1. Computer Architecture
Lecture 1
Lecturer: Hina Shafique

2. Text Book
Computer Organization and Architecture By William Stallings, 9th Edition

3. Grading Criteria Assignments Quizzes Presentations Research Paper
Semester Project
Mid Term
Final Term

4. Assignments – Delivery
to me
subject: Comp-Architecture Assignment X (X -> 1,2,3)
Naming of attachments (zip them)
FirstLastName_ Section_Assignment X.zip

6. Introduction to Computer System
Representation of Basic Information
The basic functional units of computer are made of electronic circuits and it works with electrical signal.
We provide input to the computer in the form of electrical signal and get the output in the form of electrical signal.
There are two basic types of electrical signals, namely, analog and digital.
The analog signals are continuous in nature and digital signals are discrete in nature.

7. The electronic device that works with continuous signals is known as analog device and the electronic device that works with discrete signals is known as digital device.
Computer is a digital device, which works on two levels of signal. We say these two levels of signal as High and Low.
The High-level signal basically corresponds to some high-level signal (say 5 Volt or 12 Volt) and Low-level signal basically corresponds to Low-level signal (say 0 Volt).
Since Computer is a digital electronic device, we have to deal with two levels of electrical signals

8. Computer is used to solve mainly numerical problems.
it is not convenient to work with symbolic representation.
So, we use 0 to represent LOW and 1 to represent HIGH.
0     means    LOW 1     means    HIGH
With the symbol 0 and 1, we have a mathematical system, which is known as binary number system.
The smallest unit of information that is represented in computer is known as Bit ( Binary Digit ), which is either 0 or 1.
Four bits together is known as Nibble, and Eight bits together is known as Byte.

9. Computer technology has made incredible improvement in the past half century. In the early part of computer evolution, there were no stored-program computer, the computational power was less and on the top of it the size of the computer was a very huge one.
Today, a personal computer has more computational power, more main memory, more disk storage, smaller in size and it is available in affordable cost.

10. What is a computer?
A computer is an electronic machine that processes information— in other words, an information processor: It takes in raw information (or data) at one end, stores it until it's ready to work on it, chews and crunches it for a bit, then spits out the results at the other end. All these processes have a name. Taking in information is called input, storing information is better known as memory (or storage), chewing information is also known as processing, and spitting out results is called output.

11. Back in the 1970s and 1980s, if you wanted a home computer to do almost anything at all, you had to write your own little program to do it. For example: Before you could write a letter on a computer, you had to write a program that would read the letters you typed on the keyboard, store them in the memory, and display them on the screen. Writing the program usually took more time than doing whatever it was that you had originally wanted to do (writing the letter). Pretty soon, people started selling programs like word processors to save you the need to write programs yourself.

12. How Computer Operates?
A computer operates under the control of instructions stored in its own memory unit, that can accept data (input), process data arithmetically and logically, produce output from the processing and store the results for future use.

13. Block Diagram of Computer

15. What is Architecture?
Architecture is both the process and the product of planning, designing, and constructing buildings and other physical structures. 

16. Architecture The art or science of building.
A style and method of design and construction.

17. What is Computer Architecture?
Computer architecture, like other architecture, is the art of determining the needs of the user and then designing to meet those needs as effectively as possible within economic and technological constraints.
Computer Architecture is the science and art of selecting and interconnecting hardware components to create computers that meet functional, performance and cost goals.

21. Architecture vs Organization
Architecture is those attributes that are visible to the programmer
Instruction set, number of bits used for data representation, I/O mechanisms, addressing techniques.
What instructions should be there.
e.g. Is there a multiply instruction?

22. Organization refers to the operational units and their interconnections.
Control signals,
interfaces between the computer and peripherals,
memory technology.
How instruction is executed.
e.g. Is there a hardware multiply unit or is it done by repeated addition?

23. Architecture
The term Computer Architecture was coined/invented at IBM in 1960s.
It was used to refer to the programmer visible portion of the instruction set of the IBM 360 family of computers.
The structure of a computer that a machine language programmer must understand to write correct programs for the machine.

24. Who is Computer Architect?
A person who designs computers.

25. What do we mean by “design”?
Design is the process of devising/developing a system, component, or process to meet desired needs.
It is a decision-making process (usually iterative), in which the basic sciences, and math and engineering sciences are applied to convert resources optimally to meet a stated objective.

26. Basic Computer Model and different units of Computer
The model of a computer can be described by four basic units in high level abstraction
These basic units are:
Central  Processor  Unit               
Input  Unit                  
Output  Unit                      
Memory  Unit 

27. Central Processor Unit (CPU) :
Central processor unit consists of two basic blocks :
The program control unit has a set of registers and control circuit to generate control signals.
The execution unit or data processing unit contains a set of registers for storing data and an Arithmetic and Logic Unit (ALU) for execution of arithmetic and logical operations.
In addition, CPU may have some additional registers for temporary storage of data.

28. Input Unit :
With the help of input unit data from outside can be supplied to the computer.
Program or data is read into main storage from input device or secondary storage under the control of CPU input instruction.
Example of input devices: Keyboard, Mouse, Hard disk, Floppy disk, CD-ROM drive etc.

29. Output  Unit :
With the help of output unit computer results can be provided to the user or it can be stored in storage device permanently for future use.
Output data from main storage go to output device under the control of CPU output instructions.
Example of output devices: Printer, Monitor, Plotter, Hard Disk, Floppy Disk etc.

30. Memory Unit :
Memory unit is used to store the data and program.
CPU can work with the information stored in memory unit. (when the time is right, the control unit sends items from memory to the arithmetic/logic unit, where an arithmetic operation or logical operation is performed).
The memory unit is termed as primary memory or main memory module. These are basically semi conductor memories.

31. There ate two types of semiconductor memories -
Volatile Memory          : RAM (Random Access Memory).
Non-Volatile Memory : ROM (Read only Memory),  PROM (Programmable ROM) EPROM (Erasable PROM),  EEPROM (Electrically Erasable PROM).

32. Secondary Storage:

33. Structure & Function
Structure is the way in which the components are interrelated.
Function is the operation of individual components as part of the structure

34. Function All computer functions are: Data processing Data storage
Data movement
Control
Functional view of the computer ->

35. Operations (1) Data movement

36. Operations (2) Storage

37. Operation (3) Processing from/to storage

38. Operation (4) Processing from storage to I/O

39. Structure The Computer CPU Main memory I/O System interconnection
Controls the operation of the computer and performs its data processing functions.
Main memory
Stores data
I/O
Moves data between the computer and its external environment
System interconnection
Provides for communication among CPU, main memory, and I/O

40. Structure - Top Level Computer Peripherals Central Main Processing
Unit
Main
Memory
Computer
Systems
Interconnection
Input
Output
Communication
lines

41. Structure - The CPU CPU Arithmetic Computer and Registers Logic Unit
I/O
System
Bus
CPU
Internal CPU
Interconnection
Memory
Control
Unit

42. Structure - The Control Unit
CPU
Sequencing
Logic
ALU
Control
Unit
Internal
Bus
Control Unit
Registers and
Decoders
Registers
Control
Memory

43. Control Unit: Controls the operation of the CPU and hence the computer.
Arithmetic and logic unit (ALU): Performs the computer’s data processing function.
Registers: Provides storage internal to CPU
CPU interconnection: some mechanism that provides for communication among the control unit, ALU and registers.

44. Assignment 1: What's the difference between Core i3, i5 and i7 processors?
Due Date: First class After Eid break