1.1 Characteristics of contemporary processors Flashcards
What is stored in RAM
Operating system, running programs, data currently being used
What is an input device?
Transfers data from an outside source to the computer
List some input devices
Keyboards and Keypads
Pointing devices
Microphones
Touch screens
Interactive whiteboards
Scanners
Cameras
Bar code readers
QR readers
What is a sensor
A hardware device that can take measurement of physical properties, such as temperature or pressure, from real world surroundings. These measurements are usually a representation of the actual property being measured
What is analogue data
Data that has no discrete value and can take any value to any measure of precision
List some types of sensors
Gas
Infra-red
Light
Temperature
Pressure
pH
Magnetic field
Moisture
Acoustic
List some applications of temperature sensors
Control the central heating system in a house,
Control or monitor the heat output in a chemical process,
Control or monitor the environmental temperature in a greenhouse
List some applications of moisture sensors
Control or monitor the dampness of soil in a greenhouse,
Control or monitor the dampness of the air in a greenhouse,
Monitor the dampness levels in a factory making microchips
List some applications of light sensors
Switch street lighting on at dusk and switch street lighting off at dawn,
Automatically switch a car’s headlights on when it gets dark,
To close or open the window blinds in a greenhouse to maintain light levels
List some applications of Infra-red sensors
Turn on a car’s windscreen wipers automatically when it starts to rain,
Detection of intruders in a burglar alarm system,
Count the number of people entering or leaving a supermarket
List some applications of Pressure sensors
Detection of intruders in a burglar alarm system,
Checking the weight of a vehicle on a weigh bridge,
Measurement of air pressure to forecast weather
List some applications of Acoustic sensors
Pick up noise levels (e.g. footsteps) in a burglar alarm system,
Detect the noise of liquids dripping from a pipe in an oil refinery,
Monitor the sound levels in a car factory
List some applications of Gas sensors
Monitor CO2/O2 levels in a river,
Monitor CO2/O2 levels in the air in a greenhouse,
Check for the carbon monoxide levels in a car exhaust system
List some applications of pH sensors
Monitor or control the acidity levels in a chemical process,
Measurement of pollution levels in a river,
Check acidity levels in the soil in a greenhouse
List some applications of Magnetic field sensors
Used in smart phones so they know which direction it is pointing,
Used in the motors of CD players,
Used in vehicle anti-lock braking systems
What is an output devices
Take data produced by a computer and turn it into a form recognisable by humans
List some output devices
Monitor
Printer
Speakers
Actuators
Headphones
Projector
What are the different types of monitors
LED
OLED
Benefits of LCD over OLED
Cheaper
Benefits of OLED over LCD
Plastic - Flexible
Brighter
Less heat produced
No need for back lighting
Much less power is consumed
What are the different types of printer
Inkjet
Laser
Dot matrix
3D
What are the advantages of Inkjet printers
Inexpensive
What are the advantages of laser prints
Toner cheaper than ink and lasts longer
Print quality is better
Fast and reliable
What are the advantages and disadvantages dot matrix printers
As: useful when multi-part stationery is required, can work effectively in damp or dirty atmospheres
Ds: Noisy, poor print quality, expensive to buy
What is RFID
Radio Frequency Identification - system of inputs and outputs used to wireless-ly communicate for payments or other things
What does RAM stand for
Random Access Memory
What does ROM stand for
Read Only Memory
What is stored in ROM
Basic instructions for booting the computer and loading the operating system
What kind of memory is RAM
Volatile
What kind of memory is ROM
Non-volatile
What is virtual memory?
A portion of the hard disk designated to function as additional RAM. When RAM fills up less important data and instructions are moved to virtual memory
What kind of storage is secondary storage
Non Volatile
What factors should be considered when picking secondary storage
Durability
ReadWrite Speed
Capacity
Portability
Cost
Lifespan
How do hard disk drives work
Magnetic disk with a read write head that changes the polarity of spots on the magnetic disk with positive = 1 and negative = 0
What are the advantages and disadvantages of hard disk drives
Durability: Bad
ReadWrite Speed: Good (better than SSDs)
Capacity: Good
Portability: Bad
Cost: Good
Lifespan: Infinite
How does cloud storage work
Involves uploading data to a remote server or computer via the internet.
What are the advantages and disadvantages of cloud storage
Durability: Infinite
Readwrite Speed: Bad
Capacity: Infinite
Portability: Very good
Cost: Free - then expensive
Lifespan: Infinite
How do solid state drives work?
Contains multiple memory chips, which are controlled by software to make them act like a disk drive
What are the advantages and disadvantages of solid state drives
Durability: Good
Readwrite Speed: Good (worse than HDDs)
Capacity: Average
Portability: Good
Cost: Bad
Lifespan: Finite
How does optical storage work?
