1. Overview of Computer Architecture and Organization
Module I
Overview of Computer Architecture and Organization

2. Introduction of Computer Architecture and Organization

3. University Question
Differentiate between Computer Architecture and Organization (05 Marks)

4. Computer Architecture
Defn: It refers to the attributes of a system visible to a programmer that have a direct impact on the logical execution of a program
E.g. : Instruction set, No. of bits for various datatypes,…

5. Computer Organization
Defn: It refers to the operational units and their interconnections that realize the architectural specifications.
E.g. Interfaces, Memory Used,…

6. Example Whether to have multiply instruction?
Architectural Issue
Organizational Issue
Whether to have multiply instruction?
Whether to include a multiply unit or go for repeated addition?

7. Example : IBM System/370 This architecture was introduced in 1970
Still it is used in IBM’s Mainframe product line

10. Introduction
Information handled by computer are of two types: Instructions & Data
Instructions: They are explicit commands that
Govern transfer of information within and out of computer
Specifies arithmetic and logical operations to be performed

11. Introduction Program: Data:
A list of instructions that performs a task
Stored in memory
Processor fetches instructions and perform operations
Computer is controlled by stored programs
Data:
They are encoded numbers and characters used as operands by instruction e.g. BCD and ASCII

12. Functional Units of Computer

13. Functional Units of Computer
A computer consists of 5 parts:
Input Unit
Output Unit
Memory
Arithmetic and Logic Unit (ALU)
Control Unit

14. Input Unit Accepts coded information from E.g. for Input Device :
human operators with help of electromechanical devices
other computers with digital communication lines (using NIC)
E.g. for Input Device :
Most well known : Keyboard
Graphic Input Devices : joysticks, mouse
Microphones : for audio input
The information received:
Either stored in memory or
Immediately used by ALU

15. Input Devices Mouse – pointing device Keyboard
Microphone – speech-recognition
Digital Cameras

16. Output Unit Counterpart of input unit
It sends processed results to outside world
E.g. printer, monitor

17. Output Devices
Monitor
Printer
Speakers

18. Memory Unit Stores program and data Two types : Primary and Secondary
Fast memory
Contains semiconductor storage cells storing 1-bit
Group of cells called word can be stored and retrieved in one basic operation
Each word is associated with an address
No. of bits in word = wordlength

19. Memory Unit Primary: Secondary: RAM :
Any location can be reached in short fixed amount of time (called Memory Access Time)
Secondary:
Stores large amount of infrequently accessed data
E.g. magnetic disks, optical disks (CD ROM), etc..

20. Storage Devices Random Access Memory– RAM CD/DVD Drive Hard Drive
Floppy Disk Drive
CD/DVD Drive
Random Access Memory– RAM
Pen Drive

21. Arithmetic and Logic Unit (ALU)
Performs arithmetic and logical operations
It is done by
bringing operands into processor
Perform required operation
Store result in memory or processor for immediate use
Operands are stored in high speed elements called registers

22. Control Unit
Control unit (CU) of a processor translates from machine instructions to the control signals for the microoperations that implement them

23. MCQs
1. Which memory device is generally made of semi-conductors ? a) RAM b) Hard-disk c) Floppy disk d) CD disk

24. MCQs
2. The ALU makes use of _______ to store the operands. a) Adders b) Registers c) Heap d) Stack

25. MCQs
3. A list of instructions used by a computer is called a. program b. CPU c. text d. output

26. MCQs 4. Which of the following is the most powerful
type of the computer
main frame
super conductor
c. micro computer
d. super computer

27. MCQs
5. Memories in which any location can be reached in a fixed and short amount of time after specifying its address is called a. sequential access memory b. random access memory c. secondary memory d. mass storage

28. Structure and Functions
A computer is a Complex System
Computer is a hierarchical set of interrelated subsystems.
This nature is for design and description.

29. Structure and Functions
Structure: The way in which the components are interrelated
Function: The operation of each individual component

30. Basic Functions of a Computer
Data Processing
Data Storage
Data Movement
Control

32. Data Processing Data take variety of forms
Range of processing requirements is broad.

33. Data Storage
Short Term : store data that are being worked on at any given moment
Long Term : store files of data for subsequent retrieval and update

34. Data Movement
Computer uses devices to serve as source or destination of data called peripherals (I/O devices)
For longer distances, it is known as data communication.

35. Control
Control unit manages resources and orchestrates the functional parts
There are 4 possible types of operation.

36. Data from one peripheral to another (Data movement)

37. Data from peripheral to storage (Data Storage)

38. Processing data in storage

39. Data transfer between storage and external environment

40. Structure of Computer There are 4 major structural components:
Central Processing Unit ( CPU)
Main Memory
I/O
System Interconnections

41. Structure of Computer Peripherals Central Main Processing Memory Unit
Input
Output
Systems
Interconnection
Peripherals
Communication
lines
Central
Processing
Unit

42. Central Processing Unit (CPU)
Most complex component
Its major component are
Control Unit : controls the operation of CPU
Arithmetic and Logic Unit : performs data processing
Registers: provide storage internal to CPU
CPU Interconnection: provide communication among components

43. Arithmetic Computer and Registers Login Unit Internal CPU
Control
Unit
Internal CPU
Interconnection
Registers
CPU
I/O
Memory
System
Bus

44. Control Unit Most common implementation: microprogrammed
It operates by executing microinstructions.

45. Control Unit CPU Sequencing Login Control Unit Registers and Decoders
Memory
Control Unit
Registers and
Decoders
Sequencing
Login
Unit
ALU
Registers
Internal
Bus

46. Types of Computer Languages
High
Level
Low Level
Independent of
Machine
Corresponds directly to a specific machine

47. A binary language interpreted directly into hardware
Low Level Language
Machine
Assembly
A binary language interpreted directly into hardware
A slightly more user friendly language that directly corresponds to machine language

48. Machine Language most elementary level of programming language
First type of programming language
It is usually written in hex.
It is represented by a string of binary digits 0 and 1.
The symbol
0 => absence of an electric pulse
1 => presence of an electric pulse.

49. Machine Language : Advantages
It makes fast and efficient use of computer.
It requires no translator since it is directly understood by the computer.

50. Machine Language : Disadvantages
All operation codes have to be remembered
All memory addresses have to be remembered.
It is hard to amend or find errors

51. Assembly Language
It was developed to overcome inconveniences of machine language.
In this, operation codes and operands are given in the form of alphanumeric symbols
It can combine in a maximum of five-letter combinations e.g. ADD for addition, SUB for subtraction, START, LABEL etc.

52. Assembly Language also called Symbolic Programming Language
It is also very difficult and needs a lot of practice to master it.
They are used to help in compiler orientations.
The instructions are converted to machine codes by translator and then executed.

53. Assembly Language : Advantages
It is easier to understand and use compared to machine language
It is easy to locate and correct errors
It can be easily modified.

54. Assembly Language : Disadvantages
It is machine dependent hence the programmer has to understand the hardware

55. High Level Languages It uses formats that are similar to English
It enable people to write programs in their own native language (English)

56. High Level Language: Advantages
User-friendly
Uses English Vocabulary and well-known symbols
Easy to learn
Easier to maintain
Problem oriented
Translation to lower language is easy
Independent of machine

57. High Level Language: Disadvantages
High level to machine level languages takes time
Code generated may not be efficient.