3. hardware Flashcards
what does the CPU do
the CPU proceses instructions and data that are input into the computer so that the result can be output
what is the microprosesser
the microporocessor is a type of intergrated circuit on a single chip
what are the units of the cpu
- arithematic logic unit- responsible for carying out mathamatical calculation
- control unit- manages the other components
what are the registers of the cpu
-PC:
- MAR:
- cir
- MDR
- ACC
pc
-PC: holds the address (memory location) of the next instruction to be fetched.
MAR
s also used when reading and writing data to and from RAM. The MDR will contain the data to be written to RAM, or the data that has just been read from RAM.
CIR
holds the instruction which is currently being decoded or executed.
ACC
is used to hold the data being worked on by the ALU
what is the control bus
The control bus carries control signals from the Control Unit to other components of the CPU. and read and write signals
what is the adress bus
the adress bus carries adresses from the memory adress register to the RAM, to indicade wgich adress will be selected. only 1 direction
what is the data bus
a data bus carries data from the memory data register to the RAM during a write operation, the data bus carried data from the RAM to the memory data register during a read operation. bidirectional
explain the fetch decode execute cycle
-the pc contains the adress of the next instruction
- the contents of the PC are copies to the MAR
- the pc is incrimented by 1 so it still points to the next instruction
- the adress bus carries the value in the MAR to the RAM
- the control bus sends a ‘read’signal to RAM
- the data bus carries the contents of the desired RAM adress froom the RAM to the MDR
- the contents of MDR is sopies to the CIR
- the control unit decodes data
- ALU executes
what is the clock speed of the cpu
- usually measured in GHz
-determains the number of cycles a CPU can perform each second
more speed can generate more energy and heat
what are the cores of the cpu
a processer within the cpu. only 1 core can occur at a time.
what is the cache of the CPU
the cache is extremely fast memory that is located within the CPU. it is used to store temporary copies of the data in most commonly accessed RAM locations.
purpose of instructions set for a CPU
- An instruction set is a list of all the commands
that can be processed by a CPU and the
commands are machine code
the purpose and characteristics of an
embedded system and identify devices in which
they are commonly used
An embedded system is used to perform a
dedicated function, e.g. domestic appliances,
cars, security systems, lighting systems or
vending machines. This is different to a general
purpose computer that is used to perform many
different functions, e.g. a personal computer (PC)
or a laptop
barcode scanner
shine a light at barcode and measure the reflected light to read the data- quick, accurate, efficient
digital camera
uses a image sensore to measure light and take phototgraph, which is stored digitally on a device.
keyboard
allows users to type text and numeric data- reduced number of mistakes, limited operations
microphone
allows sound to be input. the sound can be playback at any time
mouse
control curser on screen
QR code scanner
represents small text characters using black and white pattern. store URLs. quick, requires internet, nfinate patterns
touch screen
input data using finger- user friendly, select from a small range of options.
resistive- uses very thin metal sheets over screen, pressure of contact complete ciruit
capacitive- transparent layer sensitive to static electrical charge in the human body
infrared- grid of infra red light over the screen. this grid is ivisable to users. light beams are broken info is detected.
2D scanners
documents are laid flat on the device and light is used to scan the document into a digital image. OCR software scan texts.
3D scanners
canning an object using lasers to measure the dimensions (height, width, depth) of an object. The laser detects details about the shape of the object and converts this into digital data
what is a actuator
An actuator takes a digital signal and outputs it as a physical movement.
eg: automatic door system.
what is a 3d printer
building up thin layers of material, layer by layer, until the object is complete. Objects are usually created from plastic filaments (such as ABS or PLA plastic) or from resin.
how does speaker work
speaker produces output in the form of sound, by converting electrical signals into vibrations.
how does LCD moniter work
work by sandwiching crystals between two sheets of glass. A white back light illuminates the screen from behind. When the crystals are solid, light cannot pass through. When an electrical current is applied to the crystals in individual pixels, light is passed through and an image forms.
worse quality, cheaper, use more energy
how does LED moniter work
Instead of using a fluorescent backlight, LED displays use light emitting diodes to generate the light. This often results in better contrast.
better quality uses less electricity but is more expensive
how do LCD projecters work
create an image by projecting light in three colours: red, green and blue. These colours are combined to form a final image on the projector screen.
bigger and better quality
how do DLP projectors work
use thousands of tiny mirrors to reflect a digital image from a computer onto a screen.
