The document discusses the main components of a computer's central processing unit (CPU). It describes the CPU as containing a control unit that controls the flow of data and instructions, an arithmetic logic unit that performs calculations and logical operations, and various registers for temporary storage of data and instructions. It then provides further details on the control unit, arithmetic logic unit, and different types of registers that make up the CPU.

1. Course Title & Code
CSE-100
Introduction to Computer Systems Sessional

2. COMPUTER HARDWARE
CPU

3. CPU (Central processing unit)

4. Definition
A central processing unit is the electronic circuitry within a computer that
caries out the instructions of a computer program by performing the basic
arithmetic, logical, control and input/output operations specified by the
instructions.

5. COMPONENTS OF CPU
CONTROL UNIT(CU)
ARITHEMATIC LOGIC UNIT (AU)
A NUMBER OF REGISTERS

6. How CPU Works

7. CONTROL UNIT (CU)
 Control Unit controls operations of other parts of CPU as well as all parts of
computer by sending a control signal control sequence of instruction to be
executed control flow of data among all parts of computer interpret instructions
regulate timing of processor send control single to and receive control single
from peripheral devices

8. ARITHMETIC AND LOGIC UNIT (ALU)
 Arithmetic and Logic Unit consists of a complicated set of logic circuit and
accumulator. It is mainly responsible for : Calculation Logical comparison
and Decision

9. REGI STERS
 The term is often used to refer only to the group of registers that can be directly
indexed for input or output of an instruction, as defined by the instruction set.
More properly, these are called the “architected registers“. For instance, the x86
instruction set defines a set of eight 32-bit registers, but a CPU that implements
the X86 instruction set will contain many more hardware registers than just these
eight.

10. There are several other classes of registers:
 (a) Accumulator: It is most frequently used register used to store data taken from
memory. Its number varies from microprocessor to microprocessor.
 (b) General Purpose registers: General purpose registers are used to store data
and intermediate results during program execution. Its contents can be accessed
through assembly programming.
 (c) Special purpose Registers: Users do not access these registers. These are
used by computer system at the time of program execution. Some types of special
purpose registers are given below:

11. Random Access Memory (RAM)
 RAM (random access memory) is the place in a computing device where the
operating system (OS), application programs and data in current use are kept so
they can be quickly reached by the device's processor.

12. Cache Memory
 Cache memory, also called CPU memory, is random access memory (RAM) that a
computer microprocessor can access more quickly than it can access regular
RAM. This memory is typically integrated directly with the CPU chip or placed
on a separate chip that has a separate bus interconnect with the CPU.

13. Expansion Bus
 An expansion bus is an input/output pathway from the CPU to peripheral devices
and it is typically made up of a series of slots on the motherboard. Expansion
boards (cards) plug into the bus.

14. Motherboard

15. Definition
 A motherboard is the physical arrangement in a computer that contains the
computer's basic circuitry and components. On the typical motherboard, the
circuitry is imprinted or affixed to the surface of a firm planar surface and usually
manufactured in a single step. The computer components included in the
motherboard are: The microprocessor (Optionally) coprocessors Memory BIOS
Expansion slots Interconnecting circuitry Additional components can be added to
a motherboard through its expansion slots.

16. MICROPROCESSOR

17. Definition
 A microprocessor is a computer processor on a microchip. It's sometimes called a
logic chip. It is the "engine" that goes into motion when you turn the computer on.
A microprocessor is designed to perform arithmetic and logic operations that
make use of small number-holding areas called registers. Typical microprocessor
operations include adding, subtracting, comparing two numbers, and fetching
numbers from one area to another.

18. BIOS (basic input/output system)
 BIOS is the program a personal computer's microprocessor uses to get the
computer system started after you turn it on. It also manages data flow between
the computer's operating system and attached devices such as the hard disk, video
adapter, keyboard, mouse and printer.