1. Computer organization and Architecture
Dr Ajay Sharma
Department of CSE
SRM University, Haryana

2. Architecture & Organization
Architecture is those attributes visible to the programmer
Instruction set, number of bits used for data representation, I/O mechanisms, addressing techniques.
e.g. Is there a multiply instruction?
Organization is how features are implemented
Control signals, interfaces, memory technology.
e.g. Is there a hardware multiply unit or is it done by repeated addition?

3. Computer organization
Encompasses all physical aspects of computer systems.
E.g., circuit design, control signals, memory types.
How does a computer work?
Computer architecture
Logical aspects of system implementation as seen by the programmer.
E.g., instruction sets, instruction formats, data types, addressing modes.
How do I design a computer?

4. The components from which computers are built, i. e
The components from which computers are built, i.e., computer organization.
•In contrast, computer architecture is the science of integrating those components to achieve a level of functionality and performance.
•It is as if computer organization examines the lumber, bricks, nails, and other building material
•While computer architecture looks at the design of the house.

5. What is "Computer Architecture” A system concept integrating software, hardware, and firmware to specify the design of computing systems
Application
Operating
Compiler
System
Instruction Set
Architecture
Instr. Set Proc.
I/O system
Digital Design
Circuit Design
° Under a set of rapidly changing Forces

6. Why study computer organization and architecture?
Design better programs, including system software such as compilers, operating systems, and device drivers.
Optimize program behavior.
Evaluate (benchmark) computer system performance.
Understand time, space, and price tradeoffs.

7. Structure & Function
Structure is the way in which components relate to each other
Function is the operation of individual components as part of the structure

8. UNIT-I INTRODUCTION Evolution of Computer Systems Computer Types
Functional units
Basic operational concepts
Bus structures
Memory location and addresses
Memory operations
Addressing modes
Design of a computer system
Instruction and instruction sequencing,
RISC versus CISC.

9. Brief History of Computer Evolution
Two phases:
before VLSI 1945 – 1978
ENIAC
IAS
IBM
PDP-8
VLSI  present day
microprocessors !
VLSI = Very Large Scale Integration

10. Evolution of Computers FIRST GENERATION (1945 – 1955)
Program and data reside in the same memory (stored program concepts – John von Neumann)
ALP was made used to write programs
Vacuum tubes were used to implement the functions (ALU & CU design)
Magnetic core and magnetic tape storage devices are used
Using electronic vacuum tubes, as the switching components

11. Electronic Numerical Integrator And Computer (ENIAC) built in 1946.
Size: 30’ x 50’ room, 18,000 vacuum tubes
1500 relays, weighed 30 tons
designers
1. John Mauchly
2. J. Presper Eckert
Features of First Generation
Use of vacuum tubes
Big & Clumsy
High Electricity Consumption
Programming in Mechanical Language
Larger AC were needed
Lot of electricity failure occurred

12. SECOND GENERATION (1955 – 1965)
Transistor were used to design ALU & CU
HLL is used (FORTRAN)
To convert HLL to MLL compiler were used
Separate I/O processor were developed to operate in parallel with CPU, thus improving the performance
Invention of the transistor which was faster, smaller and required considerably less power to operate

13. Smaller & Cheaper.
Less heat dissipation.
Solid State device.
Transistors Made from Silicon (Sand).
Invented 1947 at Bell Labs.
William Shockley et al.

14. THIRD GENERATION (1965-1975) IC technology improved
Improved IC technology helped in designing low cost, high speed processor and memory modules
Multiprogramming, pipelining concepts were incorporated
DOS allowed efficient and coordinate operation of computer system with multiple users
Cache and virtual memory concepts were developed
More than one circuit on a single silicon chip became available

15. FOURTH GENERATION (1975-1985) CPU – Termed as microprocessor
INTEL, MOTOROLA, TEXAS,NATIONAL semiconductors started developing microprocessor
Workstations, microprocessor (PC) & Notebook computers were developed
Interconnection of different computer for better communication LAN,MAN,WAN
Computational speed increased by 1000 times
Specialized processors like Digital Signal Processor were also developed

16. BEYOND THE FOURTH GENERATION (1985 – TILL DATE)
E-Commerce, E- banking, home office
ARM, AMD, INTEL, MOTOROLA
High speed processor - GHz speed
Because of submicron IC technology lot of added features in small size

17. Classes of Computers Desktop Game console
Computers can be classified, or typed, many ways. Some common classifications are summarized below.
Classes by size
a. Microcomputers (personal computers)
Desktop
Game console
b. Minicomputers (midrange computers)
c. Mainframe computers
d. Supercomputers
Classes by function
a.Servers :
b. Workstations :
c. Information appliances (E.g. Play music)
d. Embedded computers:

18. Classes by Technology
Analog
Digital
Hybrid

19. Comparisons between different types of computers:
Components
Physical Size and Capacity
Cost
Usage
Microcomputer
All components in a single unit
Smallest
Cheapest
At homes, in schools and offices
Minicomputer
Several functional units
Small
Cheap
In universities, medium-sized companies, departments of large companies
Mainframe computer
Several separate units
Large
Expensive
In large organizations, universities, government
Supercomputer
Largest
Most expensive
In scientific research, weather forecasting, space exploration, military defense

