1. CST 303 COMPUTER SYSTEMS ARCHITECTURE (2 CREDITS)‏
DEPARTMENT OF COMPUTER SCIENCE & TECHNOLOGY
FACULTY OF SCIENCE & TECHNOLOGY
UNIVERSITY OF UWA WELLASSA 1 1

2. COURSE CONTENT Computer Abstractions & Technology
Performance Measurement & Comparison
Data Representations
Assembly Language
Computer Arithmetic
Data path and Control of a Processor
Pipelining
Memory Systems Architecture and Hierarchical Memory Systems
Peripheral Devices and IO
Parallel Processing 2 2 2

3. COURSE SUMMERY Methodology: Two hours of lectures per week
Methods of Evaluations:
Continuous Assessments :60%
End Semester Examination :40%
Recommended Texts :
Computer Organization and Design,Davied A.Patterson,John L.Hennessy,3rd edition 3 3 3

4. Chapter 1 Computer Abstraction & Technology‏
DEPARTMENT OF COMPUTER SCIENCE & TECHNOLOGY
FACULTY OF SCIENCE & TECHNOLOGY
UNIVERSITY OF UWA WELLASSA 4 4

5. What is Architecture?
The role of a building architect: 5 5 5

6. What is Computer Architecture?
The role of a computer architect: 6 6 6

7. What is Computer Architecture?
Computer architecture is the theory behind the design of a computer. It sets the standard for all devices that connect to it and all the software that runs on it. 7 7 7

8. Design Goals of Computer Architecture
Low cost
Per unit manufacturing cost (wafer cost)
Cost of making first chip after design (mask cost)
Design cost (huge design teams)
Low power 8 8 8

9. Constant Change in Computer Architecture9 9 9

10. Rapid Change in Computer Architecture
Exciting: perhaps the fastest moving field … ever
Processors vs. cars
1985: processors = 1 MIPS, cars = 60 MPH
2000: processors = 500 MIPS, cars = 30,000 MPH? 10 10 10

11. Challenge of Computer Architecture
“ Balancing the relative importance of these goals and constantly changing is the major challenge in Computer Architecture” 11 11 11

12. “Computer Architecture is NOT Computer Hardware12 12 12

13. Definition of Computer Architecture
Baer :
“ The design of the integrated system which provides a useful tool to the programmer”
Hayes :
“ The study of the structure,behaviour and design of computers”
Hennessy & Patterson :
“ The interface between the h/w and the lowest level s/w 13 13 13

14. Definition of Computer Architecture
In general,
“Computer architecture refers to attributes of the system visible to programmer which have direct impact on the execution of a program” 14 14 14

15. Why we study Computer Architecture?
General user :
Understand system capabilities and limitations
Make informed decisions
Improve communication with information technology professionals.
Programmer :
Create efficient application s/w for specific processing needs. 15 15 15

16. Why we study Computer Architecture?
System Architecture :
Install,configure,maintain and upgrade
Make informed decisions
Improve communication with information technology professionals. 16 16 16

17. History of Computer Architecture
Milestones :
The zeroth generation - Mechanical computers ( ) 17 17 17

18. History of Computer Architecture
Milestones :
2. The first generation - Vacuum tubes ( ) 18 18 18

19. History of Computer Architecture
Milestones :
3. The second generation - Transistors ( ) 19 19 19

20. History of Computer Architecture
Milestones :
4. The third generation - Integrated Circuits ( ) 20 20 20

21. History of Computer Architecture
Milestones :
5. The fourth generation - Micro processor/Very large-scale integration (VLSI) (1980-????) 21 21 21

22. Beginning of Modern Computer Architecture
Structure of a basic computer system has being composed of the following components:
Central Arithmetic Unit / Arithmetic Logic Unit (ALU).
Unit which performs the computer's computational and logical functions;
Memory
Computer's main or fast memory. E.g. – Random Access Memory (RAM);
Control Unit
Unit which directs other components of the computer to perform certain actions.
E.g. – Directing the fetching of data or instructions from memory to be processed by the ALU; and
Input and output
Devices which use for input and output data. E.g. – Keyboard for input and display monitor for output. 22 22 22

23. Beginning of Modern Computer Architecture …
Harvard Architecture
Control Unit
ALU
I/O
Data
Memory
Instruction 23 23 23

24. Beginning of Modern Computer Architecture …
Von Neumann Architecture
Stored Program Principal
Computer is act upon internally stored
instructions
ALU
Control Unit
Data
Memory
I/O 24 24 24

