Chapter 02 system unit csc & tts


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Chapter 02 system unit csc & tts

  1. 1. CHAPTER TWO Discovering Computers Fundamentals, 2011 Edition Living in a Digital World
  2. 2. Objectives Overview Differentiate among various styles of system units on desktop computers, notebook computers, and mobile devices Describe the control unit and arithmetic logic unit components of a processor, and explain the four steps in a machine cycle Define a bit and describe how a series of bits represents data Differentiate among the various types of memory 2
  3. 3. Objectives Overview Describe the purpose and types of expansion slots and adapter cards Differentiate between a port and a connector, and explain the differences among a USB port and other ports Describe the types of buses in a computer Understand how to clean a system unit on a computer or mobile device 3
  4. 4. The System Unit • The system unit is a case that contains electronic components of the computer used to process data • Also called the chassis 4
  5. 5. The System Unit • The inside of the system unit on a desktop personal computer includes: Drive bay(s) Power supply Sound card Video card Processor Memory Motherboard ports Bus Line 5
  6. 6. The System Unit • The motherboard is the main circuit board of the system unit – A computer chip contains integrated circuits – Contain expansion slots, processor chips, memory slots. – Also called system board 6
  7. 7. Processor • The processor, also called the central processing unit (CPU), interprets and carries out the basic instructions that operate a computer – Contain a control unit and an arithmetic logic unit (ALU) Multi-core processor Dual-core processor Quad-core processor 7
  8. 8. multi-core processor • A multi-core processor is a single computing component with two or more independent actual processors (called "cores"), which are the units that read and execute program instructions.[1] The instructions are ordinary CPU instructions such as add, move data, and branch, but the multiple cores can run multiple instructions at the same time, increasing overall speed for programs amenable to parallel computing.[ • used across many application domains including general-purpose,embedded, network, digital signal processing (DSP), and graphics. Discovering Computers Fundamentals, 2011 Edition Chapter 4 8
  9. 9. Dual-core processor • A dual-core processor has two cores (e.g. AMD Phenom II X2, Intel Core Duo) Discovering Computers Fundamentals, 2011 Edition Chapter 4 9
  10. 10. Quad-core processor • a quad-core processor contains four cores (e.g. AMD Phenom II X4, Intel's quad-core processors, see i3, i5, and i7 at Intel Core) Discovering Computers Fundamentals, 2011 Edition Chapter 4 10
  11. 11. Processor Click to view Web Link, click Chapter 4, Click Web Link from left navigation, then click Multi-Core Processors below Chapter 4 11
  12. 12. Processor • The control unit is the component of the processor that directs and coordinates most of the operations in the computer • The arithmetic logic unit (ALU) performs arithmetic, comparison, and other operations 12
  13. 13. Processor : Machine cycle ( how processor work) • For every instruction, a processor repeats a set of four basic operations, which comprise a machine 1 cycle: Instruction cycle st cycle (step 1 & 2) 2nd cycle: Execution cycle (step 3 & 4) 13
  14. 14. Processor The system clock controls the timing of all computer operations •The pace of the system clock is called the clock speed, and is measured in gigahertz (GHz) 14
  15. 15. Data Representation Most computers are digital Digital signals are in one of two states: on or off • The binary system uses two unique digits (0 and 1) called bits • Bits – binary digits • Bytes – eight bits grouped together as a unit • Provides enough different combination of 0s and 1s to represent 256 individual characters ( numbers, uppercase, lowercase, punctuation mark and other) 15
  16. 16. Data Representation A computer circuit represents the 0 or the 1 electronically by the presence or absence of an electrical charge Eight bits grouped together as a unit are called a byte. A byte represents a single character in the computer 16
  17. 17. Data Representation Bit 1 1 0 0 1 0 0 1 0 Byte 0 0 1 1 1 0 1 Byte Word 17
  18. 18. Data Representation • ASCII (American Standard Code for Information Interchange) is the most widely used coding scheme to represent data 18
  19. 19. Data Representation 19
  20. 20. Memory • Memory consists of electronic components that store instructions waiting to be executed by the processor, data needed by those instructions, and the results of processing the data • Stores three basic categories of items: The operating system and other system software Application programs Data being processed and the resulting information 20
  21. 21. Memory • Each location in memory has an address • Memory size is measured in kilobytes (KB or K), megabytes (MB), gigabytes (GB), or terabytes (TB) 21
  22. 22. Memory • The system unit contains two types of memory: Volatile memory Nonvolatile memory Loses its contents when power is turned off Does not lose contents when power is removed Example includes RAM Examples include ROM, flash memory, and CMOS 22
  23. 23. Memory: RAM • Also know as primary storage/ primary memory/ main storage/ internal storage/ main memory. • Memory keeps the instruction and data for whatever programs you happen to be using at the moment. • Memory chips that can be read from and written to by processor. • The more RAM a computer has, the faster it responds. 23
