Computer Hardware C HAPTER 2

2 Chapter 2: Computer Hardware2 Chapter Contents  Section A: Data Representation and Digital ElectronicsData Representation and Digital Electronics  Section B: Microprocessors and MemoryMicroprocessors and Memory  Section C: Storage DevicesStorage Devices  Section D: Input and Output DevicesInput and Output Devices

2 SECTION A Chapter 2: Computer Hardware3 Section A: Data Representation and Digital Electronics  Data Representation  Quantifying Bits and Bytes  Digital Electronics

2 Chapter 2: Computer Hardware4 Data Representation  Process of transforming diverse data into a form computers can use for processing  Digital devices work with distinct and separate data  Analog devices work with continuous data

2 Chapter 2: Computer Hardware5 Data Representation  Numeric data –Binary number system  Character data –ASCII, Extended ASCII, and Unicode (not used in arithmetic operations)  Digitizing is the process of converting analog data into digital format  File headers contain information about the code used to represent file data

2 Chapter 2: Computer Hardware6 Data Representation

2 Chapter 2: Computer Hardware7 Quantifying Bits and Bytes

2 Chapter 2: Computer Hardware8 Digital Electronics  Bits take the form of electrical pulses that can travel over circuits  System unit

2 Chapter 2: Computer Hardware9 Digital Electronics  An integrated circuit (computer chip) is a super-thin slice of semiconducting material packed with microscopic circuit elements

2 Chapter 2: Computer Hardware10 Digital Electronics  The computer’s main circuit board is called the system board, or motherboard

2 SECTION B Chapter 2: Computer Hardware11 Section B: Microprocessors and Memory  Microprocessor Basics  Microprocessor Performance Factors  Today’s Microprocessors  Random Access Memory  Read-only Memory  CMOS Memory  Buying a Computer

2 Chapter 2: Computer Hardware12 Microprocessor Basics  A microprocessor is an integrated circuit designed to process instructions –ALU –Registers –Control unit –Instruction set (list of instructions a microprocessor can perform)

2 Chapter 2: Computer Hardware13 Microprocessor Performance Factors  Microprocessor clock (sets pace for executing instructions) –Megahertz (millions of cycles per second) –Gigahertz (billions of cycles per second)  Word size (# of bits a processor can manipulate at a time)  Cache (high speed memory where a processor can access data quicker than memory located elsewhere) –Level 1 cache (L1) –Level 2 cache (L2)  CISC vs. RISC technology –CISC- complex instruction set computer –RISC- reduced instruction set computer. RISC is faster than CISC

2 Chapter 2: Computer Hardware14 Microprocessor Performance Factors  Serial processing- processor completes all steps in the instruction cycle before it begins to execute the next instruction –Pipelining  Parallel processing

2 Chapter 2: Computer Hardware15 Microprocessor Performance Factors  Dual core processors contain the circuitry for two microprocessors  Benchmark tests gauge the overall speed of a microprocessor  A microprocessor can operate at full efficiency only if all components in the computer can handle the faster speeds.

2 Chapter 2: Computer Hardware16 Today’s Microprocessors

2 Chapter 2: Computer Hardware17 Random Access Memory  Random Access Memory is a temporary holding area for data, application program instructions, and the operating system

2 Chapter 2: Computer Hardware18 Random Access Memory  Microscopic capacitors hold the bits that represent data  Most RAM is volatile –Requires electrical power to hold data –Usually consists of several chips

2 Chapter 2: Computer Hardware19 Random Access Memory  RAM capacity is expressed in megabytes or gigabytes  Personal computers typically feature between 128 MB and 2 GB of RAM  An area of the hard disk, called virtual memory, can be used if an application runs out of allocated RAM

2 Chapter 2: Computer Hardware20 Random Access Memory  RAM speed is often expressed in nanoseconds or megahertz  SDRAM is fast and relatively inexpensive –DDR  RDRAM is more expensive, and usually found in high-performance workstations  “Waiting room” for the processor

2 Chapter 2: Computer Hardware21 Read-Only Memory  ROM is a type of memory circuitry that holds the computer’s startup routine –Permanent and non-volatile  The ROM BIOS tells the computer how to access to hard disk, find the operating system, and load it into RAM

2 Chapter 2: Computer Hardware22 CMOS Memory  Stores basic system information  More permanent than RAM, and less permanent than ROM  Requires very little power to hold data

2 Chapter 2: Computer Hardware23 Buying a Computer  Assess your budge  Think about how you plan to use your computer  Look at ads and visit online computer stores

2 SECTION C Chapter 2: Computer Hardware24 Section C: Storage Devices  Storage Basics  Floppy Disk Technology  Hard Disk Technology  Tape Storage  CD and DVD Technology  Solid State Storage

2 Chapter 2: Computer Hardware25 Storage Basics  A storage medium contains data  A storage device records and retrieves data from a storage medium –Data gets copied from a storage device into RAM, where it waits to be processed –Processed data is held temporarily in RAM before it is copied to a storage medium

2 Chapter 2: Computer Hardware26 Storage Basics  Magnetic storage stores data by magnetizing microscopic particles on the disk or tape surface

2 Chapter 2: Computer Hardware27 Storage Basics  Optical storage stores data as microscopic light and dark spots (land and pits) on the disk surface –CD and DVD storage technologies