25. Modern Computer Architecture
Modern Computer incorporate aspects of both architecture
E.g.
On chip Cache memory divided into instruction cache and data cache but RAM is not divided like that. 25 25 25

26. Modern Computer Architecture …
Modern Computer Architecture is an interconnected system of processor, main memory, secondary storage devices, I/O devices & system bus which is driven by an external clock. 26 26 26

27. Modern Computer Architecture …
Processor
The brain of the computer
Each CPU has specific list of instructions that can be execute ;Instruction Set
The basic function of CPU is to fetch instructions from memory decode them and execute 27 27 27

28. Modern Computer Architecture …
Main Parts CPU
Control Unit
Controls processing of instructions and movement of data within CPU
ALU
Perform all calculations and logical functions using logic gates
Registers
A group of storage locations in the processor for holding instructions being executed and addresses to be accessed 28 28 28

29. Modern Computer Architecture …
Main Memory/ Primary Storage/ Internal Memory
Storage which is directly accessible by the
CPU
E.g. Registers ,cache,RAM,ROM
Features
High Speed
Less amount of storage
Expensive
Placed near CPU 29 29 29

30. Modern Computer Architecture …
Secondary Storage/ External Memory
Storage which is not directly accessible by the CPU
E.g. Hard disk, floppy disks, optical storage(CD,DVD),
USB Flash drivers
Features
Less speed compare to primary storage
Large amount of storage
Inexpensive
Distance from CPU is large 30 30 30

31. Modern Computer Architecture …
Input/ Output Devices
I/O devices provide an efficient mode of communication between the computer and the outside environment
E.g. Input Devices:keyboard,mouse,scanner
Output Devices:monitor,printers 31 31 31

32. Modern Computer Architecture …
System Bus
A collection of wires which connects the processor to main memory, storage devices and I/O devices
Each of the wires in the bus can be switched on/off
Three types of buses
Address bus
Data bus
Control bus
228 pin interface chip 32 32 32

33. Modern Computer Architecture …
Address Bus
Carries the addresses in memory or port in I/O units can
Number of wires affects how many storage locations can be accessed
i.e. if wires are n address locations 2n
Data Bus
Carries data to and from the processor
Control Bus
Made up of a number of separate wires each with their own function
E.g. Read/Write line Reading from or writing to main memory 33 33 33

34. Modern Computer Architecture …
Clock
The clock is a circuit that emits continuous stream of precise high and low pulses that are all exactly the same length.
Clock regulates the rate at which instructions are executed and synchronizes all the various computer components.
Transferring four data in single clock pulse 34 34 34

35. Multi-Level Computing System
In modern Computer Architecture the whole computer system can be viewed as a “multi-layered machine” consisting of several layers of software top of several layers of hardware, each one performing some well-defined function. 35 35 35

36. Multi-Level Computing System …36 36 36

37. Multi-Level Computing System …
Application Layer
The application layer is the language of the computer as seen by the end-user.
Higher Order Software Layer
The higher order software layer covers all programs in languages other than machine language, which require translation into machine code before they can be executed. 37 37 37

38. Multi-Level Computing System …
Operating System Layer
The operating system layer controls the way in which all software uses the underlying hardware.
It also hides the complexities of the hardware from other software by providing its own facilities, which enable software to use the hardware more simply.
Machine Layer
The machine layer is the lowest level at which a program can be written and indeed it is only machine language instructions, which can be directly interpreted by the hardware. 38 38 38

39. Multi-Level Computing System …
Micro programmed Layer
The micro programmed layer interprets the machine language instructions from the machine layer and directly causes the digital logic elements to perform the required operations.
It is, in effect, a very basic inner processor and is driven by its own primitive control program instructions held in its own primitive inner ROM.
These program instructions are called “microcode” and control program is called a “microprogram”. 39 39 39

40. Multi-Level Computing System …
Digital Logic Layer
All the most basic operations of the machine are provided at digital logic layer level.
The basic elements at this level can store, manipulate and transmit data in the form of simple binary representations.
The digital logic elements are called “gates”.
These standard digital logic devices are combined together to form computer processors, computer memories and major components of units used for input and output. 40 40 40

41. Multi-Level Computing System …
Physical Layer
The physical layer is an electrical and electronic component layer.
(Very important, but it is largely outside the subject of computer science)
The most sophisticated modern computer devices are built from simple electronic components such as transistors, diodes, capacitors and resistors (not normally as discrete components) and these components rely on suitable power supplies and operating environments. 41 41 41

42. Fetch – Decode – Execution Cycle
Start
Fetch the next instruction from memory
Decode the instruction
More Instruction
Store any result back in memory No
Stop
Yes 42 42 42