Characteristics of Contemporary Processors

What does the arithmetic and logic unit do?

completes all arithmetic and logic operations

What is the control unit?

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 program counter (PC) do?

holds the address of the next instruction

In which part of the CPU do all calculations take place?

the arithmetic logic unit (ALU)

Where are intermediate arithemtic and logic results stored?

accumulator

What does the memory address register do?

holds the address of a location that is to be read from or written to

What does the memory data register do?

temporarily stores data that has just been read from or data that needs to be written

What does the current instruction register 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 a system bus?

the collection of the data, address and control 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?

a bi-direction bus used to transmit control signals betweeen internal and external components

What is the address bus used for?

to transmit the memory address, specifying where data is to be read from or written to

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?

a device is requesting access to the data bus

What does bus grant indicate?

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?

a device is requesting access to the CPU

What is the clock control signal used for?

to synchronise instructions

What is assembly language?

a programming language where mnemonics are used to represent instructions

What is opcode used for?

to determine the type of instruction and what hardware to use to excecute it

What is the operand?

the address of where the operation is performed

What occurs during the fetch stage? (4 things)

1. address from the program counter is copied to the memory address register 2. the instruction held at that address is copied to the memory data register 3. simultaneously the contents of the program counter is increased by 1 4. the value of the memory data register is copied to the current instruction register

What occurs during the decode stage?

the contents of the CIR is split into opcode and operand

What occurs during the excecute 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?

the CPU's onboard memory which can be accessed a lot faster than main memory

What is von neumann architecture?

architecture where there is a shared memory and data bus for both data and instructions

What is harvard architecture?

architecture where there is a seperate memory and data buses for data and instructions

What is contemporary processing? (2 things)

1. processing where von neumann architecture is used for main memory 2. cache uses harvard architecture, divided into instruction cache and data cache

What does RISC stand for?

reduced instruction set computer

What does CISC stand for?

complex instruction set computer

What is CISC?

a large instruction set

Where are CISC instructions built into?

hardware

What 2 places is CISC used?

embedded systems microprocessors

What is RISC?

a small instruction set

What is each instruction in RISC the same as?

one line of machine code

Where is RISC used?

everyday devices

What is the benefit of RISC processors?

pipelining is possible since each instruction takes one clock cycle

Whare are the 2 benefits of using CISC processors?

1. compilers have to do less work 2. they require less RAM, since instructions are smaller

What is a graphics processing unit (GPU)?

a co-processor made up of lots of independent parallel processors

Whare are 2 uses of GPU's?

1. image processing 2. machine learning

What are multi-core systems?

systems where there are multiple cores that seperate fetch-execute cycles

What are parallel systems? (2 things)

1. systems where multipe instructions can be completed at any given time 2. they dont require multiple cores and can use threading and pipelining instead

What are 3 types of magnetic storage?

1. hard disk drive 2. floppy disk 3. magnetic tape

What are 3 examples of input devices?

1. keyboard 2. mouse 3. microphone

What is 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

What does CD stand for?

compact disk

What are 3 examples of output devices?

1. speaker 2. monitor 3. printer

What is the order of of capacity for CD, DVD and Blue-ray, in order of increasing capacity?

CD DVD Blu-Ray

In a hard disk drive, what is moutned at the end of the actuating arm?

read / write head

What storage device has a typical capacity in the range 500GB - 5TB?

hard disk drive

What are 2 disadvantages of SSDs?

1. high cost per GB 2. limited number of read/write cycles

What does ROM stand for?

read only memory

What is the structure where information is stored in flash memory?

information is stored in blocks, which are combined to form pages

What is meant by the term non-volatile in storage?

information is not lost when power is lost

What 2 type of logic gates are used in flash storage?

NAND and NOR

What are 3 advantasges of SSD's?

1. higher transfer speeds 2. lightweight 3. no moving parts

Is ROM volatile or non-volatile?

non-volatile

Which form of storage devices uses silicon semiconductores to store information?

flash

What are 3 disadvantages of CD's?

1. easily damaged by scratches 2. relatively low capacities 3. relatively slow transfer speeds