unit 1 Flashcards
1
Q
define cpu
A
central processing unit
2
Q
what components does the cpu have?
A
control unit, alu, buses and registers
3
Q
what is the role of the control unit?
A
part of the processor that co-ordinates activity of all other components
4
Q
how are control signals sent?
A
sent along the control bus between the control unit and other components
5
Q
what is a bus?
A
a series of connectors that transfer signals between internal components and exchange data
6
Q
what are the 3 buses in the cpu?
A
control bus, address bus and data bus
7
Q
what is the control signal memory read?
A
causes data from the addressed location in RAM to be placed on the data bus
8
Q
what is the control signal memory write?
A
causes data on the data bus to be written in to the addressed location in RAM
9
Q
what is the control signal, bus request?
A
indicates that a device is requesting use of the data bus
10
Q
what is the control signal, bus grant?
A
indicates that the CPU has granted access to the data bus
11
Q
what is the ALU?
A
arithmetic logic unit
12
Q
what is the role of the ALU?
A
problem solving part of the processor
13
Q
what is the role of the accumulator?
A
a single general purpose register that temporarily stores results and data
14
Q
what is the pc?
A
program counter
15
Q
what is the role of the pc?
A
holds memory address of the next instruction to be executed
16
Q
what is the cir?
A
current instruction register
17
Q
what is the role of the cir?
A
holds the instruction which is split into opcode and operand
18
Q
what is the mar?
A
memory address register
19
Q
what is the role of the mar?
A
holds the address in memory where the processor is required to fetch or store data
20
Q
what is the mdr?
A
memory data register
21
Q
what is the role of the mdr?
A
temporarily holds data moving between the processor and main memory
22
Q
what are the steps for FETCH in the FDE cycle?
A
- address of the next instruction is copied from the PC to the MAR
- the instruction held at that address is copied to the MDR
- contents of PC are incremented
- contents of the MDR are copied to the CIR
23
Q
what are the steps for DECODE in the FDE cycle?
A
- instruction held in the CIR is decoded
- it is split into operand and opcode to determine the type of instruction it is
- it is passed to the accumulator
24
Q
what are the steps in the EXECUTE for FDE cycle?
A
instruction is executed
25
what is a word?
memory divided into equal units
26
what does the width of the address bus do?
it determines the maximum possible memory addresses of the system
27
what would the max number of an 8 bit address bus be?
256
28
what is the role of the data bus?
holds data being sent to/from the CPU and RAM
29
what is the role of the address bus?
holds addresses being sent to/from the CPU to RAM
30
what is the role of the control bus?
sends signals to determine whether the other buses are in read or write mode
31
which factors affect CPU performance?
clock speed
number of cores
cache
32
what is the role of the clock?
controls operations within the CPU by sending pulses
33
how is clock speed measured?
how many state changes the CPU performs per second
34
what is the benefit of high clock speed?
high clock speed means a computer can execute more instructions per second and therefore executes tasks faster
35
what is a core?
a processing unit in the CPU
36
what are the benefits to having multiple cores?
more cores means tasks are carried out faster as each core can carry out a task (parallel processing)
37
what is a disadvantage to multiple cores?
some tasks can't be split between cores so having more cores is sometimes no quicker than having 1
38
what is cache?
primary storage that sits close/on the CPU
39
what is the role of cache?
used to store frequently used data and instructions
40
what is the benefit of having more cache?
closer to CPU than RAM so faster to retrieve data from, the more cache there is the more data can be stored which speeds up performance
41
what is pipelining?
the process of carrying out multiple instructions at the same time
42
how does pipelining work?
each instruction will be at a different stage of the FDE cycle, one is being fetched as another is being decoded and so on
43
how does pipelining improve performance?
it reduces latency
CPU is not idle while waiting for the next instruction which increases speed of execution
44
what is computer architecture?
how components and instructions make the computer function
45
what are the 2 types of architecture?
von neumann and harvard
46
what is the memory organisation like in von neumann?
unified memory
47
what is the memory organisation in a harvard architecture?
separated memory
48
what is the layout of the bus and control unit in von neumann architecture?
single bus and single control unit
49
what is the layout of the bus and control unit in harvard architecture?
separate bus and separate control units
50
what are the 2 types of processors?
