the Von-Neuman Model

1. COMPUTER ARCHITECTURE
CSC 3314
LECTURE 2
Department of Maths and Computer-
Science
Faculty of Natural and Applied Science
BY
UMAR DANJUMA MAIWADA

2. BASIC CONCEPTS
 Data: Numbers/ ASCII letter codes that correspond to
the variables/constant in our program.
 Instruction: interpreted by the computer and control
what happens to data.
 Both are stored in read-write memory but in different location
 Both look the same but are processed differently
 Both are binary in representation and can be manipulated
using digital logic
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3. THE INITIAL CONCEPT OF THE MACHINE
 Manipulate data
 Interprets instructions (decide what todo)
 Store words (data and instructions)
 Keep track of things (what happens next)
 Get instructions and data (in and out)
 A computer system needs
 Cpu
 Storage
 i/o
 connectors 3

4. STRUCTURE AND FUNCTIONS OF A COMPUTER
 Structure: is a way in which components are
interrelated
 Function: is the operation of each individual
components as part of a structure.
 Function of a computer
 Data processing : take variety of form
 Data storage: file storage for retrieval and update
 Data movement : sources and destination of data
 Control: control unit helps in controlling the above units
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5. REGISTERS
 They are used for active instructions and
data which are currently being used.
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6. SOME REGISTERS
 Memory buffer register: contains a word to be stored in
memory or is used to receive a word form memory
 Memory address register: specifies the address in
memory of the word to be written from or read into the
MBR
 Instruction register: contains the 8 bit up code
instructions being executed
 Instruction buffer register: employed to temporarily hold
the right hand instruction from a word in memory
 Program counter: contains the address of the next
instruction to be fetched from the memory
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7. EXECUTION UNIT AND BUS UNIT
 The EU contains
 ALU
 CU
 Register
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8. SYSTEM UNIT
 Is an important hardware element of the PC
 A system board
 Power supply
 Expansion slot for optional board
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9. FEATURES OF THE SYSTEM BOARD
 Microprocessor: performs all execution of an
instructions
 RAM
 ROM
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10. CPU
 Is the most important development in integrated
circuit technology were software's are executed.
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11. FUNCTIONS OF THE CPU
 Mathematical operation
 Logical manipulation
 Data manipulation
 Control operation
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12. BUS
 Data bus: carries information to and from CPU. The
size represent a bit
 Address bus: it tells the location of data in the
memory or I/O before CPU can read or write data.
 Control bus: contains control signal for coordinating
the operation of the CPU with other devices
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13. TYPICAL MOTHERBOARD
 Motherboard with slots for holding parts
 CPU has a fan
 RAM data storage
 I/O input and output
 Bus
 Power supply
 Storage
 Video display controller
 Networking
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14. THE VON-NEUMANN MODEL
 Input unit
 Output unit
 ALU
 Memory unit
 Control unit
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15. 15
Memory unit
Control unit
Input unit Output unitALU

16. 16
CPU Main
Memory
Long term
memory
I/O and
other
peripherals
Bus
The basic Von-Neumann Design

17. EXECUTION CYCLE
 Processor cycle
 There is a timer by an external clock signal
 It is supplied to the processor
 Operations are broken up into circles
 The fastest operation will take one clock cycle and other will
now take several cycle to complete the processor operation
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18. THE NEXT INSTRUCTION
LOAD THE NEXT INSTRUCTION FROM
MEMORY INTO THE IR
UPDATE THE PC TO POINT AT THE NEXT
INSTRUCTION
DETERMINE THE TYPE OF INSTRUCTION
FETCHED
DETERMINE THE ADDRESS OF THE DATA IF
NEEDED
FETCH THE DATA FROM MEMORY
EXECUTE THE INSTRUCTION
RETURN TO STEP ONE FOR NEXT
INSTRUCTION
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19. Running a program
 When you run a code, the code is loaded into memory
 Once the program is in the mm, it can be executed
 The location is determined by the OS
 The memory address of the instruction is loaded into
the PC
 The computer then begin to run the code
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20. EXECUTING AN INSTRUCTION
 We need the instruction
 At the start of the next clock cycle, the CPU issues
request to the memory
 The unit sends the memory address and a request
to read from the main memory
 If the MM is fast, it will not take time.
 For the next instruction, the PC is changed
PC=PC+1
 The type of instruction is determine by the control
unit
 Data is then fetched
 The result of the operation is stored in one of the
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21. 21
 PC=ENTRY POINT
 WHILE (PROGRAM IS RUNNING){
 IR=MEMORY (PC);
 PC=PC+1;
 LET IT=TYPE OF (IR) in;
 IF(IT NEEDS DATA){
 LET ADDR=ADDR in (IR);
 REGISTER (IT)=MEMORY(ADDR);}
 LET TRG = TARGET OF (IR)
 EXECUTE (IT,TRG);}

22. THE SYSTEM BUS MODEL
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CPU
(ALU,
Register, and
control)
I/OMemory
Data Bus
Address
buss
Control
bus
S
y
s
t
e
m
b
u
s

23. SOFTWARE-HARDWARE INTERACTIONS
 Machine language instruction: computer executes
machine language programs mathematically
without understanding them
 Assembler: an assembly language program is
translated into the target computers machine code
by a utility program called an assembler.
 Kernel: the kernel is the central component of most
computer OS. It manages the system resources
and the communication between hardware and
software
 OS: controlling and allocating memory. Networking
and managing files 23

24. 24
Application
Kernel
CPU DeviceMemory

25. HIGH LEVEL LANGUAGE
 Program are portable
 Debugging is easier
 Program are not machine dependent
 Programs are translated using a compiler
 They are understandable
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26. ASSEMBLY LANGUAGE
 Less understandable
 Debugging is complex
 Machine dependent
 Not good for large programs
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27. COMPILER
 A program that translate an instruction from one
computer language to another language for the
computer to understand
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28. QUESTIONS???
THANK YOU FOR YOUR ATTENTION
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