MT-210 Computer Fundamentals

1. MT-210 Computer Fundamentals Chapter5 (Set Book) Computer Architecture Tutorial 8 ( part 1 ) Group 17 Tutor : Kenny YUEN http://learn.ouhk.edu.hk/~t441063

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

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 := American Standard Code for Information Interchange • EBCDIC := Extended Binary-Coded DecimalInterchange Code • Most micro-computers use ASCII code to represent character data • Some mini, mainframe computers use EBCDICcode 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 : Random Access Memory • Virtual Memory : by the use of hard disk • CMOS : Complementary Metal Oxide Semiconductor • ROM : Read Only Memory

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

15. Performance Factors • SystemClock • 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 1st 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. Decreasing • Primary Storage • Secondary Storage • Hard to increase • Easy to increase Register Cache • Performance • Cost (bit / $ ) Increasing CMOS, ROM RAM • Storage Size Floppy, Zip disk, CD, DVD Punch card, Tape

17. Instruction Set Complexity • CISC (ComplexInstruction 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 (ReducedInstruction 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

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"