4.7 Fundamentals of computer organisation and Architecture UPDATED Flashcards
What is the role of processor
primary role is to execute instructions stored in the computer’s memory
Where does the address bus send and receive data from
Uni directional bus from processor to I/O or memory
Where does the data bus send and receive data from
Send: CPU, Memory and I/O
Receive: CPU, Memory and I/O
Where does the control bus send and receive data from
Send: CPU, Memory, I/O
Receive, CPU, Memory, I/O
What is the role of the main memory
Main memory holds the data and instructions that the processor needs to access quickly during program execution
Role of the io controllers
facilitating communication between the CPU and various input/output devices, such as peripherals.
What are the three types of bus found within the cpu?
address buss, data bus, control bus
What is the role of the address bus(3)
A pathway specifically for transmitting memory addresses.
When the CPU wants to read from or write to a specific location in memory
it sends the address of that location via the address bus.
What is the role of the data bus
the pathway through which data travels within a computer system
What determines the load capacity of the data bus
The width of the data bus determines how much data can be transferred at once.
For example, a computer might have a 32-bit or 64-bit data bus, meaning it can transfer 32 or 64 bits of data simultaneously
What is the function of the control bus
Responsible for coordinating and controlling the various activities within the computer system.
It carries signals that indicate the type of operation being performed
It also carries timing signals to synchronize the activities of different components.
Explain the von neumann architecure
- shared memory space for data and instructions in same format
- a single processor unit follows a linear fetch decode execute cycle one instruction at a time.
- registers are used for fast access to instructions and data.
Where is the Harvard architecture system typical used
Embedded systems such as digital signal processing
Where is the Von Neumann system typically used
Typically used in general purpose computing systems
Explain the harvard architecture system
- instructions and data are stored in separate memory units
- each has its own bus
- reading and writing data can be done at the same time as fetching.
What is addressable memory
Addressable memory enables the processor to read from or write to specific memory locations as needed during program execution.
What is the stored program concept (3)
The idea that:
machine code instructions and data are stored in
main memory
instructions are fetched from memory and executed serially
by a processor that performs arithmetic and
logical operations.
What is cache memory
Memory that can be accessed very quickly located near the processor
How does increasing amount of cache memory improve performance of a processor.
- More instructions/data can be stored in the cache
- Instructions/data stored in cache can be accessed more quickly than instructions/data in main memory
Describe the role of the control unit (3)
- Controls fetch execute cycle
- Synchronise operation of processor
- Control Transfer of data between registers
What are registers (2)
small, high-speed storage locations within the CPU
used for storing and processing data and instructions during computation.
What are the six types of register found in CPU
MAR - Memory address register
MBR - Memory buffer register
MDR - Memory data register
IR - Instruction register
PC - Program counter
Accumulator
Explain how the Fetch-Decode Execute cycle is used to
execute machine code (7)
When an instruction is to be fetched the program counter contains the address of the next instruction.
The address is then copied into the memory address register
It is then sent along the address bus
Control unit sends memory read signal via control bus to the memory controller to retrieve the instruction
Contents in the correct address are transferred along the data bus.
Value from instruction goes to the CIR
Instruction in CIR is decoded by decode unit
What is the role and operation of the ALU
Part of processor that performs mathematical, logical, and data processing operations.
What is the role and operation of the Control unit within the fetch execute cycle
Fetch data from memory to decode them and execute them serially
What is the role and operation of the general purpose registers
Can be used to hold data and instructions temporarily
What is the role and operation of the dedicated registers
Used by processors to carry out a specific role
What is the role and operation of the program counter
Register that holds the address of the next instruction being fetched
What is the role and operation of the current instruction register
Used to store the instruction that is to be decoded and executed
What is the role and operation of the memory address register
Holds the address of the current instruction being executed
What is the role and operation of the memory buffer register
Holds the instruction from the MAR and the associated data
What is the role and operation of the status register
Used to hold the status of various flags indicating positive results or negative result or interrupt status
What is meant by the term ‘processor instruction set’
The set of machine code instructions that a particular type of processor can understand
What is meant by opcode
represents the basic machine operation of the machine code instruction
What is meant by operand
A value or address that forms part of a machine code instruction
Describe the makeup of instructions
Consists of opcode and operand
What is immediate addressing
When the data in the operand is fixed meaning it is immediately available for use
What is direct addressing
Code is directly referred to a memory location
Describe the role of interrupts and interrupt
service routines (ISRs); their effect on the
Fetch-Execute cycle
Interrupts can be generated by hardware of software when detecting an error or illegal operation.
Once interrupt is generated, if it is high priority it causes the fetch execute cycle to be interrupted after completing current instruction
Describe the Interrupt service routine
Interrupted task is stored - program counter contents stored in memory,
current instruction finishes execution,
register contents stored in memory
Interrupt service routine is carried out
Interrupt number examined
source of interrupt identified,
program counter loaded with start address for interrupt service routine
which is executed.
Continue Interrupted task
What effect does multiple cores have on processor performance
With multiple cores, a processor can divide tasks into smaller chunks and execute them simultaneously across multiple cores. This is known as parallel processing.
