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  • The Motherboard is sometimes called the system board. Many electronic components attach to the motherboard;others are built into it.
  • Computer chips are usually silicon, An integrated circuit contains microscopic pathways that carry electrical currents. Each integrated circuit can contain millions of elements such as resistors, capacitors, and transistors.
  • On larger computers, such as mainframes and supercomputers, the various functions performed by the processor extend over many separate chips and often multiple circuit boards. The term microprocessor is used to refer to a personal computer processor chip.
  • The control unit is like a traffic cop, it interprets each instruction.
  • Today’s computers support a concept Pipelining , it begins fetching the 2 nd instruction before it completes the machine cycle for the 1 st
  • The clock speed determines the pace and is measured by the amount of ticks per second. 1 gigahertz equals one billion ticks/second.
  • ADM which stands for Advanced Micro Devces, is the leading manufacturer of Intelcompatible processors.
  • Chip for chip requires replacing the old chip with a new one. Piggyback requires putting the new chip physically on top of the old one. Daughterboard upgrade requires the new chip to be on an adapter car that plugs into the motherboard.
  • A heat sink can sometimes be metal. Adding new chips cause to much heat because of all the extra power.
  • Floating point is a type of coprocessor that is able to do math. Parallel Processing also divides up the assigned task and solves the problem at the same time.
  • Human speech is called analog. Bits are the smallest unit of data the computer can process. 0s and 1s represent 256 individual characteristics .
  • The American Standard Code for Information Interchange is the most widely used coding system to represent data. The Extended Binary Coded Decimal Interchange Code scheme is used primarily on mainframe computers and high-end servers.
  • 1 or more chips on the motherboard or some other circuit board.
  • The 3 rd category is called the stored programs concept.
  • Volatile is temporary and nonvolatile memory is permanent. RAM is the most common type of volatile memory.
  • When computer is powered on, certain operating system files load into RAM from a storage device such as a hard disk.
  • Dynamic RAM includes also: 1. Synchronous DRAM, which are most faster b/c they are synchronized to the system clock 2. Double Data Rate SDRAM, which are even faster than SDRAM b/c they transfer twice the data for each clock cycle. 3. Rambus DRAM, which are the fastest b/c they use pipelining techniques.
  • SIMM have pins on opposite sides that connect to form a single set of contacts DIMM have pins on opposite sides that don’t connect and form 2 sets of contacts
  • The amount of RAM in computers purchased today ranges from 128 MB to 2 GB. There are RAM guidelines for different types of computer users.
  • When a processor needs an instruction or data, it searches the memory in this order: -L1 -L2 -L3 -RAM -if it still isn’t found it searches hard disk, CD, or DVD
  • Once a programmer writes the microcode onto the PROM chip, it functions like a regular ROM chip. It can’t be erased.
  • Store data on mobile computers, such as PDAs, cellular telephones, printers, digital cameras, music players, and pagers The flash memory chip in a digital cell phone stores names and telephone numbers
  • The flash memory chips that store a computer’s startup info often use CMOS technology.
  • Electricity travels about 1 foot in a nanosecond. Very fast.
  • Sometimes, all functionality is built into the adapter card. With others, a cable connects the adapter card to a peripheral.
  • A modem card is sometimes called an internal modem.
  • All PC Cards conform to standards developed by the Personal Computer Memory Card International Association.
  • Some modems that connect the system unit to a telephone line use a serial port b/c the telephone line expects the data in a specific frequency.
  • Printers connect with a 25 pin female connector.
  • USB supports hot plugging and PLUG and PLAY- can plug into different things and make it easier
  • A system unit with a MIDI port has the capability of recording sounds that have been created with a synthesizer and then processing the sounds to create new sounds.
  • The larger the # of bits handled by the bus, the faster the computer transfers data.
  • A 64-bit processor can manipulate 64 bits at a time.
  • Many newer computers have additional fans near the ports and processor.