smaller and less quality
how do inkjet printers work
se ink cartridges to spray tiny droplets of ink at a piece of paper to form an image. use psysoelectric technology and thermal bubbles. when buiffer is empty stop printing. Inkjet printers are comparatively cheap and, although they can be slow, they can produce high-quality images with excellent colour blending.
how do laser printers work
use a laser to apply a static charge to areas on the paper. Toner (a powdered ink) is then attracted to the static charge and sticks to the paper in these areas, forming an image. higher quality but is more expensive.
acoustic sensor
detects sound
eg: burgler alarm, unhearable sound
accelerometer sensor
measures acceleration force
eg: smartphones, cars
flow sensor
measures flow speed of liquid
eg: detect leaks
gas sensor
detect precense of gases
eg: toxic gas in manufacturing plant, oxygen levels
humidity sensor
detects water vapour in air
eg: greenhouse
infra-red sensor
detecs anfra red light
eg: automatic door, alarm systems
level sensor
ses a gyroscope to measure angular movement. This enables the sensor to detect if it is being tilted or rotated. A common application for these sensors is in smart phones, which can be controlled by tilting or waving the device.
light sensor
eg: switching lights
magnetic field sensor
A magnetic field sensor measures the strength of a magnetic field. They are sometimes used in geophysical surveys.
moisture sensor
A moisture sensors measures the presence of water.
ph sensor
A pH sensor detects how acidic or alkaline a substance is. pH sensors might be used in swimming pools or aquariums to check the pH of the water, or in a chemical factory to help ensure the pH level is correct.
pressure sensor
A sensor which measures the pressure of a liquid or gas, such as in a pipe.
A sensor which means the weight pushing down on it, such as a floor plate which can detect the pressure of a person standing on it.
proximity sensor
closeness of ojects
eg car parking, robots
temperature sensors
measure heat
eg: microwaves, central heating, engine systems
what is primary storage
storage that is directly accessed by the CPU. there is the RAM and the ROM
what is the RAM
- temporary storage for data that is being currently used
- is is extremely fast and volatile
what is the ROM
- the rom is read only memore that cannot be altered or deleted.
- it is permenant and non- volatile
- they tell the computer how to communicate with other devices
what is secondary storage?
storage is not directly accessed by
the CPU and is necessary for more permanent
storage of data
what are the three types of secondary storage
manetic, optical and solid state
what is magnetic storage
Magnetic storage uses platters which are divided
into tracks and sectors. Data is read and written
using electromagnets and spinning.
cheap, relativly fast, hold a lot of data.
eg:HDD
what is optical storage
uses lasers to create and read pits and lands, which are 1s and 0s. they are read using light in the spinning disk.
eg: DVD, CD
it has low storage capacity, good for long term, transportable, can break easily
What is solid state storage?
Solid-state (flash memory) uses NAND or NOR
technology. Transistors are used as control gates
and floating gates
has no moving parts, quiet, durable, requires less power, portable, high cabacity, small
eg:SD memory card, usb
what is virtual memory
virtual memory is a secondary storage where chunks of data calles pages are moved from the RAM when in need for more space. calles paging out.
it is very slow
what is cloud storage?
Cloud storage can be accessed remotely in
comparison to storing data locally. physical servers and storage are needed to store
data in cloud storage
what are the advantages of local storage?
- fast
- more cost effective in the long run
- data is fully under users control
- data is accecible with no internet
disadvantages of local storage
- can only be accesed on local computer,
- risk of hardware failue
- use is responsible for backups and copies
advantages of cloud storage
- users can log in from anywhere
- additional storage can be addes very quickly
- ability to colaborate
disadvantages of cloud storage
- needs internet
- slower than local
- monthly costs
- privacy is at risk since anyone can access it
- enviormental concerns with use of energy
what is the use of a netwrok interface card?
NIC is a hardware which is needed to connect a computer to a network. NIC cab use a cable or wirless router to connect to net.
what is a MAC adress
a unique adress of a NIC which are unique to every network card created- it cannot be altered. a mac adress is 48 bits long
how is a mac adress written and how is it created?
in hexadecimal, created using the manufacturer code and the serial code
what is a IP adress
s a unique address assigned to each computer on a network.
what do IP adresses do
IP addresses are essential for identifying and managing computers on the network.
what are the 2 types of IP adress
- A computer may be assigned a static IP address, meaning it is given the same address every time it joins the network
- or it may have a dynamic IP address, meaning it is assigned any available address when it joins the network
what are routers
A router sends data to a specific destination on a
network
* A router can assign IP addresses
* A router can connect a local network to the
internet
