1.1 The characteristics of contemporary processors, input, output and storage devices Flashcards
What is the role of the PC (Program Counter)?
Stores the address of the next instruction or data to be fetched
Give the name of the computer architecture that uses the fetch-execute cycle with a single control unit.
Von-Neuman Architecture
Does CISC or RISC processors can process more complex instructions?
CISC processors
What is the role of the MAR (Memory Address Register)?
Stores the address of the instruction or data to be fetched
What is the role of the MDR (Memory Data Register)?
Stores data read from or being written to the RAM
Does CISC or RISC processors complete an instruction in one clock CYCLE?
RISC processors
What does CISC stand for?
complex instruction set computer
What does RISC stand for?
Reduced instruction set computer
What are three types of processing?
Concurrent processing, parallel processing, Multi-core processing
What is the role of the CIR (Current Instruction Register)?
Stores the instruction currently being executed
What is unique about parallel processing?
Different processes can be executed on processors at different or the same time.
What is unique about Multi-core processing?
Different processes can be executed on different processors at different or the same time
What is unique about concurrent processing?
Several processes executed at the same time instead of sequentially.
What is the role of then ACC (Accumulator)?
Stores the result of calculations from ALU (Arithmetic Logic Unit)
What is meant by the term ‘Virtual Memory’ and what is it’s function?
Virtual memory is additional memory used when RAM is full. It acts as secondary storage and is used to store unused programs while the current program being run is replaced in RAM.
What does RAM stand for and what is it’s purpose?
Random Access Memory - Short term volatile memory where currently running instructions and data is stored.
What does ROM stand for and what is it’s purpose?
Read Only Memory - Non-volatile memory which stores data even when the computer is turned off.
What happens during the Fetch section in the FDE cycle?
- The address of the next instruction is copied from the PC to the MAR.
- The instruction held at that address is copied to the MDR. Simultaneously, the content of the PC is incremented so that it holds the address of the next instruction.
- The contents of the MDR are copied to the CIR.
What happens during the Decode section in the FDE cycle?
- The instruction in the CIR is decoded. The instruction is split into opcode and operand. The opcode is used to determine the type of instruction and what hardware to use to execute it. The operand holds either:
the address of the data to be used with operation, which is the copied to the MAR
the actual data to be operated on, which will be copied to the MDR
the data to be operated on may be passed to the ACC
What happens during the Execute section in the FDE cycle?
- The appropriate instructions / opcode is carried out on the operand.
Give an example and name an advantage of magnetic storage.
Floppy disk, Hark disk. Has a high capacity of storage compared to the other storage types.
Give an example and name an advantage of flash storage.
USB flash drive. Flash storages are typically very portable.
