4.7 (every spec point covered) Flashcards
(83 cards)
1
Q
What is the role of processor (3)
A
- execute instructions
- performs calculations
- manages data central to operation of computer
2
Q
Where does the address bus send and receive data from (2)
A
Uni directional bus from processor to I/O or memory
3
Q
Where does the data bus send and receive data from (2)
A
Send: CPU, Memory and I/O
Receive: CPU, Memory and I/O
bidirectional
4
Q
Where does the control bus send and receive data from
A
Send: CPU, Memory, I/O
Receive, CPU, Memory, I/O
5
Q
what sort of information does the control bus carry (3)
A
Carries control signals from cpu to other components
Singnals refer to the current ongoing operation
eg. Memory read/write, interrupt
6
Q
What is the role of the main memory (RAM)
A
Main memory holds the data and instructions that the processor needs to access quickly during program execution
Is volatile
7
Q
Role of the io controllers
A
facilitating communication between the CPU and various input/output devices, such as peripherals.
8
Q
What are the three types of bus found within the cpu?
A
address buss, data bus, control bus
9
Q
What is the role of the address bus(3)
A
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.
10
Q
What is the role of the data bus
A
the pathway through which data travels within a computer system
11
Q
What determines the load capacity of the data bus
A
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
12
Q
What is the function of the control bus
A
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.
13
Q
Explain the von neumann architecure (3)
A
- 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.
14
Q
what is the disadvantage of the von Neumann architecture (1)
A
Often leads to von Neumann bottle neck
15
Q
Where is the Harvard architecture system typical used
A
Embedded systems such as digital signal processing
16
Q
Where is the Von Neumann system typically used
A
Typically used in general purpose computing systems
17
Q
Explain the harvard architecture system (4)
A
- instructions and data are stored in separate memory units
- separate buses for instructions and data
- reading and writing data can be done at the same time as fetching.
- CPU can fetch data and instructions simultaneously
18
Q
why is the Harvard architecture system typically faster. (2)
A
because it uses separate memory and buses for instructions and data. This structural difference allows the system to:
carry out parallel processing
19
Q
What is addressable memory (2)
A
Memory where each individual location has a unique numerical address.
CPU uses these address to fetch/store data.
20
Q
What is the stored program concept (3)
A
The idea that:
machine code instructions and data are stored in
main memory
instructions are fetched from memory and executed serially
CPU fetches an instruction, decodes it and then executes it.
21
Q
What is cache memory
A
Memory that can be accessed very quickly located near the processor
22
Q
How does increasing amount of cache memory improve performance of a processor.
A
- 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
23
Q
Describe the role of the control unit (3)
A
- Controls fetch execute cycle
- Synchronise operation of processor
- Control Transfer of data between registers
24
Q
What are registers (2)
A
small, high-speed storage locations within the CPU
used for storing and processing data and instructions during computation.
25
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
26
Explain the fetch part of the Fetch-Decode Execute cycle (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 from MAR to main memory
Control unit sends memory read signal via control bus
Instructions at the memory address are sent along the data bus to the MDR
instruction in MDR is copied into CIR
Program counter is incremented to point to the next instruction
27
describe the decode part of the fetch decode execute cycle (2):
Control unit decodes instruction held in CIR
Decides what needs to happen next ( ALU operation, memory access r/w,)
28
Describe the execute part of the fetch decode execute cycle (3):
The instruction is executed
If its an arithmetic/logic operation - done by ALU
if its a memory operation, address/data may be sent via buses again
29
What is the role and operation of the ALU (2)
Part of cpu:
Performs arithmetic
performs logical operations (AND, OR, NOT etc.)
30
What is the role and operation of the Control unit within the fetch execute cycle (2)
Directs the operation of the processor.
Tells the memory, ALU , I/O devices how to respond to instructions
31
What is the role and operation of the general purpose registers
Can be used to hold data and instructions temporarily during instruction execution
small fast storage locations
32
What is the role and operation of the dedicated registers
Used by processors to carry out a specific role
33
What is the role and operation of the program counter
Register that holds the address of the next instruction being fetched
34
What is the role and operation of the current instruction register
Used to store the instruction that is to be decoded and executed
35
What is the role and operation of the memory address register
Holds the memory address of the memory location to r/w from.
