Differences between computer architecture and computer organization

Computer architecture

The portrayal of a computer system from perspective of machine language programming is called computer architecture.
Examples of computer architecture:-
IBM 370 architecture, PDP-11 architecture, Intel 8080 and 8085 architecture, Intel x86 architecture, ARM(Advanced RISC machines) architecture, etc
Images of some computer architectures:-
Computer architecture covers the software aspects of a computer system. Characteristics of a computer system covered by computer architecture:-

1. Word length :- Word length is defined as the number of bits that a internal data register can hold and process at a time.A programmer should have idea about the word length before coding in order to write instructions of bit-length equals to the word length.
2. Instruction set :- A programmer knows what a computer can do from its instruction set. S/he may not have idea about the hardware details. That is why a instruction set is an architectural aspect.
3. Number of registers and their functions :- There are various registers in a processor. They have their own functions. Some registers are used to store data, while some stores addresses. Register called accumulator is used to store results by default. These aspects should be exposed to the programmer. That is why number of registers and their functions is an architectural aspect.
4. Addressing modes :- Instructions fetch and stores data from registers and memory addresses defined by various addressing modes. Addressing modes direct impacts the logical execution of the program that is why, addresing modes are an architectural aspect.
5. Bus structure,
6. I/O mechanism,
7. Memory addressing techniques,

Computer organization

The portrayal of hardwares and their interconnections in order to realize the computer system architecture is called computer organization.
For a given computer architecture there can be various computer organizations.
Computer organization covers the electronic aspects of a computer system. Characteristics of a computer system covered by computer organization:-

1. Details about internal structure of memories,
2. Interfacing circuitary for bus, memory and peripherals,
3. Circuitary details for timing and control signals,

Computer organization vs computer architecture

Computer architecture	Computer organization
Definition
The portrayal of a computer system from perspective of machine language programming is called computer architecture.	The portrayal of hardwares and their interconnections in order to realize the computer system architecture is called computer organization
Objectives
Computer architecture depicts the entire computer system as a programming model so that machine-language programmer can develop softwares.	The objective of computer organization is to realize computer architecture.
Relation A computer architecture can be realized by numerous forms of computer organizations.
Choosing an instruction is an architectural concern.	How the instruction will be executed is an organizational concern.
Number of registers, types of registers and word length is an architectural concern.	The electronic aspect that how a register will be selected for a particular instruction is an organizational concern.
Aspects included
Computer architecture covers the software aspects of a computer system. Characteristucs of a computer system covered by computer architecture:- Word length, Instruction set, Number of registers, Registers bit length and functions Addressing modes, Bus structure, I/O mechanism, Memory addressing techniques etc	Computer organization covers the electonic aspects of the compter system. Characteristucs of a computer system covered by computer organization are as follows:- Details about internal structure of memories, Interfacing circuitary for bus, memory and peripherals, Circuitary details for timing and control signals,
Hardware exposure
Hardware exposure at architectural level is superficial since only those hardware details are included which are important from view point of machine language programming.	Detailed circuitary of internal structure and interfacing provided.
Applications
For developing softwares.	For realising the computer architecture.
A computer architecture lasts longer than a computer organizational.	A computer organization is replaced by another organization belonging to same architecture with change in technology.

Computer design

Computer design is defined as the process of designing circuitary for the hardware components of the computer system.