Chapter 2 Computer Hardware Learning Objectives LO2.1: Understand how data is represented to a computer LO2.2: Identify the parts inside the system unit LO2.3: Explain how the CPU works LO2.4: Describe different types of storage systems LO2.5: Identify and describe common input devices LO2.6: Identify and describe common output devices CMPTR Chapter 2: Computer Hardware 2 1
LO2.1: Digital Data Representation Virtually all computers today are digital computers. The 0s and 1s used to represent data can be represented in a variety of ways. CMPTR Chapter 2: Computer Hardware 3 LO2.1: Digital Data Representation CMPTR Chapter 2: Computer Hardware 4 2
LO2.2: Inside the System Unit The system unitis the main case of a computer. Topics Covered: The Motherboard The Power Supply The CPU Memory Expansion Slots, Expansion Cards, and ExpressCard Modules Buses Ports and Connectors CMPTR Chapter 2: Computer Hardware 5 The Motherboard All devices used with a computer need to be connected via a wired or wireless connection to the motherboard. External devices typically connect to the motherboard by plugging into a port. CMPTR Chapter 2: Computer Hardware 6 3
The Motherboard CMPTR Chapter 2: Computer Hardware 7 The Power Supply The power supply inside a desktop computer connects to the motherboard to deliver electricity to the computer. Portable computers almost always contain a rechargeable battery pack to power the computer when it is not connected to a power outlet, as well as an external power supply adapter that connects the computer to a power outlet to recharge the battery when needed. CMPTR Chapter 2: Computer Hardware 8 4
The CPU The central processing unit (CPU or processor) is a computer chip that performs the calculations and comparisons needed for processing; it also controls the computer s operations. Many CPUs today are multicore CPUs; that is, CPUs that contain the processing components or cores of multiple independent processors in a single CPU. CMPTR Chapter 2: Computer Hardware 9 The CPU The CPU clock speedmeasures of the number of instructions that can be processed per second. Cache memory is a special group of very fast memory circuitry located on or close to the CPU that is used to speed up processing by storing the data and instructions that may be needed next by the CPU in handy locations. CMPTR Chapter 2: Computer Hardware 10 5
Memory Memory is chips located inside the system unit that the computer uses to store data and instructions while it is working with them. RAM (random access memory) is used to store the essential parts of the operating system while the computer is running, as well as the programs and data that the computer is currently using. CMPTR Chapter 2: Computer Hardware 11 Memory A register is high-speed memory built into the CPU that temporarily stores data during processing. ROM (read-only memory) consists of nonvolatile chips that permanently store data or programs. Flash memory consists of nonvolatile memory chips that can be used for storage by the computer or the user. Flash memory chips have begun to replace ROM for storing system information. CMPTR Chapter 2: Computer Hardware 12 6
Expansion Slots, Expansion Cards, and ExpressCard Modules Most desktop computers come with a few empty expansion slots so new expansion cards can be added as needed. Today most notebook and netbookcomputers use the newer ExpressCard modules. CMPTR Chapter 2: Computer Hardware 13 Buses A bus is an electronic path over which data can travel. CMPTR Chapter 2: Computer Hardware 14 7
Buses CMPTR Chapter 2: Computer Hardware 15 Ports and Connectors Ports are the connectors located on the exterior of the system unit that are used to connect external hardware devices. Each port is attached to the appropriate bus on the motherboard so that when a device is plugged into a port, the device can communicate with the CPU and other computer components. CMPTR Chapter 2: Computer Hardware 16 8
Ports and Connectors CMPTR Chapter 2: Computer Hardware 17 LO2.3: How the CPU Works Topics Covered: Typical CPU Components The System Clock and the Machine Cycle CMPTR Chapter 2: Computer Hardware 18 9
Typical CPU Components The key element of the CPU is the transistor a device made of semiconductor material that controls the flow of electrons inside a chip. The arithmetic/logic unit (ALU) is the section of a CPU core that performs arithmetic involving integers and logical operations. Arithmetic requiring decimals is usually performed by the floating point unit (FPU). CMPTR Chapter 2: Computer Hardware 19 The System Clock and the Machine Cycle In order to synchronize all of a computer s operations, a system clock a small quartz crystal located on the motherboard is used. Whenever the CPU processes a single piece of microcode, it is referred to as a machine cycle. CMPTR Chapter 2: Computer Hardware 20 10