  24. 24. Memory 24
  25. 25. Memory • RAM chips usually reside on a memory module and are inserted into memory slots 25
  26. 26. Memory : Volatile memory • Three basic types of RAM chips exist: Dynamic RAM (DRAM) Static RAM (SRAM) Magnetoresistive RAM (MRAM) 26
  27. 27. Memory: Dynamic RAM (DRAM) • Must be continuously refreshed by CPU or it loses its contents. • Used for personal computer memory because of its size and cost advantage. 27
  28. 28. Memory: Static RAM (SRAM) • Retains its contents with intervention from CPU • Faster and more expensive than DRAM • static RAM chips are preferred when energy efficiency is a concern. • Static RAM chips are often used in cars, household appliances and handheld electronic devices 28
  29. 29. Memory • The amount of RAM necessary in a computer often depends on the types of software you plan to use • Memory cache speeds the processes of the computer because it stores frequently used instructions and data 29
  30. 30. Memory: Memory cache 30
  31. 31. Memory: ROM Read-only memory (ROM) refers to memory chips storing permanent data and instructions • It is not lost when computers power is turned off. • Contains program and data permanently recorded into memory at the factory • Cannot be changed by user • Not volatile : contents do not disappear when power is lost. 31
  32. 32. Memory • Flash memory can be erased electronically and rewritten • Used with PDSs, smart phone, printers, digital cameras, automotive devices, audio players, digital voice recorders and pages. 32
  33. 33. Memory : CMOS – CMOS technology provides high speeds and consumes little power – Stand for Complementary Metal-Oxide Semiconductor memory. – Used in some RSM chips, flash memory chips and other types of memory chips. – Uses battery power to retain information when other power is turned off – Stores date, time and computers startup information. 33
  34. 34. Memory • Access time is the amount of time it takes the processor to read from memory – Measured in nanoseconds 34
  35. 35. Expansion Slots and Adapter Cards • An expansion slot is a socket on the motherboard that can hold an adapter card • An adapter card enhances functions of a component of the system unit and/or provides connections to peripherals – Sound card and video card 35
  36. 36. • An ExpressCard module adds memory, storage, sound, fax/modem, communications and other capabilities to notebook computers. 36
  37. 37. Expansion Slots and Adapter Cards • Removable flash memory includes: – Memory cards, USB flash drives, and PC Cards/ExpressCard modules 37
  38. 38. Ports and Connectors A port is the point at which a peripheral attaches to or communicates with a system unit (sometimes referred to as a jack) A connector joins a cable to a port 5 categories of ports: serial ports, parallel port, USB port, FireWire ports, Special-purpose ports. 38
  39. 39. Ports and Connectors 39
  40. 40. Ports and Connectors • On a notebook computer, the ports are on the back, front, and/or sides 40
  41. 41. Ports and Connectors • A USB port can connect up to 127 different peripherals together with a single connector – You can attach multiple peripherals using a single USB port with a USB hub 41
  42. 42. Ports and Connectors • Other types of ports include: Firewire port Bluetooth port SCSI port eSATA port IrDA port MIDI port 42
  43. 43. Ports and Connectors • A port replicator is an external device that provides connections to peripherals through ports built into the device • A docking station is an external device that attaches to a mobile computer or device 43
  44. 44. Buses • A bus allows the various devices both inside and attached to the system unit to communicate with each other – Data bus – Address bus • A computer can have these basic types of buses: – System bus : connect processor and RAM – Backside bus : determines number of bits transmitted at one time. – Expansion bus : allows processor to communicate with peripherals 44
  45. 45. Bays • A bay is an opening inside the system unit in which you can install additional equipment – A drive bay typically holds disk drives 45
  46. 46. Power Supply The power supply converts the wall outlet AC power into DC power Some external peripherals have an AC adapter, which is an external power supply 46
  47. 47. Putting It All Together Home Intel Core 2 Quad or Intel Core 2 Duo or AMD Sempron Minimum RAM: 2 GB Small Office/ Home Office Intel Core i7 or Intel Core i7 Extreme or AMD Athlon X2 or AMD Athlon II X2 Dual-Code Mobile Intel Core i7 Extreme or AMD Turion X2 Minimum RAM: 2 GB Minimum RAM: 4 GB 47
  48. 48. Putting It All Together Power Enterprise Intel Itanium 2 or AMD 6-Core Opteron or Intel Quad Core Xeon Intel Core i7 or Intel Core i7 Extreme or AMD Athlon X2 or AMD Athlon II X2 Dual-Core Minimum RAM: 8 GB Minimum RAM: 4 GB 48
  49. 49. Keeping Your Computer or Mobile Device Clean Clean your computer or mobile device once or twice a year Turn off and unplug your computer or mobile device before cleaning it Use compressed air to blow away dust Use an antistatic wipe to clean the exterior of the case and a cleaning solution and soft cloth to clean the screen 49
  50. 50. Summary Components of the system unit How memory stores data, instructions, and information Comparison of various personal computer processors on the market today Sequence of operations that occur when a computer executes an instruction How to clean the exterior and interior of a system unit 50
  51. 51. CHAPTER TWO Discovering Computers Fundamentals, 2011 Edition Living in a Digital World