1 MT-210 Computer Fundamentals Tutorial 8 ( part 1 ) Group 17 Tutor : Kenny YUEN Chapter 5 (Set Book) Computer Architecture

2  It refers to the design & construction of a computer system Computer Architecture

3 Motherboard ( 底板 ) or main board  Provide sockets for chips (IC), slots for small circuit board, and circuitry that connecting these components  Provide expansion slots for connection with peripheral devices  such as EISA, PCI & APG slot

4  Integrated Circuit (IC)  A thin slice of silicon crystal packed with microscopic circuits elements such as :  Wires, Transistors, Capacitors, and resistors  Chip Packages, including  DIP (dual in-line pin),  DIMM (dual in-line memory module)  PGA (pin-grid array)  SEC (single edge contact)

5 Data Representation  An Analog device operates on continuously varying data  A Digital device works with discrete number,  digital computer represent numeric data using Binary Number system  Which has only 2 digits : [ 0 ] and [ 1 ]  " Character data " composed of letter, symbol, & numeral that will not be used in arithmetic operations  digital computers represent character data using codes and "Code Set".  ASCII := A merican S tandard C ode for I nformation I nterchange  EBCDIC := E xtended B inary- C oded D ecimal I nterchange C ode  Most micro-computers use ASCII code to represent character data  Some mini, mainframe computers use EBCDIC code to represent character data

6 Code Sets

7 Data Transport  [ Data bus ] is an electronic pathway or circuit that links the chips on the motherboard for data to travel  The bus contains data line and address line  [ data line ] : carry the signals that represent data  [ address line ] : carry the signals that specify where the computer can find the data that it is supposed to process Memory  There are 2 major categories : Primary & Secondary  There are 4 major types of memory :  RAM : R andom A ccess M emory  Virtual Memory : by the use of hard disk  CMOS : C omplementary M etal O xide S emiconductor  ROM : R ead O nly M emory

8 RAM  Temporarily holds {data, instructions } before/after it is processed until the computer is turn off.  Require power to hold. No power, then no data.  A reusable computing resource as the contents can be changed Virtual memory  Use space on hard disk, as an extension of RAM, to simulate RAM.  Works slower than RAM because  RAM is electronic device  Hard disk is mechanical device  Like RAM : no power, then data in virtual memory become in-accessible ROM  One or more chips containing instructions that help a computer prepare for processing tasks  Instructions in ROM are permanent  The only ways to remove instructions is to remove that chips  Holds Basic I/O system (BIOS) for PC bootstrap & tells the computer how to access disk drives and other peripheral devices CMOS  More permanent then RAM but less permanent then ROM  Stores hardware configuration, which can be changed  Memory is powered by battery

9 Central Processing Unit (CPU)  The circuitry in a computer that execute instruction to process date  It takes instruction/data from RAM, process instructions then places the results back into RAM

10 There are 2 main parts : 1/. Arithmetic Logic Unit (ALU),  performs arithmetic operations such as addition & subtraction  performs Logical operations such as comparing 2 numbers to check if they are the same  Use registers to hold data that is being processed  The result of the ALU will be kept in accumulator,

11 2/. Control Unit (CU),  direct & control processing  Use instruction pointer to keep track of instruction sequence  Retrieve each instruction in sequence from RAM and place it in instruction register  Interpret the instruction &  may send signal to data bus to :  fetch data from RAM  to the ALU to perform a process

12 Instructions  tells the computer to perform arithmetic, logical, or control operation  It has 2 parts  [ op code ] = "operation code", a command word for an operation  Such as add, compare, or jump  [ operands ] specify the data or address of the data for the operation  [ Instruction cycle ] as, shown in margin, refers to the process that a computer executes a single instruction

13 Processing Instructions

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15 Performance Factors System Clock  generates pulses to establish the timing for all system operations,  sets speed/frequency for data transport & instruction execution  Thus, limits no of instructions to be completed in a fixed time slot Word size  The no. of bits a CPU can manipulate at one time  Based on size of registers in the CPU & no. of data line in the bus Cache  "RAM cache" or "cache memory", high speed memory that give the CPU more rapid access to data  when an instruction calls for data, the CPU 1 st checks if it is in cache.  If yes, it takes it from cache. Otherwise, it fetch it from RAM which takes longer  Generally, more cache means faster processing

16 Register Cache CMOS, ROM RAM  Primary Storage  Secondary Storage  Hard to increase  Easy to increase  Performance  Cost (bit / $ ) Decreasing Increasing  Storage Size Punch card, Tape Floppy, Zip disk, CD, DVD

17 Instruction Set Complexity CISC (Complex Instruction Set Computer )  Complex instructions are provided in this kind of machine, however  20% of the instructions of a CICS machine do about 80% of the work RISC (Reduced Instruction Set Computer )  Has limited set of instructions that it can perform very quickly  In theory a RISC machine is faster than CISC machine for most tasks  Scientists believe that a balance or hybrid of CISC & RISC technologies produces the most efficient and flexible computer

18 Pipelining  To speed up the processing  A processor can begin executing part of the next instruction(s) before the current instruction-1 completed, as shown below Time

19 Parallel Processing  these are Parallel Computers  Increase the amount of processing that a computer can accomplish in a specific amount of time

20 Input & Output (IO)  Refers to collecting data for the microprocessor to manipulate, and transporting results to display, print and storage devices  [ Expansion Bus ] is a segment of the data bus that transports data between RAM and peripheral devices

21 Expansion Slots & Cards  Expansion Slot is a long, narrow socket on the motherboard, where you can plug your expansion cards  expansion card / controller card is a small circuit board that provides a computer with the ability to control a storage, input, or output devices  Examples  Sound card  Modem card  LAN card  Capture card  AGP graphic card

22 ISA  Industry Standard Architecture  An obsolete technology, used for some modem and other relatively slow devices PCI  Peripheral Component Interconnect  Offers faster transfer speeds and a 64-bit data bus  Houses graphics card, sound card, video capture card, modem or network interface card (LAN card) AGP  Accelerated Graphics Port  Primarily used for graphics cards,  Faster than a PCI slot  Provides a high speed data pathway for 3D graphics

23 Expansion port & cable  Expansion Port is any connector that passes data in & out of a computer or peripheral device  Ports are sometimes called "jacks" or "connector"

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