Central Processing Unit
Introduction
The Central Processing Unit (CPU) is the brain of a computer. It performs all processing operations, executes instructions, and controls other hardware components. The CPU's speed and efficiency determine a computer’s overall performance.
Components of CPU
1. Arithmetic Logic Unit (ALU)
- Performs arithmetic operations (addition, subtraction, multiplication, division).
- Executes logical operations (AND, OR, NOT, comparisons).
2. Control Unit (CU)
- Directs the flow of data and instructions within the CPU.
- Fetches, decodes, and executes instructions from memory.
- Controls communication between the CPU and other components.
3. Memory Unit - Registers
- Small, high-speed memory units within the CPU.
- Temporarily store instructions, data, and addresses.
Types of registers:
- Accumulator (AC) – Stores results of calculations.
- Program Counter (PC) – Holds the address of the next instruction.
- Instruction Register (IR) – Stores the current instruction being executed.
Working of CPU (Instruction Cycle - Fetch, Decode, Execute)
- Fetch – The CPU retrieves an instruction from memory.
- Decode – The instruction is interpreted by the Control Unit.
- Execute – The ALU performs calculations or logic operations.
- Store – The result is saved in a register or sent to an output device.
Types of CPU Architecture
CISC (Complex Instruction Set Computing)
- Supports many complex instructions.
- Examples: Intel x86, AMD processors.
RISC (Reduced Instruction Set Computing)
- Uses simpler, faster instructions.
- Examples: ARM processors (used in smartphones, tablets).
CPU Performance Factors
- Clock Speed (GHz) – Determines how many instructions a CPU can process per second.
- Number of Cores – More cores allow multiple tasks to run simultaneously.
- Cache Memory – High-speed memory that stores frequently used data for quick access.
- Threading & Multitasking – Enables better processing of multiple tasks.
Popular CPU Brands
- Intel – Core i3, i5, i7, i9, Xeon.
- AMD – Ryzen 3, 5, 7, 9, Threadripper.
- Apple – M1, M2 processors.
- Qualcomm – Snapdragon (used in mobile devices).
Qus. 1 : The brain of any computer system is
- Control Unit
- Arithmetic Logic Unit
- Central Processing Unit
- Storage Unit
- Arithmetic and Logic Unit
- Control Unit
- Both of above
- None of above
- Clock speed (GHz)
- MIPS (Million Instructions Per Second)
- FLOPS (Floating Point Operations Per Second)
- All of the above
- To decode program instructions
- To transfer data to primary storage
- To perform logical operations
- To store program instructions
- RAM
- secondary storage
- main memory
- the CPU
- Processor
- RAM
- ROM
- Hard Drive
- CU
- ALU
- PROCESSOR
- All of these
- ALU
- CU
- Memory
- Register
- Control unit
- Cache unit
- Calculating unit
- Communication unit
- Central Processing Unit
- Memory unit
- I/O unit
- Operating unit
- Control Unit and ALU
- Operating System and Application
- ROM and Main Memory
- Hard Disk and Floppy Drive
- Read Access Memory
- Random Access Memory
- Red Access Memory
- None of the above
- CPU, I/O Devices
- I/O Devices, CPU
- Timer, I/O Devices
- CPU, ALU
- Primary memory
- Control unit
- Cache memory
- External memory
- The size of the CPU
- The number instructions the CPU can execute per second
- The amount of memory in the CPU
- The data transfer rate of the CPU
- Bits
- Bytes
- Hertz (Hz)
- Cycles
- A-1, B-2, C-3, D-4
- A-3, B-4, C-2, D-1
- A-2, B-3, C-4, D-1
- A-4, B-1, C-3, D-2