The document discusses the key components that make up a computer system unit. It describes the central processing unit, memory components like RAM and ROM, the motherboard, buses that transfer data, expansion cards and ports that connect peripheral devices. The system unit houses the electronic components and motherboard that organize the computer's activities.

1. The Central Process Unit Chapter 4 B.M.H

2. Learning Objectives System Unit Microprocessor Memory RAM ROM Bus line System bus Expansion buses Expansion slot Expansion cards MIU

3. The System Unit ; The case that houses the electronic components of the computer system Components Motherboard The main system unit component Storage Devices Hard drive, floppy drive, CD/DVD-ROM drive Power Supply Wires and Ribbon Cables MIU

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5. Motherboard Called the main circuit board The flat circuit board within the personal computer housing that hold the computer circuitry A mass of chips and connections that organize the computer ’ s activities MIU

6. Motherboard Components Microprocessor ; the most important component Memory chips RAM ROM Bus line System bus Expansion buses Expansion slots Expansion cards MIU

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9. Microprocessor Central processing unit on a chip Called Logic chip when it is used to control specialized devices. key components Control unit Arithmetic/logic unit Register System clock MIU

10. Microprocessor MIU

11. Microprocessor Contain tiny transistors The basic building block of the microprocessor Today, millions of transistors Electronic switches that may or may not allow current to pass through If current passes through, the switch is ( ), representing a ( ) bit If current does not pass through, the switch is ( ), representing a ( ) bit The combination of transistors Stand for combination of ( ) Represent digits, letter, and special characters MIU Refer to Computers7_ch4_2_1 Computers7_ch4_2_2

12. Microprocessor Pentium chip By Intel The current workhorse in the PC market Includes multimedia instructions PowerPC family of chips -- non-Intel By Apple, IBM, and Motorola Manufactured by both IBM and Motorola primary use : Apple Macintosh family of PCs Alpha -- non-Intel Produced by Compaq Used in high-end servers and workstations MIU

13. Memory Component Evolved from primitive vacuum tubes Today ’ s modern memory ; Semiconductor Advantage reliability compactness low cost lower power usage Volatile Require continuous electric current to represent data Monolithic all the circuits on single chip together constitute an inseparable unit of storage MIU

14. Semiconductor Memory Thousand of very small circuits-pathways for electric currents-on a silicon chip Each circuit on a chip be in one of two states, on or off two states : represent the binary digits 1 and 0 these digits : combined to represent ( c~ ) thus makes the memory chip a storage bin for data and instructions MIU

15. Semiconductor Memory CMOS one important type of semiconductor design C omplementary M etal O xide S emiconductor the design is noted for using relatively little electricity CMOS RAM : In PC, one use for CMOS a small amount of memory that, thanks to battery power, retains data when the computer is shut off to store information your computer needs when it boots up, such as time, date, and hardware configuration data when the computer is running, it can be updated MIU

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17. RAM (Random Access Memory) volatile its contents are lost once the power is shut off Static RAM(SRAM) will retain its contents without intervention from the CPU as long a power is maintained much faster than DRAM Dynamic RAM(DRAM) must be constantly refreshed (recharged) by the CPU or it will lose its contents used for most PC memory because of its size and cost advantages Synchronous DRAM (SDRAM) a faster type of DRAM, used in most PCs today Rambus DRAM(RDRAM) faster than SDRAM MIU

18. DRAM MIU

19. RAM RAM packaged on circuit boards SIMMs (single in-line memory modules) memory chips are installed on one side of the board DIMMs (dual in-line memory modules) memory chips are installed on both sides of the board  Motherboard design determines the maximum amount of memory  For increasing the PC's RAM buy extra memory modules and plug into your computer's motherboard MIU

20. ROM (Read-only memory ) Contain programs and data that are permanently recorded into this type of memory at the factory Nonvolatile ex) the boot routine is stored in ROM PROM (programmable read-only memory) By ROM burners the instructions within it can be changed MIU

21. Bus Line (Bus) A set of parallel electrical paths that transport electrical signals copper tracing on the surface of the motherboard Types System bus transports data between the CPU and memory Expansion buses Connect to expansion slots, and ports on the motherboard MIU P4-113

22. Bus Bus width the number of bits of data that can be carried at one time indicates the number of electrical paths the greater the width, the more data can be carried at a time . the width of system bus depend on the CPU design, normally, the same as the CPU's word size Bus speed Measured in megahertz (MHz) The faster the bus speed, the faster data travels through the system MIU

23. Expansion Boards interface cards or adapter cards Connect various peripheral devices to a computer by plugging them into expansion slots on the motherboard Provide external connectors, called ports To plug in peripherals such as a printer, a mouse, and a keyboard MIU

24. Port Serial ports Transmit data one bit at a time, similar to cars on a one-lane road Are typically used for slow-speed devices such as the mouse and keyboard Parallel ports Transmit groups of bits together Are used for faster devices such as printers and scanners MIU

25. Serial port VS. Parallel port Serial Port MIU Parallel Port Computer / Main Board - Port

26. Common Buses and Ports on PCs Industry Standard Architecture (ISA) bus Is used for slow-speed devices such as the mouse and modem Peripheral Component Interconnect (PCI) bus A high-speed bus used to connect devices such as hard disks and network cards Accelerated Graphics Port (AGP) Designed to provide a dedicated connection between memory and an AGP graphics card Universal Serial Bus (USB) Through a port on the back of the system unit Connect and disconnect them without turning off the power IEEE 1394 bus A highly speed bus that is normally used to connect video equipment to a computer PC Card bus The slot accepts credit card-sized PC Card devices MIU

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