Processor in Computer Organization

 Processor  

• ·       In computer organizations, the processor is the Central Processing Unit (CPU).
• ·       The main component of a computer that executes instructions and performs calculations. 
• ·       Computer's "brain" that runs the operating system and applications.
• ·       CPU is inserted into a CPU socket on the motherboard, covered by a heat sink to absorb heat and keep the CPU cool and functioning smoothly.

Introduction to the Processor

  1. Definition and Role:

   - works as the "brain" of the computer.

Execute program instructions by performing basic arithmetic, logic, control, and input/output operations specified by the instructions.

  2. Components of a Processor:

   Control Unit (CU): This unit directs the operation of the processor. It controls the computer's memory, arithmetic/logic unit, and input and output devices and responds to the instructions sent to the processor.

   - Arithmetic Logic Unit (ALU): Performs arithmetic and logic operations. Perform calculations and decision-making processes.

   - Registers: Small, fast storage locations within the CPU that temporarily hold data and instructions that the CPU is currently processing.

   - Cache: A smaller in size, faster type of volatile memory that provides high-speed data access to the processor and improves overall speed and performance.

  3. Processor Architecture:

   - Instruction Set Architecture (ISA): The set of instructions that a CPU can execute.

   - Microarchitecture: a CPU’s core components, defining how it implements the ISA. Different CPUs with the same ISA can have different microarchitectures.

  4. Processing Techniques:

   - Pipelining: A technique where multiple instruction phases (fetch, decode, execute) are overlapped to improve performance.

   - Superscalar Execution: The ability of a processor to execute more than one instruction per clock cycle by dispatching multiple instructions to appropriate functional units in the processor.

   - Multicore Processing: Incorporating multiple processor cores into a single CPU to handle parallel processing and improve multitasking capabilities.

  5. Clock Speed:

   - Measured in gigahertz (GHz), the clock speed determines how many cycles a CPU can perform per second. Higher clock speeds generally mean faster processing.

  6. Performance Factors:

   - Instruction Per Cycle (IPC): The number of instructions a CPU can execute in one clock cycle.

   - Thermal Design Power (TDP): The maximum amount of heat a processor is expected to generate under normal conditions, affecting cooling requirements and overall performance.

  7. Advancements in Processor Technology:

   - Hyper-Threading: A technology used to improve parallelization of computations (performing multiple tasks simultaneously) by allowing a single CPU core to act like two separate cores to the operating system and application programs.

   - Integrated Graphics: Some processors include a GPU on the same chip to handle graphics processing, reducing the need for a separate graphics card.

 

The primary functions of a processor–

1. Fetch – 
   The CPU fetches the address of the instruction executed from the program counter in the memory and performs the instruction.
   
   
2. Decode – 
   The instruction is converted into binary code. The process of conversion is known as decoding.
    
3. Execute – 
   Performing the required task specified in the instruction is known as execution. 

 

4. Write back – 
   After performing the instruction the CPU stores the result in the memory that process is known as a store or write back.

Components of CPU

Generally, a CPU has three components:

• ALU (Arithmetic Logic Unit)
• Control Unit
• Memory or Storage Unit

 

1.   ALU (arithmetic logic unit):

• Performs arithmetic and logical operations.
• arithmetic operationà addition, subtraction, multiplication, division.
• Logical operations à comparisons.
• Primary logical operations à Data selection, comparison, and merging are the.
• More than one ALU may be present in a CPU.
• Also be used to keep track of timers that assist in running the computer.
• The ALU consists of two main subsections: the Arithmetic Section and the Logic Section.

• Arithmetic Section conducts mathematical operationsà including addition, subtraction, multiplication, and division.  
• Logic Section conducts logical operationsà choosing or removing certain data elements or fields, comparing values to identify connections (such as equal, greater than, or less than), and merging or combining data by logical principlesà used for Decision-making, data filtering, and data processing tasks.

Control Unit:

• ·       Responsible for the overall performance of a computer system.
• ·       Controls and coordinates the functioning of all parts of the computer.
• ·       A circuit in the control unità uses electrical signals to instruct the computer system. à takes instructions from memoryà decodes and executes these instructions.
• maintain and regulate the flow of information across the processor.
• Work as a traffic controllerà information and instructions transferred among the various elements of the computer system.
• It manages the order of instructions and synchronizes the activities of various units within the CPU.

Memory or Storage Unit

• Save and maintain instructions, data, and intermediate outcomes.
• Also called an internal storage unit, main memory, primary storage, or Random-access reminiscence (RAM).
• directly affects the computer's speed, power, and normal performance.

two types of memory: primary and secondary.

Primary memory

• called RAMà main memory of a computerà closely collaborates with the CPU to quickly store and retrieve data. 
• access information randomly, which means it can retrieve any piece of data without going through everything in order. 
• acts as a momentary workspace where the computer stores the information and applications it is now utilizing. 
• RAM is a volatile memory, so anything saved inside is lost when the machine is switched off. How many programs can run simultaneously and how much data can be processed simultaneously depends on the RAM capacity. 

• The clock speed of a processor, often known as the CPU clock rate, is an important component. The clock speed of a CPU or a processor refers to the number of instructions it can process in a second. It is measured in gigahertz. For example, a CPU with a clock speed of 4.0 GHz means it can process 4 billion instructions in a second.  

CPUs are mostly manufactured by Intel and AMD, each of which manufactures its own types of CPUs. In modern times, there are lots of CPU types in the market. Some of the basic types of CPUs are described below:

• Single-Core CPUs
• Dual-Core CPUs
• Quad-Core CPUs
• Hexa-Core CPUs
• Octa-Core CPUs
• Multi-Core CPUs

The processor plays a significant role in the following important aspects of a computer system.

• Performance – 
  The processor is probably the most single determinant of system performance in the PC. While other components such as memory, hard disks, display adapters, etc. play key roles in determining performance, the processor’s capabilities have the greatest impact on the performance of a system. The core and clock speed of a processor determines the speed of a PC. They tell us how much information can be processed in how much time. In fact, the other devices present in the system play their roles to allow the processor to reach its full potential.
   
• Software support – 
  A newer, faster processor enables the use of the latest software, which provides support for running heavy software on our PC and saves our time by working efficiently and with faster processing. 
   
• Reliability and Stability – 
  The quality of the processor is one factor that determines how reliably the system will run While most processors are dependable some processors or not. This also depends to some extent on the age of the processor, energy consumption of the processor, motherboard, power supply voltages, cooling, etc.
   
• Energy consumption and cooling – 
  Originally processors consumed relatively little power compared to other system devices. However, some processors consume a great deal of power. Power consumption has an impact on everything from cooling device selection to overall system reliability.
   
• Motherboard Support – 
  The processor is the system is a major determining factor in the selection of chipset and the type of motherboard. The motherboard in turn dictates many facets of the system’s capabilities and performance.

 

====================================================