36
What is the role and operation of the memory buffer register
Holds the instruction from the MAR and the associated data
37
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
38
What is meant by the term ‘processor instruction set’
The set of machine code instructions that a particular type of processor can understand
defined by CPU designer and depends on CPU architecture,
39
What is meant by opcode (2)
specifies the operation to be performed + the addressing mode
40
What is meant by operand
Specifies the data/memory address involved in the calculation
41
Describe the makeup of instructions
Consists of opcode and operand
42
What is immediate addressing
When the operand contains the actual data to be used
43
What is direct addressing
Operand contains memory address where data is stored instead of the actual data itself
44
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
45
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
46
What effect does multiple cores have on processor performance (4)
With multiple cores, a processor can divide tasks into smaller chunks and execute them simultaneously across multiple cores.
multiple fetch decode execute cycles can happen at once.
This is known as parallel processing.
This will allow instructions to be carried out faster than with a single core processor
47
What effect does cache memory have on processor performance (5):
Cache is high speed memory fitted close to the processor,
It can be accessed faster than main memory
larger cache memory means less accessing the slower main memory
This means the speed of retrieving data instructions will be greatly increased and time taken to fetch data will reduce
less time spent idle by CPU, more instructions completed per second.
48
What effect does clock speed have on processor performance (4)
refers to the number of cycles a CPU can perform per second,
each cycle allows cpu to perform one basic action like fetching one instruction
A higher clock speed means the CPU can process more instructions per second.
resulting in quicker execution of tasks and programs.
49
what is the risk of increasing clock speed
Overheating and increased power consumption
50
What effect does word length have on processor performance (5)
word length refers the the number of bits a CPU can process as s single unit at once.
a larger word length allows CPU to process larger amount of data per cycle
Using a 64 bit word length with a 64 bit bus will allow 64 bits of data to be handled in one clock pulse
larger word length means more data can be manipulated per instruction.
fewer cycles required to process large data sets,
51
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.
52
What effect does address bus width have on processor performance (4)
address bus - carries memory addresses from CPU to ram
wider width allows CPU to address more memory locations directly.
When the address bus width increases, the processor can access and work with larger amounts of data stored in memory
speeding up overall program execution
53
What effect does data bus width have on processor performance (4)
a wider data bus means a wider data bus can transfer more bits of data simultaneously.
wider data bus, faster transfer of data to and from CPU.
speeds up fetch part of fetch execute cycle.
increases number of instructions that can be completed per second.
54
Explain the need for secondary storage in a computer system (2)
Avoid having to re-enter programs and data for processing by storing a permanent copy.
since ram is volatile and data is lost when power is turned off.
55
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
56
What information do barcode lines provide (3)
Country of manufacturer
Name of manufacturer
Product code
57
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
58
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
59
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
60
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
61
Advantages of laser printers (2)
Print speed
High quality dry page output
62
What is a RFID (2)
Radio Frequency Identification Tags,
fixed to products which contain information similar to a barcode
63
operation of RFID (3):
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 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.
64
How can RFID tags be used for security (1)
Prevents theft as an unpaid item will set off an alarm when removed from store
65
Advantages of using an RFID reader vs Barcode (2)
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.
66
Disadvantages of using an RFID reader (3)
RFID range is reduced where the tag does not have its own power source
requires more setup
more expensive
67
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
68
Advantages of using a hard disk drive (3)
High data transfer rate
High storage capacity
Cheaper than SSD
69
Disadvantages of Hard disk (3)
Disk is fixed inside computer, making it difficult to transfer data to another computer
Fragile, prone to mechanical failure due to moving parts
slower access speed than ssd
70
principles of
operation of the optical disk (5)
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
71
Advantages of optical disks (3)
Portable
cheap to produce
compatible with cd or dvd
72
Disadvantages of optical disks (3)
scratching surface can render it inoperative
less storage capacity than a hard disk
slower access time than hard disk or ssd
73
Operation of SSD (3)
NAND flash memory
+ a controller that
manages pages, blocks and complexities of
writing.
Based on floating gate transistors that
trap and store charge.
74
advantages of SSD's (5)
no moving parts, no noise, low power usage, faster access speeds, durable no moving parts
75
disadvantages of ssd(2)
expensive, typically lower capacity than hdd worse for bulk storage
76
SSD vs Hard Disk (4)
HDD:
bigger capacity
cheaper- lower cost per gb
SSD:
Faster access speeds
more durable no moving parts
77
What is meant by NAND flash memory (2)
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.
78
Describe why fragmentation of files occurs on a hard disk drive (4)
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
79
which buses are bidirectional (1)
Data bus or control bus
80
which bus is unidirectional (1)
address bus
81
What is a bus (1)
a shared communication medium that transfers data between components.
82
what is the role of the clock within the CPU.(1)
Emits pulses that synchronise the CPU's operations
83
what is the role of the accumulator (1)
Temporary store for arithmetic and logic results
