Characteristics of contemporary Processors, Input, Output and storage devices

Aatika Seedat
Mind Map by Aatika Seedat, updated more than 1 year ago


1.1 Characteristics of contemporary processors, Input, Output and storage devices. A-level computer Science OCR.

Resource summary

Characteristics of contemporary Processors, Input, Output and storage devices
1 The arithmetic and logic unit
1.1 ALU
1.1.1 performs calculations in the CPU
1.1.2 uses binary numbers
1.2 CU
1.2.1 directs operations of the processor
1.2.2 tells components of the CPU how to respond to a program's instruction.
1.3 Responsible for logical decisions and arithmetic in the CPU
2 Registers
2.1 High-speed storage areas within the CPU.
2.2 program counter (PC)
2.2.1 Shows where computer is in it's program sequence
2.2.2 incremented after fetching an instruction.
2.2.3 holds memory address of next instruction to be executed
2.3 Accumulator (ACC)
2.3.1 Results from ALU are stored in accumulator
2.4 Memory Address Register (MAR)
2.4.1 Stores address of data/instruction which needs to be accessed
2.5 Memory Data Register (MDR)
2.5.1 cOntains the data that needs to be stored in the RAM
2.5.2 or stores the data that has been fetched from the RAM.
2.6 Current Instruction Register (CIR)
2.6.1 holds current instructions to be executed
3 Busses
3.1 Data Bus
3.1.1 Transfers data from MDR to RAM and vice versa
3.1.2 Bi-directional
3.2 Address bus
3.2.1 transfers the address of data needed by the CPU from the MAR to the RAM.
3.2.2 One direction
3.3 Control bus
3.3.1 Transfers control signals from CU to Ram and vice versa
3.3.2 Bi-directional
3.4 Transfers data between components in a CPU
4 Fetch decode execute cycle
4.1 1. Fetch
4.1.1 a. the PC sends the address of the next instruction to the MAR
4.1.2 b. The instruction travels along the address bus to the RAM
4.1.3 c. The Control Unit sends signals to the RAM to read the data/ instruction stored in the address from the MAR
4.1.4 d. when the next instruction or data is found, it is transferred along the dat bus to the MDR
4.1.5 e. value or instruction is sent to CIR to decode or execute.
4.2 2. Decode
4.2.1 instructions in CIR are decoded by decode unit in two ways OPCODE- command OPERAND- address or data
4.3 3. Execute
4.3.1 if decoded into instruction, it is executed
4.3.2 if decoded into address it is sent to MAR and FDE CYCLE STARTS AGAIN
5 Factors affecting performance of CPU
5.1 Clock speed
5.1.1 in megahertz (MHz) or gigahertz (GHz)
5.1.2 speed at which the computer can execute instructions.
5.1.3 processors with a higher clock speed can process data and instructions faster
5.1.4 efficiency depends on how much a computer can do with the same number of cycles.
5.2 Number of cores
5.2.1 jobs split between processors
5.2.2 each core can process instructions independently
5.2.3 more cores= more instructions being processed
5.2.4 BUT needs a special OS to manage instructions and cores
5.3 Cache
5.3.1 temporary memory locations for faster access
5.3.2 Saves time when looking for data/instructions
5.3.3 Reading from RAM takes longs having cache saves time
5.3.4 Larger cache improves performance of CPU as instructions will be carried out faster as data can be stored in cache making it easier to access
6 Von neumann, Harvard and contemporary processor architecture
6.1 Von Neumann
6.1.1 Has a single control unit
6.1.2 works sequentially through instructions
6.1.3 instructions and data stored in the same memory
6.2 Harvard
6.2.1 data and instructions stored in separate memories.
6.3 Contemporary processors
6.3.1 Parallel processing. SIMD (Single Instruction Multiple Data) Same operation carried out on multiple data MIMID (Multiple Instruction Multiple Data) Different operations carried out on different data
7 The differences between and uses of CISC and RISC processors
7.1 CISC processors
7.1.1 Complex Instruction Set Computing
7.1.2 Larger range of instructions
7.1.3 Several clock cycles to execute instructions
7.1.4 Needs more power to work
7.1.5 Complicated hardware, simple software
7.2 RISC processors
7.2.1 Reduced Instruction Set Computing
7.2.2 Simple instruction set
7.2.3 less power and costs less to produce
7.2.4 Single clock cycles, so can use pipelining
7.2.5 More advanced compilers
7.2.6 Simple hardware, complicated software
8 Multi-core and parallel systems
8.1 Multi-core
8.1.1 Single computer with 2 or more independant processing units carrying out instructions
8.1.2 Multiple instructions run at the same time
8.1.3 On one chip
8.2 Parellel
8.2.1 processing program instructions by diving them among multiple processors
8.2.2 Large problems divided into smaller ones
8.2.3 Results of small tasks combined to produce output
9 Input and Output Devices
9.1 Input devices
9.1.1 Piece of computer hardware used to enter data and control signals into a computer
9.2 Output devices
9.2.1 A piece of computer hardware which allows data to be retrieved from a computer.
10 The uses of magnetic, flash and optical storage
10.1 Magnetic storage
10.1.1 Uses a magnetizable material to store data, changes in magnetic field represents binary. E.g. magnetic tape
10.2 Flash media
10.2.1 can be overwritten. Has no moving parts so can be written to and read from at high speeds, Very duarble
10.3 Optical storage
10.3.1 Using a laser to look at reflections, Pits in the surafce represent 1's or 0's. E.g. CD
11 RAM, ROM and virtual storage
11.1 RAM
11.1.1 Random Access Memory
11.1.2 Stores programs currently being used, Volatile (if power turned off, all will be lost).
11.2 ROM
11.2.1 Read Only Memory
11.2.2 Non-Volatile, cannot be written to, Contains BIOS
11.3 Virtual Storage
11.3.1 Makes computer appear as if it has unlimited memory
11.3.2 Things not being used in RAM moved to hard drive, freeing up space for programs to run
11.3.3 Using more virtual memory slows computer because things stored in hard drive have to be mapped back to real memory
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