answer 5

(read only memory)

non-volatile, the data is pre-installed and cannot be changed

Question 6

what is RAM?

Answer 6

(random access memory) - volatile
When a program is opened, it get loaded from the hard drive into the RAM, because reading data from RAM is much quicker, making the program’s use quicker.

Question 7

Why is it important for computers to have a sufficient amount of RAM?

Answer 7

A large amount of RAM enables more instructions to be loaded from the secondary storage into RAM, so they can be executed by the processor.

Question 8

what is Cache Memory?

Answer 8

• memory closest to the CPU.
• stores recently used data that can be accessed quickly at a later time
• larger amount of data means more cache-hits likely (CPU finds stored data), so processes will operate faster
• very expensive so is limited in capacity

Question 9

Explain why having cache memory can improve the performance of the central processing unit (CPU)

Answer 9

Frequently used data/instructions are stored in the cache
Meaning they don’t have to be fetched from main memory.
Therefore data/instructions stored in the cache memory can be accessed faster

Question 10

what is virtual memory?

Answer 10

• memory management procedure used when RAM is insufficient. stored temporarily on the hard drive (extends RAM capacity)
• much slower than RAM as it takes up more processing power to move the data around.

Question 11

what is a CPU?

Answer 11

Central Processing unit

processes data and undertakes instructions given by applications and inputs

Question 12

the CPU undertakes instructions it receives from programs in what is called …

Answer 12

a cycle, measured in Hertz (Hz)

Question 13

how is the speed of a CPU measured?

Answer 13

by how many cycles it can perform in a second

(clock speed)

Question 14

what instructions does a CPU’s control unit perform?

Answer 14

Fetch, Decode and Execute instructions then Store results.

Question 15

factors improving performance of a CPU {5}

Answer 15

• the cache size
• the type of cache memory
• the number of cores/processors
• the processing clock speed
• the bus width

Question 16

what is the clock speed and how does it affect the CPU’s performance?

Answer 16

• Speed at which the a microprocessor (meaning contained on one chip) executes instructions
• A higher clock speed means a process will be completed quicker
• However increased clock speed means increased heat produced and more power consumed

Question 17

how does the number of cores affect the CPU’s performance?

Answer 17

[multiple CPU cores on a single chip are called multi-core processors]
multiple cores can run multiple instructions at any given time, so they’re effective when the user is multitasking.
However, software must specifically written to cater for multiple cores

Question 18

what is a graphics card?

Answer 18

contain a processor like the CPU and can be used to process the graphic portion of the processing load.

Question 19

Developments in hardware have made smart phones possible to include: {4}

Answer 19

• More power efficient processors
• Smaller form memory
• Solid state memory
• Affordable touch screens

Question 20

what is the purpose of a Motherboard?

Answer 20

links the CPU to the memory and other hardware.

Question 21

what is (high) reliability?

Answer 21

when a computer system can be depended on to work almost all of the time

Question 22

what is robustness?

Answer 22

the ability of a computer system to cope with execution errors

Question 23

why is high reliability and robustness important?

Answer 23

mean that the computer system can be depended on at all times without any chance of failure

Question 24

what would happen if a system wasn’t reliable or robust?

Answer 24

the user may not be able to use the program when required, which, depending on the situation, could have severe consequences.

Question 25

how can computer systems be made reliable?

Answer 25

duplication of the whole system so that if there is an error, there is always a backup to replace it in case it stops working.

Question 26

what is a computer system?

Answer 26

a combination of hardware and software

Question 27

what is secondary storage?

Answer 27

non-volatile memory that is used to store large amount of data permanently.

Question 28

examples of secondary storage {3}

Answer 28

``` Flash memory > Solid State Memory > USB Memory sticks Optical media > CDs > DVDs Magnetic media > Hard disk drives > Floppy disks ```

Question 29

how does Optical Media work? {6 steps}

Answer 29

- Digital optical discs store binary data as pits and lands on the disc's surface - Bits are encoded as transitions between lands and pits. - An infrared laser is beamed through the CD's material to read the data - The light that bounces off the mirror-like reflective backing is then measured. - An opto-electric sensor can read the stamped pattern by detecting fluctuations in the reflected beam as the laser scans the groove. - - These measurements can then be translated back into binary

Question 30

how does Magnetic Media work? {for magnetic tape and discs}

Answer 30

- Data is stored as tiny magnetised dots. - These dots are created, read and erased using magnetic fields created by tiny electromagnets. In the case of magnetic tape the dots are arranged along the length of a long plastic strip which has been coated with a magnetisable layer In the case of magnetic discs (e.g. floppy disc or hard-drive), the dots are arranged in circles on the surface of as disc that has a magnetisable coating.

Question 31

how does Solid State work? {4 steps} - no moving parts (solid)

Answer 31

- A SSD (solid state drive) uses microscopic electronic switches to store data. - Millions of transistors are either on or off and remain so as long as electricity is applied to the system. - SSDs use switches called floating gate transistors. These create a special cage that traps the electron flow within it. - This effect continues whether there is electricity in the system or not, and so storage remains when the power is removed.

Question 32

Advantages of Solid state media over Magnetic Media {4}

Answer 32

- Speed of read access is higher in solid state drives because data can often be read more quickly - Solid state media can be more compact than magnetic media which enables better portability - Magnetic media has mechanical parts so it's unsuitable for mobile use because the mechanical parts are less robust during movement. - Solid state battery will last longer as it uses less power

Question 33

what does VGA mean?

Answer 33

video graphics array

Question 34

why is bus speed in a motherboard important?

Answer 34

controls how much data the motherboard bus can handle at any one time. more data = faster system

Question 35

why are computer system are essential in modern society?

Answer 35

- They allow people to contact and work with those all around the world - They allow people to access their data securely from anywhere - They improve quality of life, e.g. those without limbs can have then replaced with bionic - They help save lives, e.g. emergency response teams can coordinate rescues quicker