CISC and RISC
51
what does a CISC stand for?
complex instruction set computer
52
what does a RISC stand for?
reduced instruction set computer
53
what are the features in a CISC?
larger instruction set
take more than one clock cycle to execute
less space in memory
more addressing modes
54
what are the features in RISC?
smaller instruction set
one clock cycle to execute each instruction
suitable for pipelining
fewer addressing modes
more complicated compilers
fewer addressing modes
55
where are CISCs used?
laptops and desktops
56
where are RISCs used?
smartphones and tablets
57
what are the advantages of a RISC?
costs less to manufacture
requires less power
58
what are the advantages of a CISC?
takes up less space in memory
less complicated compilers
59
what are the disadvantages of a RISC?
takes up more space in memory
60
what are the disadvantages of a CISC?
requires more power
costs more to manufacture
61
what is a GPU?
graphics processing unit
responsible for processing graphics to reduce the load on the CPU
62
what can GPUs be used for?
graphics
3D modelling
data modelling
financial modelling
data mining
performing complex calculations
machine learning
calculations on multiple data sets at the same time
63
how can GPUs be used in 3D modelling?
can be used to render lighting effects and shadows
64
how can GPUs be used in data modelling?
can handle large datasets and sort/filter data
65
how can GPUs be used in financial modelling?
used to simulate different scenarios in risk modelling, option pricing
66
how can GPUs be used in data mining?
process of analysing large amounts of data to find patterns
sorting, searching, pattern recognition
67
how can GPUs be used to perform complex calculations?
matrix multiplication, numerical simulations, differential equations
68
how can GPUs be used in machine learning?
involves training a computer on massive amount of data
can speed up the process of making predicitions on new data
69
what types of tasks are GPUs suited for?
specialist instructions
multiple cores - smaller cores optimised for parallel processing, execute calculations simultaneously
SIMD processing - single instruction multiple data processing
70
what are the benefits of using a GPU and explain them
parallel processing - can handle many tasks simultaneously as they are multicore processors
speed - speeds up tasks due to pp
efficiency - more calculations per unit of power consumed in comparison to CPUs making them more energy efficient
71
what is a multicore system?
system that has more than 1 processing unit in a single processor which can independently process instructions at the same time
72
what are the benefits of multicore/parallel processing?
speed
improved performance
better resource utilisation
problem solving
real time applications
73
explain the benefit of speed in pp
If a task can be divided into subtasks that can be executed simultaneously, the total execution time can be reduced
74
explain the benefit of improved performance in pp
Simultaneous computation can take place on different data subsets (this would be used in machine learning, data mining and scientific computing)
75
explain the benefit of better resource utilisation in pp
Parallel processing allows for better use of computer resources as multi-core or multiple processors can be used more effectively
76
explain the benefit of problem solving in pp
Problems which are large and complex (which lend themselves to parallel processing) can be solved more easily
77
what are input devices?
devices which transfer data and control signals to a computer system
78
what are the examples of input devices?
keyboards, microphones, touch screens, interactive whiteboard, trackpad, card reader, NFC reader, flatbed scanner, OMR scanner
79
what is the purpose of a keyboard?
allows user to enter character data
lets user send signals to control volume or switch windows
80
what is the purpose of a mouse?
allows a user to point and click, position cursor on the screen
81
what is the purpose of a trackpad?
user controls movement of the cursor using their fingers
82
what is the purpose of a graphics tablet?
used to create digital drawings
83
what is the purpose of a microphone?
captures analogue sound waves and converts them into electronic signals
84
what is the purpose of a flatbed scanner?
allows users to scan a physical document such as a photograph and save it as a digital bitmap image
85
what is the purpose of an OMR scanner?
OMR = optical mark recognition
input answers from multiple test paper
86
what is the purpose of a magnetic card reader?
hotel doors ...
reads data in magnetic strip of card
87
what is the purpose of a smart card reader?
reads data from an embedded integrated circuit chip
88
what is the purpose of a NFC reader?
reads fata from Near Field Communication tag
uses radio waves to read data from a bank card of phone when close to each other
89
what is the purpose of a touchscreen?
same device as display screen can be used to input data
allows user to touch and use finger to navigate tasks
90
what is the role of a trackerball?
have ball on top of device which tracks movement of user
91
what is the purpose of a barcode?
representing data in machine readable form
represented by parallel lines with varied width and spacing
read by laser, reflected light is turned into binary code
92
what are QR codes?
quick response codes which contain links to websites
93
what is a biometric?
a physical characteristic like fingerprint, irises, voice
94
what is the role of sensors?
to collect data in analogue form and convert it to digital data to be processed
95
what are the different types of sensors?
gas, light, temperature, pressure, pH, magnetic field, moisture, acoustic, infra-red
96
what are the applications for a temperature sensor?
heating system in house
heat output of chemical process
in a greenhouse
97
what are the applications for a moisture sensor?
control dampness of soil, dampness of air, in a factory making microchips
98
what are the applications for a light sensor?
switch street lighting on at dusk
switch car headlights on automatically
99
what are the applications for a infra-red sensor?
turn on a car's windscreen wipers
detection of intruders
count number of people in airport
100
what are the applications for a pressure sensor?
detection of intruders
weight of vehicle
forecast weather
101
what are the applications for a acoustic sensor?