  • ch4Schulke

    1. 1. Lisa Schulke The Components of the System Unit Chapter 4
    2. 2. What exactly is the System Unit? <ul><li>A case that contains electronic components used to process data </li></ul><ul><li>Sometimes called the chassis which protects the internal electronic components </li></ul><ul><ul><li>Includes the Motherboard which is the main circuit board of the system unit </li></ul></ul>
    3. 3. More about the Motherboard <ul><li>Many electronic components attach to the board </li></ul><ul><li>Those components include: adapter cards, the processor, and memory chips </li></ul><ul><ul><li>A computer chip is a small piece of semi conducting material which have integrated circuits </li></ul></ul><ul><li>Other components are built into the board </li></ul>
    4. 4. The Processor A component <ul><li>central processing unit </li></ul><ul><li>Interprets & carries out basic instructions that operate a computer </li></ul><ul><li>Manages the computer’s operations </li></ul><ul><li>Contain 2 smaller components </li></ul><ul><ul><li>Control unit </li></ul></ul><ul><ul><li>Arithmetic logic unit </li></ul></ul>
    5. 5. The Control Unit The Arithmetic Logic Unit <ul><li>Directs & coordinates operation </li></ul><ul><li>Interprets each instruction issued by a program & initiates the appropriate action to carry out the instruction </li></ul><ul><li>Arithmetic operations </li></ul><ul><ul><li>Basic calculations </li></ul></ul><ul><li>Comparison operations </li></ul><ul><ul><li>Comparing 1 data to another </li></ul></ul><ul><li>Logical operations </li></ul><ul><ul><li>And, or, and Not </li></ul></ul>
    6. 6. The Machine Cycle: 4 basic operations of a processor <ul><li>Fetching - obtaining a program instruction or data from the memory </li></ul><ul><li>Decoding - translating instructions into signals </li></ul><ul><li>Execute - carries out the commands </li></ul><ul><li>Storing - writing result to memory </li></ul>
    7. 7. Plenty more about processors <ul><li>Contains: </li></ul><ul><ul><li>A register which is storage location that temporarily holds data and instructions </li></ul></ul><ul><ul><li>A system clock that control the timing of computer operations </li></ul></ul><ul><ul><ul><li>Clock speed </li></ul></ul></ul>
    8. 8. Names of Processors <ul><li>Pentium- used by high performance PCs </li></ul><ul><li>Celeron- used by less expensive basic PCs </li></ul><ul><li>Xeon and Itanium- ideal for workstations and low-end servers </li></ul>
    9. 9. Processor Installation and Upgrades <ul><li>3 types of Upgrades </li></ul><ul><ul><li>Chip-for-chip </li></ul></ul><ul><ul><li>Piggyback </li></ul></ul><ul><ul><li>Daughterboard </li></ul></ul>
    10. 10. New chips cause heat <ul><li>A heat sink is a small ceramic component that absorbs and ventilates heat produced by electrical components </li></ul><ul><li>A heat pipe cools processors in notebook computers </li></ul>
    11. 11. Coprocessors and Parallel Processing <ul><li>A coprocessor is a special chip or circuit board that assists the processor in performing tasks </li></ul><ul><ul><li>Floating point has numeric capabilities </li></ul></ul><ul><li>Parallel processing is a method that uses multiple processors to execute a program. </li></ul>
    12. 12. Data Representation <ul><li>Computers communicate digitally and recognize only 2 discrete states: on and off </li></ul><ul><ul><li>recognizes the 2 states by the binary system which only has 2 unique digits( 0 & 1), called bits </li></ul></ul><ul><ul><ul><li>8 bits form a byte </li></ul></ul></ul>
    13. 13. Coding scheme <ul><li>The combinations of 0s and 1s that represent characters are defined by patterns called the coding scheme </li></ul><ul><ul><li>Example: #3 is represented by 00110101 </li></ul></ul><ul><li>The 2 popular coding schemes: </li></ul><ul><ul><li>ASCII and EBCDIC </li></ul></ul>
    14. 14. Memory <ul><li>Consists of electronic components that store instructions waiting to be executed by the processor, data, and the results of processed data (info) </li></ul>
    15. 15. What memory stores? <ul><li>3 basic categories of items: </li></ul><ul><ul><li>The operating system and other system software that control or maintain the computer and its devices </li></ul></ul><ul><ul><li>The application programs that carry out a specific task, such as word processing </li></ul></ul><ul><ul><li>The data being processed by the application programs and resulting information </li></ul></ul>
