Characteristics Of Processors, Storage and I/O Devices Flashcards
What is the system bus made up of
The address, control and data bus
What is meant by a bidirectional bus
It allows two-way connection between internal components of the system
What is meant by the bus width
Bus width is the number of parallel lines a bus has
What is the data bus used for
To transfer data and instructions between components
What is the address bus used for
To specifiy the address of a memory location to either read or write data to that memory location
Is the address bus bidirectional or unidirectional
Unidirectional
What is meant by a unidirectional bus
There is only a one way connection between the component and the bus
What is the role of the control bus
Transfers control signals used to manage the operations that take place inside a computer system
What does the control signal, memory read, do
Places data from a specific memory location onto the address bus
What does the control signal, memory write, do
Stores data from the data bus onto a specific memory location
What does a bus request do
Signifies a component requires access to a bus
What does a bus grant do
Signifies a component has been given access to a bus it had requested
What does a bus busy signal do
Signifies that a bus s not available for use
What does an interrupt request do
Signifies that an error or exception has occurred that requires immediate attention from the processor
If a data bus has a width of 8, how many bits can it transfer per second
8 bits
If an address bus has a width of 8, how many bits can it transfer per second
2⁸ bits
What the role of the control unit
Organises the sequence in which program instructions are executed
What is the role of the ALU
Performs arithmetic calculations and logical operations (Add, Sub, NOT, XOR, binary shifts etc)
What is the role of the system clock
Oscillates between 0 and 1, which synchronises all operations
What is a register
Fast access memory that stores frequently used data
Name the 5 special registers
PC
CIR
ALU
MAR
MDR
Give an example of a general purpose register
Accumulator
What happens during the fetch phase of the FDE cycle
- Address in PC copied to MAR
- Data at address copied to MDR
- Simultaneously the PC increments by 1
- Data in MDR copied to CIR
What happens during the decode phase of the FDE cycle
- CU decodes data in CIR
- Data is split into opcode and operand
What is the significance of opcode and operand
Determines how the instruction is carried out
How does having multiple cores improve performance
More data processed simultaneously, as each core can execute FDE cycles independently
Why more cores not impact performance
The impact depends on the nature of the task. Not all programs are designed for multi core processing
Describe L1 cache
Part of the circuitry of the cores, the smallest but fastest cache
Describe L2 cache
Part of the circuitry of each core, larger than L1 but slower
Describe L3 cache
Slower than L2 but larger, built next to processor on motherboard
Why is it advantageous for cache to be part of the circuitry of each core
Reduces the time taken for data to pass through registers
What is clock speed a measure of
The amount of state changes per second, 0 to 1, which determines the amount of cycles per second
What is overclocking
Performing more instructions per second than the recommended amount
What is the negative of overclocking
Causes the processor to overheat
Describe pipeling
Where one instruction is being executed, another is decoded and a third is being fetched
What is the advantage of pipeling
Components don’t remain idle, improving efficiency and therefore performance
Give 2 things Von nuemann architecture consists of
3 from:
A processor
Shared memory unit connected to processor
I/O controller
Shared address and data bus
Give 2 features of harvard architecture
Instructions and data have separate memory locations
Uses different address/ data bus for Instructions and data
Give two advantages of von nuemann architecture over harvard
Cheaper
More flexible
Give one advantage of harvard architecture over von nuemann
Can simultaneously read/ write data while getting instructions, stopping components from being idle
Describe the instruction set of a RISC processor
Simple commands that each take the same time to execute, where one instruction is carried out per clock cycle
Why do RISC processors take up more storage when carrying out basic tasks compared to CISC
Due to the simple instructions, several are needed to execute the task which requires more memory and also takes up more time
Give 2 positives of RISC having simpler instructions
- Makes it easier to implement pipeling
- Requires less circuitry, so cheaper and less power used
Describe the instruction set of a CISC processor
Large number of instructions which are complex and take varied lengths to execute
Does RISC make good use of RAM
No, it uses a lot of RAM to store instructions which can cause system bottlenecks
What is an input device
A peripheral used to provide data and control signals to a computer system
What is a biometric device
A device that uses physical traits of a person such as finger prints and facial ID to gain access to a device
What is biometric spoofing
A term used to describe a method of fooling biometric scanners
How do sensors convert analogue signals into digital form
Using an ADC, analogue to digital converter
Give 2 examples of sensors in a mobile phone
Two from:
Ambient light sensor
GPS receiver
Magnetometer
Gyroscopes
Accelerometers
What is the purpose of an RFID (radio frequency identifier)
Allows data to be transmitted wirelessly over radio waves
Describe the composition of an RFID tag
Made up of an antenna, for sending and receiving radio signals
A chip that processes the signals
It’s own unique identifier
How does a barcide reader work
Illuminates the barcode. More light is reflected by the white area and this light us captured by photoelectric cells which generate a binary value that corresponds to the bar code
What is an output device
A peripheral that reproduces or displays data/ information from a computer system
What criteria should be considered when choosing a suitable printer
Speed
Print resolution
Quality of colour reproduction
Paper handling
Cost of consumables
What is printer resolution measured in
Dots per inch (dpi)
Give two examples of non-contact printers
Inkjet printer
Laser printer
Compare inkjet printers to laser printers
Use liquid ink, laser user powdered ink (toner)
Slower than laser printers
Can produce photo quality images, laser can’t
Give 3 advantages of SSDs over HDDs
Faster access speed
Lower risk of mechanical failure due no moving parts
Less energy consumption due to less moving parts
Silent operation
Give 3 advantages of HDDs over SSDs
Larger capacity
Longer lifespan
Cheaper
Give 2 advantages of optical media
Cheap
Portable
Give two disadvantages of optical media
Susceptible to damage (scratching, exposure to sunlight)
Low storage capacity in general
Describe cloud storage
Where data is managed by commercial organisations and stored outside of your computer system
Give 1 Pro and con of cloud storage
Pro: Convenient
Con: Performance based on Internet connection
What us the maximum amount of RAM dependent on
The width of the address bus
Give 3 instances of parallel processing
Pipelining
Array/ vector processing
Multicore processing
Describe array/ vector processing
SIMD (single instruction multiple data)
Uses multiple ALUs to perform one instruction on a large data set simultaneously
Describe multicore processing
MIMD (multiple instruction multiple data)
Each cpu has multiple cores/ each computer has multiple CPUs e.g. a supercomputer
What is a co-processor used for
To perform routine mathematical tasks, freeing time for the core processor to perform separate tasks