20. COMPUTER TYPES Computers are classified based on the parameters like
Speed of operation
Cost
Computational power
Type of application

21. DESK TOP COMPUTER NOTEBOOK COMPUTER
Processing &storage units, visual display &audio uits, keyboards
Storage media-Hard disks, CD-ROMs
Eg: Personal computers which is used in homes and offices
Advantage: Cost effective, easy to operate, suitable for general purpose educational or business application
NOTEBOOK COMPUTER
Compact form of personal computer (laptop)
Advantage is portability

22. ENTERPRISE SYSTEM (MAINFRAME)
WORK STATIONS
More computational power than PC
Costlier
Used to solve complex problems which arises in engineering application (graphics, CAD/CAM etc)
ENTERPRISE SYSTEM (MAINFRAME)
More computational power
Larger storage capacity
Used for business data processing in large organization
Commonly referred as servers or super computers

23. SERVER SYSTEM SUPER COMPUTERS
Supports large volumes of data which frequently need to be accessed or to be modified
Supports request response operation
SUPER COMPUTERS
Faster than mainframes
Helps in calculating large scale numerical and algorithm calculation in short span of time
Used for aircraft design and testing, military application and weather forecasting

24. HANDHELD Also called a PDA (Personal Digital Assistant).
A computer that fits into a pocket, runs on batteries, and is used while holding the unit in your hand.
Typically used as an appointment book, address book, calculator, and notepad.
Can be synchronized with a personal microcomputer as a backup.

25. Basic Terminology Computer Hardware Software Network
A device that accepts input, processes data, stores data, and produces output, all according to a series of stored instructions.
Hardware
Includes the electronic and mechanical devices that process the data; refers to the computer as well as peripheral devices.
Software
A computer program that tells the computer how to perform particular tasks.
Network
Two or more computers and other devices that are connected, for the purpose of sharing data and programs.
Peripheral devices
Used to expand the computer’s input, output and storage capabilities.

26. Basic Terminology Input Data Information Output Processing Memory
Whatever is put into a computer system.
Data
Refers to the symbols that represent facts, objects, or ideas.
Information
The results of the computer storing data as bits and bytes; the words, numbers, sounds, and graphics.
Output
Consists of the processing results produced by a computer.
Processing
Manipulation of the data in many ways.
Memory
Area of the computer that temporarily holds data waiting to be processed, stored, or output.
Storage
Area of the computer that holds data on a permanent basis when it is not immediately needed for processing.

27. Basic Terminology
Assembly language program (ALP) – Programs are written using mnemonics
Mnemonic – Instruction will be in the form of English like form
Assembler – is a software which converts ALP to MLL (Machine Level Language)
HLL (High Level Language) – Programs are written using English like statements
Compiler - Convert HLL to MLL, does this job by reading source program at once

28. Basic Terminology
Interpreter – Converts HLL to MLL, does this job statement by statement
System software – Program routines which aid the user in the execution of programs eg: Assemblers, Compilers
Operating system – Collection of routines responsible for controlling and coordinating all the activities in a computer system

29. Computing Systems Computers have two kinds of components:
Hardware, consisting of its physical devices (CPU, memory, bus, storage devices, ...)
Software, consisting of the programs it has (Operating system, applications, utilities, ...)

30. FUNCTIONAL UNITS OF COMPUTER
Input Unit
Output Unit
Central processing Unit (ALU and Control Units)
Memory
Bus Structure

31. The Big Picture Since 1946 all computers have had 5 components!!!
Processor
Input
Control
Memory
ALU
Output
Since 1946 all computers have had 5 components!!!

32. Coordinates How Information is Used
IMPORTANT SLIDE !
Function
ALL computer functions are:
Data PROCESSING
Data STORAGE
Data MOVEMENT
CONTROL
NOTHING ELSE!
Data = Information
Coordinates How Information is Used

33. INPUT UNIT: OUTPUT UNIT:
Converts the external world data to a binary format, which can be understood by CPU
Eg: Keyboard, Mouse, Joystick etc
OUTPUT UNIT:
Converts the binary format data to a format that a common man can understand
Eg: Monitor, Printer, LCD, LED etc

34. CPU The “brain” of the machine
Responsible for carrying out computational task
Contains ALU, CU, Registers
ALU Performs Arithmetic and logical operations
CU Provides control signals in accordance with some timings which in turn controls the execution process
Register Stores data and result and speeds up the operation

35. Computer Architecture
Input/Output and Storage
Disks, WORM, Tape
RAID
Emerging Technologies
Interleaving
Bus protocols
DRAM
Coherence,
Bandwidth,
Latency
Memory
Hierarchy
L2 Cache
L1 Cache
Addressing,
Protection,
Exception Handling
VLSI
Instruction Set Architecture
Pipelining, Hazard Resolution,
Superscalar, Reordering,
Prediction, Speculation
Pipelining and Instruction
Level Parallelism 35