LO2.4: Storage Systems All storage systems involve two physical parts: storage medium storage device Topics Covered: Hard Drives Optical Discs Flash Memory Network Storage and Online/Cloud Storage Systems Smart Cards Storage Systems for Large Computer Systems CMPTR Chapter 2: Computer Hardware 21 Hard Drives With the exception of computers designed to use only network storage devices, virtually all personal computers come with a hard drive that is used to store most programs and data. Magnetic hard drives contain one or more round pieces of metal (called hard disks or platters) that are coated with a magnetizable substance. CMPTR Chapter 2: Computer Hardware 22 11
Hard Drives CMPTR Chapter 2: Computer Hardware 23 Hard Drives A newer type of hard drive is the solid-state drive (SSD, also called flash memory hard drives), which is a hard drive that uses flash memory technology instead of spinning hard disk platters and magnetic technology. Hard drives can be internal or external. CMPTR Chapter 2: Computer Hardware 24 12
Hard Drives The total time that it takes for a hard drive to read or write data is called the disk access time and requires the following: Seek time -The read/write heads move to the cylinder that contains (or will contain) the desired data. Rotational delay -The hard disks rotate into the proper position so that the read/write heads are located over the part of the cylinder to be used. Data movement time -The data moves, such as reading the data from the hard disk and transfer-ring it to memory, or transfers from memory and is stored on the hard disk. CMPTR Chapter 2: Computer Hardware 25 Hard Drives A disk cache stores copies of data or programs that are located on the hard drive and that might be needed soon in memory chips to avoid having to retrieve the data or programs from the hard drive when they are requested. Hybrid hard drives essentially a combination flash memory/ magnetic hard use a much larger amount of flash memory (up to 1 GB today). CMPTR Chapter 2: Computer Hardware 26 13
Optical Discs Optical discs are thin circular discs made out of polycarbonate substrate essentially a type of very strong plastic that are topped with layers of other materials and coatings used to store data and protect the disc. CMPTR Chapter 2: Computer Hardware 27 Optical Discs Optical discs are designed to be read by optical drives, such as CD, DVD, and BD drives, and the type of optical drive being used must support the type of optical disc being used. CMPTR Chapter 2: Computer Hardware 28 14
Flash Memory Flash memory is a chip-based storage medium that represents data using electrons. CMPTR Chapter 2: Computer Hardware 29 Flash Memory One of the most common types of flash memory media is the flash memory card a small card containing one or more flash memory chips, a controller chip, other electrical components, and metal contacts to connect the card to the device or reader with which it is being used. CMPTR Chapter 2: Computer Hardware 30 15
Flash Memory USB flash drives (sometimes called USB flash memory drives, thumb drives, orjump drives) consist of flash memory media integrated into a self-contained unit that connects to a computer or other device via a standard USB port and is powered via the USB port. CMPTR Chapter 2: Computer Hardware 31 Network Storage and Online/Cloud Storage Systems Remote storage refers to using a storage device that is not connected directly to the user s computer; instead, the device is accessed through a local network or through the Internet. Remote storage devices accessed via the Internet are often referred to as online storage or cloud storage. CMPTR Chapter 2: Computer Hardware 32 16
Network Storage and Online/Cloud Storage Systems Remote storage devices accessed via the Internet are often referred to as online storage or cloud storage. CMPTR Chapter 2: Computer Hardware 33 Smart Cards A smart card is a credit card sized piece of plastic that contains computer circuitry and components typically a processor, memory, and storage. CMPTR Chapter 2: Computer Hardware 34 17