2 Chapter 2: Computer Hardware28 Storage Basics  Solid state storage technology stores data in a non-volatile, erasable, low-power chip –Some solid state storage requires a card reader to transfer data to or from a computer –Faster than optical or magnetic storage

2 Chapter 2: Computer Hardware29 Storage Basics Most desktop computers have several drive bays, some accessible from outside the case, and others—designed for hard disk drives—without any external access. Empty drive bays are typically hidden from view with a face plate. CLICK TO START

2 Chapter 2: Computer Hardware30 Storage Basics  Versatility  Durability  Speed –Access time (often measured in milliseconds and is how long it takes a computer to locate data on storage medium and read it) –Random vs. sequential access –Data transfer rate  Capacity –Kilobytes (KB), megabytes (MB), and gigabytes frequently used today

2 Chapter 2: Computer Hardware31 Floppy Disk Technology  Used for standard HD DS disks and Zip disks

2 Chapter 2: Computer Hardware32 Hard Disk Technology Hard disk platters are sealed inside the drive case or cartridge to prevent dust and other contaminants from interfering with the read-write heads. CLICK TO START

2 Chapter 2: Computer Hardware33 Hard Disk Technology  A controller positions the disk and read-write heads to locate data –SATA –Ultra ATA –EIDE –SCSI  Not as durable as many other storage technologies –Head crash

2 Chapter 2: Computer Hardware34 Tape Storage  A tape backup stores a copy of the data on a hard disk on a magnetic tape  A tape is a sequential storage medium

2 Chapter 2: Computer Hardware35 CD and DVD Technology  A CD can hold up to 80 minutes of music or 700 MB of data  A DVD can hold about 4.7 GB of data  A double-layer DVD can store 8.5 GB of data  HD-DVDs can store 15 GB  Blu-ray DVDs can store 25 GB

2 Chapter 2: Computer Hardware36 CD and DVD Technology  CD-DA  DVD-Video  CD-ROM  DVD-ROM  CD-R  DVD+R or DVD-R  CD-RW  DVD+RW or DVD-RW

2 Chapter 2: Computer Hardware37 CD and DVD Technology

2 Chapter 2: Computer Hardware38 Solid State Storage (Portable)  USB flash drive  CompactFlash (CF) cards  MultiMedia cards (MMC)  SecureDigital (SD)  SmartMedia (least durable)

2 SECTION D Chapter 2: Computer Hardware39 Section D: Input and Output Devices  Basic Input Devices  Display Devices  Printers  Installing Peripheral Devices

2 Chapter 2: Computer Hardware40 Basic Input Devices  Keyboard  Pointing device –Pointing stick –Trackpad –Trackball –Joystick

2 Chapter 2: Computer Hardware41 Display Devices  A CRT display device uses a bulky glass tube (least expensive)  An LCD manipulates light within a layer of liquid crystal cells  Plasma screen technology illuminates lights arranged in a panel-like screen  On most monitors, the viewable image does not stretch to the edge of the screen

2 Chapter 2: Computer Hardware42 Display Devices  Viewable image size  Dot pitch  Viewing angle width  Refresh rate  Color depth  Resolution –VGA, SVGA, XGA, SXGA, and UXGA

2 Chapter 2: Computer Hardware43 Display Devices

2 Chapter 2: Computer Hardware44 Display Devices  Graphics circuitry generates the signals for displaying an image on the screen –Integrated graphics –Graphics card

2 Chapter 2: Computer Hardware45 Printers  An ink-jet printer has a nozzle-like print head that sprays ink onto paper  A laser printer works like a photocopier

2 Chapter 2: Computer Hardware46 Printers Laser printers are a popular technology when high-volume output or good-quality printouts are required. CLICK TO START

2 Chapter 2: Computer Hardware47 Printers  Dot matrix printers produce characters and graphics by using a grid of fine wires –The wires strike a ribbon and the paper

2 Chapter 2: Computer Hardware48 Printers  Other printer technologies include solid ink printers, thermal transfer printers, and dye sublimation printers  Printer features –Resolution –Print speed –Duty cycle –Operating costs –Duplex capability –Memory

2 Chapter 2: Computer Hardware49 Installing Peripheral Devices  The data bus moves data within the computer  The expansion bus is the segment of the data bus that extends between RAM and peripheral devices  Expansion cards are small circuit boards that give the computer additional capabilities –Expansion slot ISA (Old technology. Slower devices, not found on most new computers) PCI (32 or 64 bit. Graphics cards, network cards, and more) AGP (Primarily used for graphics cards) PCMCIA (Used in notebook computers)

2 Chapter 2: Computer Hardware50 Installing Peripheral Devices An expansion card simply slides into an expansion slot and is secured with a small screw. Before you open the case, make sure you unplug the computer and ground yourself—that’s technical jargon for releasing static electricity by using a special grounding wristband or by touching both hands to a metal object. CLICK TO START

2 Chapter 2: Computer Hardware51 Installing Peripheral Devices  An expansion port passes data in and out of a computer or peripheral device  Peripheral device may include the Plug and Play feature, or require a device driver

2 Chapter 2: Computer Hardware52 Installing Peripheral Devices

C HAPTER 2 C OMPLETE Computer Hardware