3.4 Computer Systems (hardware, storage)

Question 1

4 types of memory in a computer

Answer 1

Random access memory: volatile from hard drive
Read only memory: non volatile
Cache: fast access, close to CPU volatile
Register: fast access memory, in CPU used in fetch execute cycle

Question 2

Cloud storage

Answer 2

Data in remote location
Need internet, secondary

Question 3

Ad of cloud storage

Answer 3

• secure data even if physical damage of computer
• can be accessed anytime anywhere
• affordable, no need to invest in employees IRL
• can collaborate with other users just need internet

Question 4

Disadvantage of cloud storage 5

Answer 4

• need reliable internet to access
• download + upload speed affected by internet
• user don’t have full control over their data
• data security privacy issues
• host company may suffer security breach

Question 5

Primary v secondary memory

Answer 5

Pri: main memory in computer, volatile, directly accessible by CPU
Sec: permanent store, external device, non volatile, CPU cannot access

Question 6

Define system software + eg

Answer 6

Software that manages operation of computer

Operating system
System utility ( encryption, compression, anti virus)

Question 7

Application software define + eg

Answer 7

Perform tasks for user, separate from computer system

Word processor, movie making, spreadsheet, presentation software - generic

Question 8

4 types of application software

Answer 8

Generic
Proprietary: MS word, Adobe photoshop
Off the shelf: accessible by public
Bespoke/custom: made for specific client

Question 9

Operating system function

Answer 9

Virtual machine
User interface
Memory, input output device management
File security management

Question 10

High vs low level languages

Answer 10

Eng style commands in high

Assembly Lang Uses mnemonic codes / machine code in binary

Ultimately they all have to translate into machine code

Question 11

Three types of generator

Answer 11

Interpreter(line by line) and compiler(all at once): high Lang to machine code
Assembler: assembly Lang to machine code

Question 12

Why is high level language preferred

Answer 12

Closer to human language
Programmer writes easier

Question 13

Ad and disad of high level Lang

Answer 13

Easier to read write cause Eng,ish style commands
Portable

Must be translated to machine code

Question 14

Ads and disad of low level Lang

Answer 14

Control embedded systems

Must use instruction set by processor
Require close attention to detail

Question 15

Embedded system vs not

Answer 15

Pre defined tasks, specific requirements
Often includes interface to task specific hardware , with own RAM/ROM
Non em has many more functions less limits

Question 16

Embedded system costs

Answer 16

Low cost
Slower processor but simplified
Low power consumption for low cost

Question 17

Uses of embedded system 3

Answer 17

Modern car
Digital alarm clock, watch, microwave oven, refrigerator, TV, central heating system, burglar alarm

Question 18

Critical embedded systems

Answer 18

In aeroplanes, mission-critical system made sure to work if anything happens, FAIL SAFE systems built intakes over the main when needed

Question 19

Optical discs define
Ads disad

Answer 19

Stores data digitally
Uses laser beams

Light, portable cheap, reliable
Fragile, easily damaged, storage limited, needs drive to read data

Question 20

Magnetic disks / HDD - description +
Pros and cons

Answer 20

Retrieve info by rotating disks on reading head

High capacity, cheap, reliable, widely available
Heavy, not portable, moving parts may fail due to motors, not easily repaired

Question 21

Secondary storages 4

Answer 21

Optical discs
Magnetic hard drive
Cloud storage
SSD

Question 22

SSD Solid state drive
Ad disad

Answer 22

Persistent store bits as electrical charge

Small compact portable, high capacity, reliable
Expensive, short life span

Question 23

How is data stored on magnetic hard disk

Answer 23

binary data is represented by tiny magnetised regions
read/write head moves while disk spins round
a whole sector is read in one go

Question 24

how does clock speed affect CPU performance

Answer 24

more pulses a second then more fetch-execute cycles
higher clock speed = more instructions can start per second

Question 25

how does number of cores affect CPU performance

Answer 25

more cores = more instructions processed/executed in parallel simultaneously

Question 26

how does cache size affect CPU performance?

Answer 26

data take less time to transfer to the processor from cache as it locates close to processor
more instructions help - CPU can access frequently needed instructions

Question 27

differences between RAM and secondary storage?

Answer 27

RAM is volatile
RAM usually has less storage capacity

Question 28

how does an optical disk read

Answer 28

disk rotates at high speed
laser head moves across disk and reads pits that reflect light and stores binary values

Question 29

embedded systems vs non embedded

Answer 29

embedded has specific purpose, non embedded is general purpose
embedded are usually built into specific devices while non are not
embedded usually have less storage and processing power

Question 30

what is a computer system

Answer 30

combination of hardware and software