Storage Systems for Large Computer Systems For large computer systems, instead of finding a single hard drive installed within the system unit, you are most likely to find a storage server. Most storage servers are based on magnetic hard disks, although magnetic tape storage systems are also possible. CMPTR Chapter 2: Computer Hardware 35 LO2.5: Input Devices An input deviceis anypiece of equipment that is used to enter data into the computer. Topics Covered: Keyboards Pointing Devices Touch Devices Scanners and Readers Audio Input CMPTR Chapter 2: Computer Hardware 36 18
Keyboards Most computers today are designed to be used with a keyboard a device containing keys used to enter characters on the screen. CMPTR Chapter 2: Computer Hardware 37 Pointing Devices Pointing devices are used to select and manipulate objects, to input certain types of data, such as handwritten data, and to issue commands to the computer. The mouse is the most common pointing device for a desktop computer. CMPTR Chapter 2: Computer Hardware 38 19
Pointing Devices CMPTR Chapter 2: Computer Hardware 39 Touch Devices Touch screens allow the user to touch the screen with his or her finger to select commands or otherwise provide input to the computer associated with the touch screen. A touch pad is a rectangular pad across which a fingertip or thumb slides to move the on-screen pointer; tapping the touch pad typically performs clicks and other mouse actions. CMPTR Chapter 2: Computer Hardware 40 20
Scanners and Readers A scannercaptures an image of an object usually a flat object, such as a printed document, photograph, or drawing in digital form, and then transfers that data to a computer. The quality of scanned images is indicated by optical resolution, usually measured in the number of dots per inch (dpi). CMPTR Chapter 2: Computer Hardware 41 Scanners and Readers A barcode is an optical code that represents data with bars of varying widths or heights. UPC ISBN CMPTR Chapter 2: Computer Hardware 42 21
Scanners and Readers Radio frequency identification (RFID) is a technology that can store, read, and transmit data located in RFID tags. RFID tags contain tiny chips and radio antennas; they can be attached to objects, such as products, price tags, shipping labels, ID cards, assets, and more. The data in RFID tags is read by RFID readers. CMPTR Chapter 2: Computer Hardware 43 Scanners and Readers Other types of readers include: Optical mark reader (OMR): inputs data from special forms to score or tally the data on those forms. Biometric reader: inputs biometric data, such as an individual s fingerprint or voice. CMPTR Chapter 2: Computer Hardware 44 22
Audio Input Audio input is the process of entering audio data into the computer. Speech recognition systems enable the computer to recognize voice input as spoken words and require appropriate software. Music input systems are used to create an original music composition or arrangement, or to create a custom music CD. CMPTR Chapter 2: Computer Hardware 45 LO2.6: Output Devices An output deviceaccepts processed data from the computer and presents the results to the user. Topics Covered: Display Devices Data and Multimedia Projectors Printers Audio Output CMPTR Chapter 2: Computer Hardware 46 23
Display Devices The most common form of output device is a display device. Presents output visually on some sort of screen. CMPTR Chapter 2: Computer Hardware 47 Display Devices Most computers today (as well as most television sets) use the thinner and lighter flat-panel displays. Display devices that use electrically charged chemicals or gases to display images. Flat-panel technologies include: Liquid crystal display (LCD) Light emitting diode (LED) Organic light emitting diode (OLED) Interferometric modulator (IMOD) display Plasma display 3D Display CMPTR Chapter 2: Computer Hardware 48 24
Data and Multimedia Projectors A data projector is used to display output from a computer to a wall or projection screen. Freestanding units Permanently mounted onto ceiling ipod dock Integrated projector 3D/Hologram projector CMPTR Chapter 2: Computer Hardware 49 Printers Instead of the temporary, everchanging soft copy output that a monitor produces, printersproduce hard copy; that is, a permanent copy of output on paper. CMPTR Chapter 2: Computer Hardware 50 25
Audio Output Audio output includes voice, music, and other audible sounds. Portable computers and mobile devices typically have speakers integrated into the device; mobile devices can also be connected to a stereo system or other consumer device that contains an ipod/mp3 dock and integrated speakers designed to be used to play music stored on a portable digital media player. CMPTR Chapter 2: Computer Hardware 51 26