Unit 01
Basic building blocks of Computer System:
In computer architecture, the basic building blocks of a computer system can be broken down into
several key components, each of which plays a crucial role in the functioning of the computer. These
are
Central Processing Unit (CPU): Central processing unit commonly known as
CPU can be referred as an electronic circuitry within a computer that carries out
the instructions given by a computer program by performing the basic arithmetic,
logical, control and input/output (I/O) operations specified by the instructions.
Arithmetic & logical unit (ALU):- Most of all the arithmetic and logical operations
of a computer are executed in the ALU (Arithmetic and Logical Unit) of the processor. It performs
arithmetic operations like addition, subtraction, multiplication, division and also the logical operations
like AND, OR, NOT operations.
Performs arithmetic and logical operations (e.g., addition, subtraction, AND, OR
operations).
Control Unit:- Directs the operation of the processor by interpreting and executing
instructions from the memory.
The control unit is a component of a computer's central processing unit that coordinates
the operation of the processor. It tells the computer's memory, arithmetic/logic unit and input and
output devices how to respond to a program's instructions.
The control unit is also known as the nerve center of a computer system.
Let's us consider an example of addition of two operands by the instruction given as Add LOCA, RO.
This instruction adds the memory location LOCA to the operand in the register RO and places the
sum in the register RO. This instruction internally performs several steps.
Input Unit: Input units are used by the computer to read the data. The most
commonly used input devices are keyboards, mouse, joysticks, trackballs,
microphones, etc.
Output Unit: The primary function of the output unit is to send the processed
results to the user. Output devices display information in a way that the user can
understand.
, Output devices are pieces of equipment that are used to generate information or any
other response processed by the computer. These devices display information that has
been held or generated within a computer.
The most common example of an output device is a monitor.
Storage Unit: The storage unit in computer architecture is responsible for
storing data and instructions that the CPU can access for processing. It can be
broadly classified into two categories based on speed, capacity, and volatility.
Memory:
Primary Memory (RAM): Volatile memory used to store data and
instructions that are currently being used by the CPU.
Cache Memory: Small, very fast memory located close to the CPU to store
frequently used data and instructions for faster access.
Secondary Memory: Non-volatile memory used for long-term data storage
(e.g., hard drives, SSDs).
Bus System: A communication pathway that transfers data between the CPU,
memory, and other peripherals. It includes:
Data Bus: Transfers data.
Address Bus: Specifies memory locations.
Control Bus: Coordinates the activities of the CPU and other
components
General System Architecture:
In Computer Architecture, the General System Architecture is divided into two major classification
units.
Store Program Control Concept
Flynn's Classification of Computers
Store Program Control Concept:-
• The term Stored Program Control Concept refers to the storage of instructions in computer
memory to enable it to perform a variety of tasks in sequence or intermittently.
• The idea was introduced in the late 1040s by John von Neumann who proposed that a
program be electronically stored in the binary-number format in a memory device so that
instructions could be modified by the computer as determined by intermediate computational
results.
, • ENIAC (Electronic Numerical Integrator and Computer) was the first computing system
designed in the early 1940s. It was based on Stored Program Concept in which machine use
memory for processing data.
Stored Program Concept can be further classified in three basic ways:
Von-Neumann Model: Von-Neumann proposed his computer architecture design in 1945
which was later known as Von-Neumann Architecture. It consisted of a Control Unit,
Arithmetic, and Logical Memory Unit (ALU), Registers and Inputs/Outputs.
Von Neumann architecture is based on the stored-program computer concept, where instruction data
and program data are stored in the same memory. This design is still used in most computers
produced today.
A Von Neumann-based computer:
Uses a single processor.
Uses one memory for both instructions and data.
Executes programs following the fetch-decode-execute cycle.
General Purpose System: A general-purpose system typically refers to a computer system
designed to handle a wide range of tasks, with flexible capabilities in terms of processing,
memory management, input/output operations, and more.