    16. 16. More about Memory <ul><li>A byte resides temporarily in a location called the address </li></ul><ul><ul><li>An address is a unique number that identifies the location of the byte </li></ul></ul><ul><li>To access data in memory, the computer references the addresses that contain bytes of data </li></ul>
    17. 17. Sizes of Memory <ul><li>A kilobyte is equal to exactly 1,024 bytes </li></ul><ul><li>A megabyte is equal to almost 1 million bytes </li></ul><ul><li>A gigabyte equals almost 1 billion bytes </li></ul><ul><li> 2 types of Memory </li></ul><ul><li>Volatile- when the computer’s power is turned off it loses its contents </li></ul><ul><li>Nonvolatile- does not lose its contents </li></ul>
    18. 18. Ram <ul><li>Stands for Random access memory or main memory </li></ul><ul><li>Consists of memory chips that can be read from and written to by the processor </li></ul><ul><li>It can hold multiple programs simultaneously </li></ul><ul><li>Most Ram is volatile </li></ul>
    19. 19. 2 basic types of ram chips <ul><li>Dynamic Ram </li></ul><ul><ul><li>Must be re-energized constantly or they lose their contents </li></ul></ul><ul><li>Static Ram </li></ul><ul><ul><li>Do not have to be re-energized as often </li></ul></ul><ul><ul><li>More expensive </li></ul></ul><ul><ul><li>Faster and more reliable </li></ul></ul>
    20. 20. Where do RAM chips live? <ul><li>Usually reside on a memory module which is a small circuit board </li></ul><ul><ul><li>Memory slots on the motherboard hold memory modules </li></ul></ul><ul><li>3 types of modules: </li></ul><ul><ul><li>SIMMS (single inline memory module) </li></ul></ul><ul><ul><li>DIMMS (dual inline memory module) </li></ul></ul><ul><ul><li>RIMMS </li></ul></ul>
    21. 21. Ram Configurations <ul><li>The amount of RAM necessary in a computer often depends on the types of software you plan to use </li></ul><ul><li>The more RAM a computer has, the faster it </li></ul><ul><li>A software package will indicate the minimum amount of RAM it requires </li></ul>
    22. 22. Cache: speeds up process <ul><li>Memory cache helps speed the processes of the computer because it stores used instructions and data </li></ul><ul><ul><li>L1 cache has the smallest capacity </li></ul></ul><ul><ul><li>L2 cache has a larger capacity than L1 </li></ul></ul><ul><ul><li>L3 cache exists only with L2 advanced transfer cache </li></ul></ul><ul><li>Disk cache </li></ul>
    23. 23. Read-only memory <ul><li>ROM refers to memory chips storing permanent data </li></ul><ul><li>Data can’t be modified </li></ul><ul><li>ROM is nonvolatile </li></ul><ul><li>Rom chips are called firmware which contain permanently written data/info </li></ul><ul><li>A PROM (programmable) chip is a blank ROM which a programmer can write </li></ul>
    24. 24. Flash Memory <ul><li>A type of nonvolatile memory </li></ul><ul><li>Can be erased electronically and reprogrammed </li></ul><ul><li>Useful for updates </li></ul><ul><li>Flash memory cards store flash memory on a removable device instead of a chip </li></ul>
    25. 25. An aide to chips <ul><li>Complementary metal-oxide semiconductor (CMOS) </li></ul><ul><ul><li>Technology that provides high speeds </li></ul></ul><ul><ul><li>Consumes little power </li></ul></ul><ul><ul><li>Uses battery power to retain info </li></ul></ul>
    26. 26. Memory Access Times <ul><li>Access time is the time it takes the processor to read data/info </li></ul><ul><ul><li>Directly effects how fast the computer runs </li></ul></ul><ul><ul><li>Nanoseconds and MHz are used to state access times </li></ul></ul><ul><ul><li>Accessing data from memory is faster than from hard disk </li></ul></ul>
    27. 27. Expansion slots and adapter cards <ul><li>The slot is a socket that holds adapter card </li></ul><ul><li>An adapter card is a circuit board (expansion card) </li></ul><ul><ul><li>Enhances functions </li></ul></ul><ul><ul><li>Provides connections to peripherals </li></ul></ul><ul><ul><ul><li>A peripheral connects to the system unit and is controlled by the processor </li></ul></ul></ul><ul><ul><ul><ul><li>Examples: modems, printers, scanners </li></ul></ul></ul></ul>
    28. 28. Neat cards <ul><li>A sound card enhances sound by allowing sound to be input thru a microphone and output thru speakers </li></ul><ul><li>A video card converts output info into a signal which displays an image on the screen </li></ul><ul><li>A modem card allows computer to communicate via telephone lines, cable, etc.. </li></ul><ul><li>A network card allows computer to access a network </li></ul>