Stores data by using lasers to read and write data on to an optical disk by creating pits and lands that represent 0s and 1
What are the advantages and disadvantages of optical storage
Durability: Bad
Readwrite Speed: Bad
Capacity: Average
Portability: Good
Cost: average
Lifespan: Infinite
What is the CPU
Central processing unit, processes all instructions and controls all activity within the computer
Describe the purpose of the control unit
Sycronises instructions using clock, sends control signals down the control bus to coordinate activities
Define a bus
A wire or set of wires that connect internal components that signals are transferred along
What does the data bus do
Carries data and instructions between CPU and RAM
What doess the address bus do
Carries information on the data location
What does the control bus do
Carries control signals to coordinate and control activity
What are some control signals
Memory read, Memory write, Bus request, Bus grant, Clock
What does the memory read signal do
Places data from addressed location in RAM to be placed on data bus
What does the memory write signal do
Writes data on data bus to addressed location in RAM
What does the bus request signal do
Indicates that a device is requesting use of the data bus
What does the bus grant signal do
Indicates the CPU has granted access to the data bus
What does the clock signal do
Synchronises operations
What does the ALU do
Preforms all arithmetic and logical operations for the processor
What does an ALU take inputs as
An instruction consisting of an operator and an operand
What is an operator
What is to be done
What is an opperand
The data or address to be operated upon
What is an opcode
The symbol or representation for the operator
What are registers
Very small areas of superfast memory on the CPU used to temporarily store data
What is the PC and what does it do
Program counter - holdes the memory address of the next instruction to be executed
What is the CIR and what does it do
Current instruction register - Holds the current instruction
What is the MAR
Memory address register - holds the address of the the next daya instruction
What is the MDR
Memory data register - temporarily holds data moving between processor and main memory
What is the ACC
Accumulator - holds intermediate results of instruction such as the result from the ALU
What is the PC
Program counter - holds address of nect instruction
What are steps of Fetch in the Fetch execute cycle (4)
Address of next instuction copued from PC to MAR, instruction at that address copied to MDR, contents of PC incremented, contents of MDR copid to CIR
What are the step of decode (3)
Instruction in CIR decoded, split into operand and opcode to determine what type of instruction it is and additional data is fetched, data is passed to ACC
What are the characteristics of von Neumann architecture(2)
Single control unit that sequentially works through instructions, instructions and data are stored in a commom maim memory transferred using a single shared bus
What are the steps of execute (1)
Instruction is executed by ALU and stored in memory
What is the problem of von Neumann Architecture
Bottlenecking: the data required by an instruction cannot be transferred at the same time as instuction, so loys of processor time is spent idle
What are the advantages of von Neumann architecture
Simplifies the design of the control unit, and data and memory accessed the same way lowering cost and programming complexity
What are the characteristics of Harvard architecture (3)
Instructions and data stored in different locations, data and instructions transferred over different buses, data and instructions have different word lengths
What are the advantages of harvard architecture
Avoids bottlenecking, thus is faster
What are the disadvantges of harvard
More expensive - as complexity is much higher
Where is harvard architecture used
Embedded systems and DSPs
What is a DSP
Digital signal processor - takes a digital signal and makes it clearer, improving accuracy and reliability
What kind of signals does DSPs act on
video, voice, auido, temperature or position signals that have been digitised
How does a DSP clean signals
Rapidly preforms mathematical functions on them
What are the characteristics of modern architecture
RAM uses von Neumann while cache uses harvard
What is CISC
Complex instruction set computers, have a large instruction set used to accomplish tasks in as few lines of assembly as possible
What is RISC
Reduced instruction set computers, have the minimum number of instructions, each taking one clock cycle in multiple general purpose registers
Compare cisc to risc
complex instruction - simple, large range of instructions - fewer, many addressing modes - fewer, many instructions can access memory -only Load and Store, processor comples - simple
Advantages of CISC(3)
Quicker to code, compiler has to do less work, less RAM used to store instructions
Advantages of RISC(3)
Hardware is simpler to build, pipelining is possible, RAM is cheap and RISC allows better preformance at less cost
What are parallel systems
Multicore processors, able to distibute workload accross multiple processor cores, thus acheiving higher performance by preforming several tasks in paralell
What is a co-processor
An extra processor used to supplement the functions of the CPU, can only carry out a limited range of functions
What is a GPU
A specialised processor designed to be very efficent at manipulating computer graphics
How is the GPU designed
Has thousands of small efficient cores designed for paralell processing
What else can a GPU do(3)
Model physical systems, audio processing, breaking passwords
