The document discusses various components inside a computer system unit including the motherboard, processor, memory, and data representation. It provides details on: 1) The motherboard is the main circuit board that connects all the hardware components. It contains the processor, memory chips, and has expansion slots for adapter cards. 2) The processor, also called the CPU, interprets and carries out instructions to operate the computer. It consists of an arithmetic logic unit for processing and a control unit for managing operations. 3) Data inside computers is represented using binary digits (bits) that can have the value of 0 or 1. Bytes group together 8 bits to represent characters.

1. Week-3 & 4 The System Unit Mother Board CMOS, BIOS Processor Machine Cycle System Clock Multi-Core Processor Basic Unit of Measurement Data Representation Memory RAM

2. System Unit The System Unit is a case which is just like a box made up of a metal or plastic. This casing actually contain the electronic components of a computer used to process data. The casing is some time called Chassis The most important component of this System box is Mother Board. All the components are then installed on this Mother Board. system unit system unit system unit system unit

3. The System Unit What are common components inside the system unit? Processor Memory Adapter cards Sound card Modem card Ports Drive bays Power supply power supply ports drive bays processor memory sound card video card modem card network card

4. Mother Board It is the main circuit board of the system unit. It is the centralized platform where all the hardware components of a computer are connected. Many electronic components are attached to the mother board, others are built-in on it. The processor chips, memory chips & the other components on the motherboard consist one or more chip’s. Most chip’s are not bigger than one-half inch square. processor chip adapter cards memory chips memory slots motherboard Expansion slots for adapter cards

5. CMOS, BIOS Each and every Motherboard has a small battery cell “CMOS memory”. It gives to Motherboard a small amount of power to remember the settings such as hardware configurations, date and time etc BIOS is kind of software which holds the most important data for machine. It informs the PC about the compatibility of Motherboard with different hardware components such as CPU etc… It is the most important component which resides in the ROM CHIP (Read Only Memory) of the Motherboard.

6. Mother Board (Cont’d) Small piece of semi-conducting material on which integrated circuits are etched Two types of packaging for processor and memory chip’s on desktop computers motherboard PGA It holds a larger number of pins, these pins are mounted on the surface of the package. DIP It consist two parallel rows of downward pointing pins that attached to the circuit board. pin grid array (PGA) package holds processor chips dual inline packages (DIP) holds memory chips

7. Processor The Processor is also called Central Processing Unit (CPU). All the CPUs looks very similar, but they are different in the way, they have different numbers of pins and different layouts. The processor significantly impact over all computing power & manages most of computer operations. On larger computers, such as Mini or Mainframe computers, the various functions performed by the processor extend over many separate chips and often on multiple circuit boards. On a personal computer, all function of the processor usually are on a single chip. Some computer manufacturer use the term Microprocessor which refers to a personal computer chip. Most PC’s today use processors manufactured by IntEL, AMD etc.. “ Central Processing Unit (CPU) is an electronic device that interprets and carries out the instructions that operates the computer.

8. Processor (Cont’d)

9. Processor ( Cont’d ) The combination of Arithmetic Logic Unit and Control Unit is called as Central Processing Unit (CPU). OR The two main parts of CPU are ALU & CU.

10. Processor ( Cont’d ) ARITHMETIC LOGIC UNIT (ALU) This component of the computer is responsible for the actual processing. This component is capable to perform all types of arithmetic operations such as addition, subtraction, multiplication and division etc. Also it is capable to perform logical operations such as AND, OR etc. it is capable of comparison as well. The ALU is connected to a set of registers—small & faster memory areas in the CPU, which hold data and program instructions while they are being processed.

11. Processor ( Cont’d ) Registers are the part of the processor, not a part of memory or storage devices. It contain different type of registers, each with a specific storage functions. E.g. General purpose registers used for arithmetic operations & data movement. AX, BX, CX, DX Register function includes Storing the location from where an instruction is fetched, Storing the location while the CU encode/decode it, Storing data while the ALU compute it and Storing the results after a calculation. Today, most PCs have 32-bit registers, mean the CPU can process four bytes of data at one time. Register sizes are rapidly growing to 64 bits.

12. Processor ( Cont’d ) ALU Operations List Logical Operations  ,  less than or equal to, not less than or equal to ^ Raise by a power  ,  greater than or equal to, not greater than or equal to  Divide <, < less than, not less than x Multiply >, > greater than, not greater than  Subtract  ,  equal to, not equal to + Add Arithmetic Operations

13. Processor (Cont’d) CONTROL UNIT (CU) This unit is responsible for the overall supervision of the computer system. It does not perform the actual processing but by reading and interpreting the instructions contained in a program, Control Unit (CU) directs other unit of the system to perform a specific task. Control unit (CU) behaves like a traffic police instructor. It manages the functions performed by different parts of computer. It controls and coordinates the entire computer system, just the brain directs the human body. It is responsible to accept data from input device and send it to the memory, from memory to ALU, finally CU sent back the results and store in the memory, until the results are released to an output device.