Basic building blocks of Computer System:
In computer architecture, the basic building blocks of a computer system can be broken down into
several key components, each of which plays a crucial role in the functioning of the computer. These
are
Central Processing Unit (CPU): Central processing unit commonly known as
CPU can be referred as an electronic circuitry within a computer that carries out
the instructions given by a computer program by performing the basic arithmetic,
logical, control and input/output (I/O) operations specified by the instructions.
Arithmetic & logical unit (ALU):- Most of all the arithmetic and logical operations
of a computer are executed in the ALU (Arithmetic and Logical Unit) of the processor. It performs
arithmetic operations like addition, subtraction, multiplication, division and also the logical operations
like AND, OR, NOT operations.
Performs arithmetic and logical operations (e.g., addition, subtraction, AND, OR
operations).
Control Unit:- Directs the operation of the processor by interpreting and executing
instructions from the memory.
The control unit is a component of a computer's central processing unit that coordinates
the operation of the processor. It tells the computer's memory, arithmetic/logic unit and input and
output devices how to respond to a program's instructions.
The control unit is also known as the nerve center of a computer system.
Let's us consider an example of addition of two operands by the instruction given as Add LOCA, RO.
This instruction adds the memory location LOCA to the operand in the register RO and places the
sum in the register RO. This instruction internally performs several steps.
Input Unit: Input units are used by the computer to read the data. The most
commonly used input devices are keyboards, mouse, joysticks, trackballs,
microphones, etc.
Output Unit: The primary function of the output unit is to send the processed
results to the user. Output devices display information in a way that the user can
understand.
, Output devices are pieces of equipment that are used to generate information or any
other response processed by the computer. These devices display information that has
been held or generated within a computer.
The most common example of an output device is a monitor.
Storage Unit: The storage unit in computer architecture is responsible for
storing data and instructions that the CPU can access for processing. It can be
broadly classified into two categories based on speed, capacity, and volatility.
Memory:
Primary Memory (RAM): Volatile memory used to store data and
instructions that are currently being used by the CPU.
Cache Memory: Small, very fast memory located close to the CPU to store
frequently used data and instructions for faster access.
Secondary Memory: Non-volatile memory used for long-term data storage
(e.g., hard drives, SSDs).
Bus System: A communication pathway that transfers data between the CPU,
memory, and other peripherals. It includes:
Data Bus: Transfers data.
Address Bus: Specifies memory locations.
Control Bus: Coordinates the activities of the CPU and other
components
General System Architecture:
In Computer Architecture, the General System Architecture is divided into two major classification
units.
Store Program Control Concept
Flynn's Classification of Computers
Store Program Control Concept:-
• The term Stored Program Control Concept refers to the storage of instructions in computer
memory to enable it to perform a variety of tasks in sequence or intermittently.
• The idea was introduced in the late 1040s by John von Neumann who proposed that a
program be electronically stored in the binary-number format in a memory device so that
instructions could be modified by the computer as determined by intermediate computational
results.
, • ENIAC (Electronic Numerical Integrator and Computer) was the first computing system
designed in the early 1940s. It was based on Stored Program Concept in which machine use
memory for processing data.
Stored Program Concept can be further classified in three basic ways:
Von-Neumann Model: Von-Neumann proposed his computer architecture design in 1945
which was later known as Von-Neumann Architecture. It consisted of a Control Unit,
Arithmetic, and Logical Memory Unit (ALU), Registers and Inputs/Outputs.
Von Neumann architecture is based on the stored-program computer concept, where instruction data
and program data are stored in the same memory. This design is still used in most computers
produced today.
A Von Neumann-based computer:
Uses a single processor.
Uses one memory for both instructions and data.
Executes programs following the fetch-decode-execute cycle.
General Purpose System: A general-purpose system typically refers to a computer system
designed to handle a wide range of tasks, with flexible capabilities in terms of processing,
memory management, input/output operations, and more.