pick up noise levels in a burglar alarm system
detect noise of liquids
monitor sound level
102
what are the applications for a gas sensor?
monitor co2 in a river,
carbon monoxide in house
103
what are the applications for a pH sensor?
monitor acidity levels in a chemical process
measurement of pollution levels in river
check acidity levels in soil
104
what are the applications for a magnetic field sensor?
used in smart phones so they know which direction we in
motors of CD players
vehicle anti lock braking systems
105
what is monitoring?
reporting values of sensors
106
what is control?
output can alter how process is operating
can change value of next input
107
what are output devices?
devices which take data produced by a computer and turn it into human readable form
108
what are some output devices?
printers, screens, loudspeakers and multimedia projectors
109
what are the different types of printers?
inkjet, laser, dot matrix, 3D
110
what are the key features of inkjet printers?
liquid ink produces richer colours
sold at low cost but cartridges are very expensive
111
what are inkjet printers used for?
printing photo quality images
112
what are the features of a laser printer?
- use toner = dry powdered ink
- print quality is excellent
- fast and reliable
113
what are laser printers used for?
used in printing posters, labels, brochures
114
what are the features of a dot matrix printer?
- known as impact printers
- strike an inked ribbon which imprints dots to form letters
- can work in damp atmospheres
- noisy, poor quality, expensive
115
what are dot matrix printers used for?
mailing labels
black and white printing
in factory settings
116
what are the features of a 3D printer?
- can print using plastic filament, metal powder, ceramic
117
what are the applications of 3D printers?
medicine: prosthetic limbs, reconstructive surgery
art: prototypes for designs or parts of machinery
118
what are the dangers of 3D printing?
- working gun was created and shared online
- uses plastics
- reduction in jobs
- design inaccuracies
- copyright issues
119
what is RFID?
radio frequency identification
technology that uses radio waves to track tags attached to objects
120
how do RFID systems work?
use a transponder and a receiver
powered receiver emits radio frequency/waves
transponder antenna becomes energised
then sends data to receiver
121
what is the use of RFID tags?
- security control points, ID of people, animals, goods
- shipping and supply chain tracking
- banking systems
122
what is the difference between passive and active tags?
passive: used in bank cards, have no power source, rely on radio waves, transponders need to be close to receiver
active: use a large battery powered beacon, broadcasts its own signal, useful for larger items
123
what are actuators?
motors which are commonly used in conjunction with sensors to control a mechanism
124
how do LCDs work?
liquid crystal display
contains groups of red, green, blue diodes to form each pixel
125
why do we use LEDs to back light LCD screens?
- reach max brightness almost immediately
- image is sharper with more realistic and vivid colours
- produce brighter light leads to better picture definition
- allows screen to be much thinner
- last almost indefinitely
- consume very litter power so produce very little heat
- reduce running costs
126
compare OLED screens with LCD/LED screens
- plastic, rather than glass also makes them flexible
- light emitted from OLED is much brighter than LCD/LED
- larger field view than LCD
- better for phones, watches
127
what is primary memory?
RAM and ROM
128
what does RAM stand for?
random access memory
129
what does ROM stand for?
read only memory
130
what does RAM store?
operating system
running programs currently in use
131
what does ROM store?
bootstrap instructions
BIOS
132
what happens to RAM when power is lost?
volatile so content is lost
133
what happens to ROM when power is lost?
non volatile so contents are retained
134
what happens in RAM when computer is turned on?
programs are copied from RAM to secondary storage
data in programs are stored in RAM so it begins to fill up
135
what is thrashing?
when more and more apps are on virtual memory and OS is busy managing that rather than processing tasks
136
what happens in ROM when computer is turned on?
137
what are the 3 types of secondary storage?
magnetic, optical, solid state
138
how does magnetic storage work?
- concentric tracks on a magnetic disk
- disk spins at high speed
- spinning platters are read by drive heads
- magnetised or not magnetised, 1, 0
139
how do solid state drives work?
- data stored electronically on flash memory
- uses tiny cells that trap electrical chargers representing bits of data
140
how does optical storage work?
- store data by using a laser to create tiny pits and lands on a reflective surface of a disc
- laser beam reads them as 0 and 1
141
what are the features of magnetic storage?
- hard disks have very high capacity
- fast read and write speeds
- relatively cheap storage per TB
142
what are the features of SSD?
- more durable
- no moving parts
- portable
- faster than hard disk drive
- consume less power
- more expensive
143
what are the different CD formats?
CD ROM
CD R
CD RW
144
what is CD ROM?
- CD pressed at the time of manufacture
- used widely for software distribution
145
what is CD R?
- may be used for copying a game, video file
- can be written to once
146
what s CD RW?
-can be read many times, written and erased and written again
- useful for short term backup, transferring files from one device to another