This will allow instructions to be carried out faster than with a single core processor
What effect does cache memory have on processor performance
Cache is high speed memory fitted close to the processor,
It can be accessed faster than main memory
This means the speed of retrieving data instructions will be greatly increased and time taken to fetch data will reduce improving performance
What effect does clock speed have on processor performance
refers to the number of cycles a CPU can perform per second,
A higher clock speed means the CPU can process more instructions per second.
resulting in quicker execution of tasks and programs.
What effect does word length have on processor performance
performance improves with greater word length,
Using a 64 bit word length with a 64 bit bus will allow 64 bits of data to be handled in one clock pulse
what is meant by word length
represents the size of the data units the CPU can work with at once,
has a direct effect on the processor’s efficiency and the amount of data it can handle in a single cycle.
What effect does address bus width have on processor performance
Affects the amount of memory that can be read from or written to
When the address bus width increases, the processor can access and work with larger amounts of data stored in memory
What effect does data bus width have on processor performance
data bus width directly affects how much data can be carried in one fetch operation
Increased data bus width means more data can be carried in one fetch operation, allowing the processor to work faster
Explain the need for secondary storage in a computer system
Avoid having to re-enter programs and data for processing by storing a permanent copy.
operation of the barcode reader (6)
Operation:
Scans the barcode using visible red light
Light sensor measures reflected light,
white areas reflect more than
black creating a analogue waveform of the bar code
analogue wave is converted into digital data
interpreted by computer to identify product data
Check digit on the end of barcode is used to ensure bar code validity
What information do barcode lines provide (3)
Country of manufacturer
Name of manufacturer
Product code
operation of digital camera (4)
Operation:
Picture is taken image strikes the camera sensor
Sensor records the amount of light received and converts into a digital value
Image sensor records in RGB format so all other colours can be created within the image
Picture is stored as image file on memory card
Once an image has been imported to the computer which improvements can a image editing software make (4)
Cropping or removing of unwanted parts of the image
Changing resolution
Modifying brightness
red eye removal
How can pictures taken using a digital camera be transferred to a computer
Connecting the camera to computer via usb port
Plugging the camera memory card into the computers card reader
operation of the laser printer (5)
Operation:
Operate one page at a time, files that require printing are sent to the laser printer using a page description language
Printer processes the file and creates a bitmap pattern for the page
Printer laser beam scans along and across the drum inside the printer creating the same pattern as the page
this builds up a pattern of static electricity which attracts toner onto the page
Toner is then fused onto paper by heat and pressure
Advantages of laser printers
Print speed
High quality dry page output
What is a RFID
Radio Frequency Identification Tags,
fixed to products which contain information similar to a barcode
characteristics, operation and purposes of the RFID
Operation:
RFID tags have an antenna that is used to communicate with RFID reader
RFID reader transmits a radio signal which is received by the tag and a programmed information code is returned to the reader
This code is then decoded and translated into digital data that is interpreted by the to computer to identify information received.
How can RFID tags be used for security
Prevents theft as an unpaid item will set off an alarm when removed from store
Advantages of using an RFID reader vs Barcode
RFID scanners can read multiple codes at once, which can help streamline operations.
RFID systems are much more efficient for scanning a large number of items but can be more expensive and require more setup than barcodes.
Disadvantages of using an RFID reader
RFID range is reduced where the tag does not have its own power source
principles of
operation of the hard disk
Drive consists of a number of metal disks which have been coated with a special magnetic material
Disks are mounted on a spindle and rotate at high speeds
A series of read/write heads move across the disk surface together to access or store the data on the disk
Hard disk is mounted in a sealed unit and connected to the power supply inside the computer
Advantages of using a hard disk drive
High data transfer rate
High storage capacity
Cheaper than SSD
Disadvantages of Hard disk
Disk is fixed inside computer, making it difficult to transfer data to another computer
Fragile
principles of
operation of the optical disk
Optical disk is a plastic disc with a mirrored surface
Binary data is burned or pressed onto the surface of the disk as series of pits and lands
pits have a binary value of 0 and lands a binary value of 1
laser beams are used to read the data stored on disk, since pits and lands reflect light differently, this is then decoded into original binary
Advantages of optical disks
Portable
cheap to produce
compatible with cd or dvd
Disadvantages of optical disks
scratching surface can render it inoperative
less storage capacity than a hard disk
slower access time than hard disk or ssd
main characteristics, purposes,
suitability and understand the principles of
operation of the solid-state-disk
NAND flash memory + a controller that
manages pages, blocks and complexities of
writing.
Based on floating gate transistors that
trap and store charge.
no moving parts, no noise, low power expensive
SSD vs Hard Disk
SSD perform faster than hard drives as there are no moving parts
read/write data faster
SSD significantly more expensive than Hard disks and ssd tend to be smaller capacity.
What is meant by NAND flash memory
The term NAND comes from the logic gate that is used to design the memory cells
is a type of non-volatile storage that retains data even when power is turned off.
Describe why fragmentation of files occurs on a hard disk drive
files are saved sequentially
when a new or existing file is saved it may be too big to be stored in the current / next available segment
so the file is broken into multiple parts / fragmented
which are saved in the next available segments
