1.1 The characteristics of contemporary processors, input, output and storage devices Flashcards
What does the ALU do?
It completes all the arithmetical and logical operations
What is the CU?
A part of the processor which directs operations inside the CPU
What are registers?
Small memory cells that operate at high speeds
Where do all the arithmetic, logic, or shift operations occur?
In registers
What does the PC do?
The PC holds the address of the next instruction
In which part of the CPU do all calculations take place?
The ALU
Where are intermediate arithmetic and logic results stored?
In the ACC
What does the MAR do?
Holds the address of a location that is to be read from or written to
What does the MDR do?
Temporarily stores the data that has just been read from or the data needs to be written
What does the CIR do?
Holds the current instruction divided up into opcode and operand
What is a bus?
A set of parallel wires connecting two or more components together
What is the system bus?
The collection of the data bus, address bus, and control bus is called the system bus
What is the width of a bus?
The number of parallel wires it has
What is the data bus?
A bidirectional bus used to transport data and instructions between components
What is the control bus?
The bi-directional bus used to transmit control signals between internal and external components
What is the address bus used for?
Used to transmit the memory address specifying where data is to be sent from or retrieved from
What does adding a wire to the address bus do to the number of addressable locations?
It doubles the number of addressable locations
What does the Bus Request indicate?
Indicated a device is requesting access to the data bus
What does Bus Grant indicate?
Indicates the CPU has granted access to the data bus
What does memory write do?
Causes the data on the data bus to be written into the addressed location
What does memory read do?
Causes the data from the addressed location to be placed onto the data bus
What does the interrupt request control signal indicate?
Indicates that a device is requesting access to the CPU
What is the clock control signal used for?
It is used to synchronize instructions
What is opcode?
Opcode is used to determine the type of instruction and what hardware to use to execute it
What is the operand?
The operand is the address of where the operation is performed
What occurs during the fetch phase?
- The address from the PC is copied to the MAR
- Instruction held at that address is copied to the MDR by the data bus, simultaneously the contents of the PC is incremented by 1
- The value of the MDR is copied to the CIR
What occurs during the decode phase?
The contents of the CIR is split into operand and opcode
What occurs during the execute phase?
The opcode is executed on the data
What is the clock speed?
The number of clock cycles completed per second
What is cache memory?
Cache memory is the CPU’s onboard memory which can be accesses a lot faster than main memory
What is Von Neumann architecture?
Architecture in which there is a single shared memory and shared data bus for both data and instructions
What is Harvard architecture?
Architecture in which there is two separate memory and data buses for data and instructions
What is contemporary processing?
Processing in which Von Neumann architecture is used for main memory. Cache uses Harvard architecture, divided into instructions, cache and data cache
What does RISC mean?
Reduced Instruction Set Computer
What does CISC mean?
Complex Instruction Set Computer
What are the properties of RISC?
- Small instruction set
- Each instruction is one line of machine code
- Used in everyday devices
What are the properties of CISC?
- A large instruction set
- Instructions are built into hardware
- Used in embedded systems and microprocessors
What are the benefits of RISC processors?
Pipelining is possible since each instruction takes one clock cycle
What are the benefits of CISC processors?
- Compilers have to do less work
- They require less RAM since instructions are smaller
What are multi-core systems?
Systems where there are multiple cores that separate fetch-execute cycles
What are parallel systems?
Systems where multiple instructions can be completed at any given time, doesn’t require multiple cores, it can use threading and pipelining instead
Give two types of magnetic storage
- Hard Disk Drive
- Floppy Disk
- Magnetic Tape
Give three examples of input devices
- Keyboard
- Mouse
- Microphone
- Webcam
- Touchpad
- Barcode reader
- Magnetic Stripe Reader
Give an example of a device which is used for both input and output
Touchscreen
What name is given to the areas on a CD’s surface which have been burned into grooves by a laser?
Pits
Give three examples of output devices
- Speaker
- Monitor
- Printer
- Projector
Which has the highest typical storage capacity: CD, DVD or Blu-Ray?
Blu-Ray
In a HDD what is mounted at the end of the actuating arm?
Read/write head
Which storage device has typical capacities in the range 500GB-5TB?
HDD
Give 2 disadvantages of SSDs
- High cost per GB
- Limited lifespan
How is information stored in flash memory?
Information is stored in blocks which are then combined to form pages
Which two types of logic gates are used in flash storage?
NAND and NOR
Give 3 advantages of SSDs
High transfer speeds
Lightweight
No moving parts
Give 2 disadvantages of SSDs
- Expensive
- Limited read/writes
What is ROM?
- Small piece of read-only memory
- Non volatile
- Contains very first instructions for the computer (bootstrap)
What is RAM?
- Temporary storage of instructions and data
- Holds information being executed by the processor
- Volatile
- Much faster than the hard disk
What is virtual storage?
- The concept of storing and receiving data over the internet in the cloud instead of a local storage device
What are the advantages of Cloud storage?
- Data can be accessed at any time, from any device as long as there is internet access
- Data can be easily shared without the need for removable media transfer
- Easy collaboration
- Storage considered to be ‘limitless’ from the user’s point of view
What are the disadvantages of cloud storage?
- Can become quite expensive
- If connectivity is low, access times can be slow
- No internet connection = no access to your files
What can virtual storage also refer to?
- The abstraction or separation of logical storage from physical storage