14. Machine Cycle The CPU follows a set of steps-called a machine cycle-for each instruction it carries out. By using a technique called pipelining, many CPUs can process more than one instruction at a time. Four operations of the CPU comprise a machine cycle Step 2. Decode Translate instruction into commands Processor Control Unit Memory ALU Step 1. Fetch Obtain program instruction or data item from memory Step 4. Store Write result to memory Step 3. Execute Carry out command

15. System Clock Each tick is a clock cycle Pace of system clock is clock speed Most clock speeds are in the gigahertz (GHz) range (1 GHz = one billion ticks of system clock per second) Processor speed can also be measured in m illions of i nstructions p er s econd (MIPS) or in FLOPs Controls timing of all computer operations Generates regular electronic pulses, or ticks, that set operating pace of components of system unit

16. Heat Sink Heat sink — component with fans that cools processor heat sink fan heat sink

17. Parallel Processing Control Processor Results combined Using multiple processors simultaneously to execute a program faster Requires special software to divide problem and bring results together Processor 1 Memory Processor 2 Memory Processor 3 Memory Processor 4 Memory

18. Multi-Core Processor A Multi-Core Processor is a processing system composed of two or more independent cores. The cores are typically integrated onto a single integrated circuit die(known as a chip multiprocessor or CMP). Core Basic processing area of a computer processor Die A die in the context of integrated circuits is a small block of semiconducting material, on which a given functional circuit is fabricated. A medium-scale integrated circuit die

19. Multi-Core Processor (Cont’d) A Dual-Core and Core 2 Duo Processor contains two cores, and a Quad-Core Processor contains four cores. A Multi-core processor implements multiprocessing in a single physical package. Cores in a multi-core device coupled together tightly. Cores may or may not share caches. Dual Core and Core 2 Duo’s are both dual core processor. Core2 duo only takes advantage because The Core 2 Duo has the same L2 cache but it has more cache size than a Dual core. However, There are architectural changes to the silicon that give the Core 2 Duo more sophisticated processing. The single- and dual-core models are single-die, whereas the quad-core models comprise two dies, each containing two cores, packaged in a multi-chip module.

20. Basic Units Of Measurement BIT BInary digiT Smallest unit of measurement Two possible values 0 & 1 ON OFF or BYTE 8 bits

21. Data Representation Recognize only two discrete states: on or off Use a binary system to recognize two states Use Number system with two unique digits: 0 and 1, called bits (short for binary digits) Most computers are digital

22. Data Representation (Cont’d) Eight bits grouped together as a unit Provides enough different combinations of 0s and 1s to represent 256 individual characters Numbers Uppercase and lowercase letters Punctuation marks

23. Data Representation (Cont’d) 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 Unicode —coding scheme capable of representing all world’s languages ASCII Symbol EBCDIC 00110000 0 11110000 00110001 1 11110001 00110010 2 11110010 00110011 3 11110011

24. Data Representation (Cont’d) How is a letter converted to binary form and back? Step 2. An electronic signal for the capital letter D is sent to the system unit. Step 3. The signal for the capital letter D is converted to its ASCII binary code (01000100) and is stored in memory for processing. Step 1. The user presses the capital letter D (shift+D key) on the keyboard. Step 4. After processing, the binary code for the capital letter D is converted to an image, and displayed on the output device.

25. Basic Units Of Measurement ( Processor And Memory Speed ) Millisecond (ms) – a thousandth of a second (1/1,000 = 10 -3 ) Microsecond (µs) - a millionth of a second (1/1,000,000 = 10 -6 ) Nanosecond (ns) – a billionth of a second (1/1,000,000,000 = 10 -9 ) Large Units Of Measurement (Memory, Storage) Note: powers of two are used because computer memory and storage are based on the basic unit (bit). Kilobyte (KB) – a thousand bytes (1,024 = 2 10 ) Megabyte (MB) -1,024 KB - a million (1,048,576 = 2 20 ) Gigabyte (GB) –1,024 MB - a billion (1,073,741,824 = 2 30 ) Terabyte (TB) – a trillion (1,099,511,627,776 = 2 40 )

26. Memory The electronic component which provides storage capability to a computer is called Memory. Memory contains one or more sets of chips that store data/program instructions need processing, either temporarily or permanently. All the computers which are used today needs memory or storage capability. The CPU accesses each location in memory by using a unique number, called the memory address. Each byte stored in unique location called an address , similar to addresses on a passenger train Seat #2B4 Seat #2B3

27. Memory (Cont’d) The are two types of Memory Random Access Memory Read Only Memory

28. Random Access Memory RAM is also called volatile memory and Keeps the information for a shorter period of time because RAM Lost information if powered off or the computer is shutdown. RAM store data or instructions, the computer then uses these instructions to perform any processing work. The contents of RAM change rapidly and often. Typical ranges from Mega Bytes to Giga Bytes Random Access means direct access to any part of memory The more RAM a computer has, the faster it responds Also called main memory or primary storage Most RAM is volatile , it is lost when computer’s power is turned off Memory chips that can be read from and written to by processor

29. How do program instructions transfer in and out of RAM? Step 1. When you start the computer, certain operating system files load into RAM from the hard disk. The operating system displays the user interface on the screen. Operating system instructions Operating system interface Web browser program instructions are removed from RAM Web browser window no longer is displayed on desktop Step 2. When you start a word processing program, the program’s instructions load into RAM from the hard disk. The word processing program, along with the Web Browser and certain operating system instructions are in RAM. The word processing program window is displayed on the screen. Step 3. When you quit a program, such as the Web browser, its program instructions are removed from RAM. The Web browser no longer is displayed on the screen. Word processing program instructions Word processing program window RAM RAM

30. Where does Memory Reside? Resides on small circuit board called memory module Memory slots on motherboard hold memory modules memory chip memory slot dual inline memory module