    29. 29. Pc cards and Flash memory cards <ul><li>A PC Card slot is an expansion slot that holds PC cards </li></ul><ul><ul><li>A PC card adds memory, storage, sound, fax/modem & communications </li></ul></ul><ul><ul><li>PC cards are 1 type of flash memory card </li></ul></ul><ul><ul><ul><li>A flash memory card allows users to transfer data from mobile devices to desktop computers </li></ul></ul></ul>
    30. 30. Ports and Connectors <ul><li>The point where the peripheral connects to the system unit </li></ul><ul><li>Send data </li></ul><ul><li>The term jack is used to identify audio/video ports </li></ul><ul><li>Personal computers have ports in front </li></ul><ul><li>Others have in back </li></ul><ul><li>Joins a cable to a peripheral </li></ul><ul><li>2 genders of cables: </li></ul><ul><ul><li>Male - 1+ exposed pins </li></ul></ul><ul><ul><li>Female -have matching holes to accept the pins </li></ul></ul><ul><li>Same gender can’t connect </li></ul><ul><li>Gender changer - join same gender connectors </li></ul>
    31. 31. Serial Ports <ul><li>Interface that connects a device to the system by transferring bit by bit </li></ul><ul><li>Connect devices that don’t require fast data </li></ul><ul><li>Examples: mouse, keyboard </li></ul><ul><li>The COM port is a type of serial port </li></ul>
    32. 32. Parallel Ports <ul><li>Interface that connects devices by transferring more than 1 bit at a time </li></ul><ul><li>Printers are connected by this port </li></ul><ul><li>Also called a Centronics interface </li></ul>
    33. 33. USB Ports <ul><li>Short for Universal serial bus port </li></ul><ul><li>Can connect up to 127 different peripherals </li></ul><ul><li>Uses only 1 single connector type </li></ul><ul><li>To attach multiple peripherals use Daisy chain </li></ul><ul><ul><li>The 1 st USB device to the USB port on the computer, then the 2 nd connects to 1 st and so on </li></ul></ul><ul><li>USB hub - plugs into USB port and contains multiple USB ports </li></ul>
    34. 34. Special-Purpose Ports <ul><li>Firewire - connect devices that require faster speeds </li></ul><ul><li>Mid i- connects the system unit to a musical instrument </li></ul><ul><li>SCS I (small computer system interface)- connects disk drives and printers </li></ul><ul><li>IrDa - transmits data via infrared light waves </li></ul><ul><li>Bluetooth - transmits data using radio waves </li></ul>
    35. 35. Buses <ul><li>Electrical channels that bits transfer on </li></ul><ul><li>Allows inside and outside devices to communicate with each other </li></ul><ul><li>Consists of 2 parts: </li></ul><ul><ul><li>A data bus transfers actual data </li></ul></ul><ul><ul><li>An address bus transfers info where the data is </li></ul></ul><ul><li>Bus width - the # of bits the computer can transmit at 1 time </li></ul>
    36. 36. Word Size and buses <ul><li>The number of bits the processor can interpret and execute at a give time </li></ul><ul><li>Every bus has a clock speed (hertz) </li></ul><ul><li>2 basic types of buses: </li></ul><ul><ul><li>A system bus connects to main memory </li></ul></ul><ul><ul><li>An expansion bus connects to peripherals </li></ul></ul>
    37. 37. Expansion Bus <ul><li>Communicates with peripherals attached to adapter card </li></ul><ul><li>Types: </li></ul><ul><ul><li>ISA (Industrial Standard Architecture )-most common </li></ul></ul><ul><ul><li>Local - a high speed expansion that connects higher speed devices </li></ul></ul><ul><ul><li>AGP (Accelerated Graphics Port )- designed to improve the speed with 3-D graphics </li></ul></ul><ul><ul><li>FireWire - eliminate the need to install cards </li></ul></ul><ul><li>The expansion bus for a PC Card is the PC Card bus </li></ul>
    38. 38. Power Supply <ul><li>Converts the wall outlet AC power into DC power </li></ul><ul><li>Near the supply is a fan to keep unit cool </li></ul><ul><li>Some external peripherals have an AC adapter , which is an external power supply </li></ul>
    39. 39. Putting it all together <ul><li>Many components of the system unit influence the speed and power of the computer </li></ul><ul><li>These include: </li></ul><ul><ul><li>Type of processor </li></ul></ul><ul><ul><li>Clock speed of the processor </li></ul></ul><ul><ul><li>The amount of RAM </li></ul></ul><ul><ul><li>Clock speed of the bus </li></ul></ul>
    40. 40. Chapter Summary <ul><li>Components of the system unit </li></ul><ul><li>Described how memory stores data/info </li></ul><ul><li>Discussed sequence of operations that occur when a computer executes an instruction </li></ul>