Computer Systems

Question 1

What do firewalls do?

Answer 1

Check data packets meet requirements ,
Protects against unauthorised access.
Set rules about which stations on a network can send or receive packets

Question 2

What rules do firewalls take account of?

Answer 2

Sender and receiver IP address, port numbers, protocols

Question 3

What does encryption do?

Answer 3

Protects data during transmission
Scrambles data so if stolen can’t understand
Creates simple key that encrypts data
Keeps simple key secure by combination of public and private keys

Question 4

Public key?

Answer 4

Known by everyone, encrypts data

Question 5

Private key?

Answer 5

Known by recipient, decypts data

Question 6

what is a denial of service(DOS)

Answer 6

Floods website or online service so gets overloaded and stop working for real users

Question 7

4 ways to reduce energy usage

Answer 7

Standby mode,hibernate mode,montior settings , power down settings

Question 8

Standby mode?

Answer 8

Ram contunies to be powered, data temoray stored, power to other components reduced or stopped

Question 9

Hibernate mode?

Answer 9

Ram copied to harddisk, hard disk saves perment copy, all compoments off or very low energy use

Question 10

Monitor Settings?

Answer 10

Reduce brightness, activate effeciency mode and don’t use screen saver

Question 11

Power down settings?

Answer 11

Power down after a period of not using(Monitor,desktop/laptop), settings for indivual components

Question 12

CPU(central processing unit)?

Answer 12

fetch, decode, excute instructions from RAM
Preform arithmatic calculations & logical operations
control, read, write,clock, inturrupt and reset lines(all wires)

Question 13

What parts does the CPU consit of?

Answer 13

Control unit, ALU(ARithmatic and logic unit), registers

Question 14

what does the control unit do?

Answer 14

manages the different lines

Question 15

Clock line?

Answer 15

sends out signal to synochrise fetch&excute cycle

Question 16

Read line?

Answer 16

read data from RAM

Question 17

Write line?

Answer 17

writes data to RAM

Question 18

Reset line

Answer 18

clears all registers

Question 19

Intrrupt lines

Answer 19

handle interruptoions to a process during execution

Question 20

ALU?

Answer 20

preforms all calculations, comparisons on numeric vaules, makes decisions based on logic (AND,OR,NOT)

Question 21

Registers?

Answer 21

temorory storage locations in processor, stores addresses,data,instructions, fast access

Question 22

Types of computer memory

Answer 22

different types with different purposes.
Backing storage,main memory, cache,registers

Question 23

Backing storage?

Answer 23

outside proccessor, stores data permently. e.g. usb memory stick

Question 24

Main memory?

Answer 24

Inside computer, types- RAM(Random access memory), ROM (Read only memory)

Question 25

RAM?

Answer 25

processor reads and writes from RAM, contents lost, holds programs & files when being used, more ram = faster, different locations

Question 26

ROM?

Answer 26

data cannot be changed, contents not lost when turned off, essential data & progams are stored in ROM (e.g. operating system)

Question 27

Cache memory?

Answer 27

fast access, adjacent to processor & main memory, fast access to store data that is needed quickly

Question 28

Register?

Answer 28

storage inside processor, holds data transferred to&from memory, insturctions that are being carried out, addresses of memory locations the processor is accessing.

Question 29

order of different types of memory slowest and biggest to fastest but smallest

Answer 29

Backing storage, RAM, cache, registers

Question 30

Buses?

Answer 30

transfers data from one port to another

Question 31

Data bus?

Answer 31

data transfered to and from main memeroy to processor

Question 32

Address bus?

Answer 32

transfers addresses processor to main memory

Question 33

machine code?

Answer 33

language computer understands, binary

Question 34

Advantages of machine code?

Answer 34

code runs very quickly, does not need to be translated

Question 35

Disadvantgers of machine code?

Answer 35

Difficult for humans to read and understand, only run on the processor type they have been written on

Question 36

High level languages?

Answer 36

created as a machine code is hard, uses english words and phrases

Question 37

Advantages of high level languages

Answer 37

contain english so easeir to read and understand, easier to spot errors, can run on more than one type of processor

Question 38

Disadvantages of high level languages

Answer 38

need to be translated into machine code are slower

Question 39

translators?

Answer 39

translates into machine code so computer can understand

Question 40

types of translators?

Answer 40

Interperter, Compiler

Question 41

Interperter?

Answer 41

Doesn't produce object code (standalone piece), translate one line a time

Question 42

Advantages of Interperters

Answer 42

errors are highlighted immediatly so easier to fix, it will run a partical or devoloping code

Question 43

Disadvangages of interperters

Answer 43

translation not saved, if code is repeated in a loop it runs many times, i ndividual runs slower

Question 44

Compliers?

Answer 44

translates high level language into machine or object code, line at a time saves into a file , don't need to translated again, lists errors , can not be run until all translated

Question 45

Advantages of compilers

Answer 45

If there is no errors does not need to be run again, translator only needed once

Question 46

Disadvantages of comilers

Answer 46

If syntax error won't run, errors may be harder to correct as not idenified till whole code translated

Question 47

GDPR?

Answer 47

General data protection regulation, into force 25th May 2018

Question 48

Implications of GDPR

Answer 48

Data processed fairly,lawfull and transparent manner used for declared purpose only limited to the data needed for declared purpose accurate not held for longer than neccessory held securely

Question 49

what is binary?

Answer 49

a simple two bit system, on/off, used by computers

Question 50

values in binary

Answer 50

128,64,32,16,8,4,2,1

Question 51

floating point reoresation?

Answer 51

represents very big or small numbers in scientic notation

Question 52

what is any number represented in (floating point)

Answer 52

mxb2e m=mantissa b=base e=exponment

Question 53

how to do floating point repersention

Answer 53

point moved in front of first 1 and e(power) must be in binary

Question 54

ASCII?

Answer 54

American standerd code for infornation interchange), was the most popular form of coding a character set

Question 55

what are the two 'types' of Ascii

Answer 55

8 bit extended (256 characters), 7-bit (standard)

Question 56

Whats in a character set

Answer 56

Letters a-z,A-Z, number symbols, punctuation, special characters, control characters

Question 57

what are the first 32 used for in ASCII

Answer 57

Control characters

Question 58

Control characters? Examples?

Answer 58

keys that send instructions without a symbol apperaing (e.g. Deleate key, escape key, tab)

Question 59

Advantages of ASCII

Answer 59

Uses latin characters & alphanumeric, uses less storage than unicode

Question 60

Disadvantages of ASCII

Answer 60

Only makes use of the english language, if unicode is read in ASCII it won't display character correctly

Question 61

two types of graphics

Answer 61

Bitmap and Vector

Question 62

Bitmap

Answer 62

Represented as a grid of pixals , each pixal contains a number of bits to store the colour, more bits more colours, if zoom in to far become pixelated

Question 63

Vector

Answer 63

picture is stored as a collection of mathmatically determined shapes or objects

Question 64

properties of a vector shape

Answer 64

start x&y coordinates, fill colour, line colour, width, height

Question 65

vector shapes?

Answer 65

Rectangle, ellipse, line, polygon