CompTIA A+ Complete Study Guide phần 8 pot

616 Chapter 12  Working with Personal Computer Components Memory Usage The CPU is capable of differentiating between system memory, which is what you refer to when you say that your computer has 512MB or 1GB of RAM, and I/O memory, which is a resource allocated to an expansion card and other components external to the CPU. A single pin on the CPU, called the I/O_MEM line, allows the CPU to specify which group of memory it is referring to for read or write operations. In addition, the two blocks of memory can over- lap in value, due to the fact that the CPU refers to one or the other per operation, never both, eliminating the possibility of confusion. Memory Addresses Many components use blocks of system memory as part of their normal functioning, often finding their data elbow to elbow with application data and code. For example, network inter- face cards often buffer incoming data in a block of memory until it can be processed. Doing so prevents the card from being overloaded if a burst of data is received from the network. When the device driver loads, it lets the CPU know which block of system memory should be set aside for the exclusive use of the component. This prevents other devices and software from overwriting the information stored there. Certain system components, such as the system board and the PCI bus, also need a memory address. Memory addresses are usually expressed in a hexadecimal range with eight digits, such as 00F0000–000FFFFF. When the CPU indi- cates MEM with the I/O_MEM line, it is referring to a memory address. Direct Memory Access Direct memory access (DMA) allows a device to bypass the CPU and place data directly into RAM. To accomplish this, the device must have a DMA channel devoted to its use. All DMA transfers use a special area of memory set aside to receive data from the expansion card (or CPU, if the transfer is going the other direction) known as a buffer. The basic archi- tecture of the PC DMA buffers is limited in size and memory location. No DMA channel can be used by more than one device. If you accidentally choose a DMA channel that another card is using, the usual symptom is that no DMA transfers occur and the device is unavailable. Certain DMA channels are assigned to standard AT devices. DMA is no longer as pop- ular as it once was, because of advances in hardware technology, but it is still used by floppy drives and some keyboards and sound cards. The floppy-disk controller typically uses DMA channel 2. A modern system is not likely to run short on DMA channels because so few devices use them anymore. I/O Addresses I/O (input/output) addresses, also known as port addresses, are a specific area of memory that a component uses to communicate with the system. When the CPU indicates I/O with the I/O_ MEM line, it is referring to an I/O address. Although I/O addresses sound quite a bit like mem- ory addresses, the major difference is that memory addresses are used to store information that 4831x.book Page 616 Tuesday, September 12, 2006 11:59 AM Using Tools and Diagnostic Procedures for Personal Computer Components 617 will be used by the device itself. I/O addresses are used to store information that will be used by the system or to represent instructions for the device from the CPU. For instance, the I/O address range 01F0–01F7 for the primary IDE controller acts as a set of instructions allowing the CPU to control the activities of the IDE controller. An I/O address is typically expressed using only the last four digits of the full address, such as 03E8, because the first four digits are always zeros. All I/O addresses fall within the first 640KB, starting at 0. Although the I/O addresses for a component are technically a range, such as 03E8–03EF for COM3, you more often refer to the base I/O address, just 03E8 in this case. The exam asks about a few I/O addresses; Table 12.3 lists a few of the hexadecimal addresses that you should know. Determining Available Resources The best way to determine the PC’s available resources is by using hardware-configuration- discovery utilities. These software programs talk to the PC’s BIOS as well as the various pieces of hardware in the computer and display which IRQ, DMA, I/O addresses, and memory addresses are being used. Most operating systems include some way of determining this infor- mation, including Device Manager in Windows 2000/XP. Exercise 12.9 guides you through investigating your system resources. TABLE 12.3 I/O Addresses Port I/O Address COM1 03F8–03FF COM2 02F8–02FF COM3 03E8–03EF COM4 02E8–02EF LPT1 0378–037F LPT2 0278–027F Primary IDE 01F0–01F7 Secondary IDE 0170–0177 4831x.book Page 617 Tuesday, September 12, 2006 11:59 AM 618 Chapter 12  Working with Personal Computer Components EXERCISE 12.9 Displaying System Resources To display the system resources currently in use, follow these steps: 1. Right-click My Computer and choose Properties to bring up the System Properties dialog. 2. Click the Hardware tab, and then click the Device Manager button. 3. To display a device’s resources, open the category by clicking the plus sign next to it and double-clicking the device name. Then, look in the Resources tab for that device. 4. In order to see the specifics about how your system allocates a certain type of resource, click the View menu in Device Manager and select Resources By Type. Resources By Con- nection works as well, but some categories are less intuitive. 5. Notice that the four categories correspond to the four resources presented in this section— DMA, I/O address, IRQ, and memory address. Investigate each of the four categories by clicking on the plus sign in front of them. For example, expanding the Interrupt Request cat- egory shows you all components that have IRQs assigned to them in order of IRQ number. 4831x.book Page 618 Tuesday, September 12, 2006 11:59 AM Using Tools and Diagnostic Procedures for Personal Computer Components 619 Manually Specifying a Resource Assignment In the Windows’ Device Manager, you can manually specify the resources for a device to solve a problem with a resource conflict—that is, a situation in which two or more devices lay claim to the same resource. A resource conflict usually appears as a yellow exclamation point next to a device’s name in Device Manager. Double-clicking the device opens its Properties box, and on the Resources tab you will find an explanation of the problem in the Conflicting Device list. To change a device’s resource assignments, clear the Use Automatic Settings check box and select a different configuration from the Settings Based On drop-down list. (See Figure 12.2.) If none of the alternate configurations resolves the conflict, you can double-click a specific resource on the Resource Type list and enter a manual setting for it. Most modern computers use a power management and configuration method called ACPI (advanced configuration and power interface), which helps prevent resource conflicts but which also limits the amount of tinkering you can do with manual resource assignments. If you get a message that a particular resource cannot be changed, or if the Use Automatic Settings check box is unavailable, it is probably because of ACPI. If the device is not Plug and Play compatible, it may have jumpers for hard-setting the resources assigned to it. If that’s the case, Windows will not be able to change these assign- ments; it will use the assignments the device requires, based on its jumper settings. You can also get this same information through the System Information utility. To run it, choose Start  (All) Programs  Accessories  System Tools  System Information. Click the plus sign next to Hardware Resources, and then click one of the categories in the left pane to see the information in the right pane. EXERCISE 12.9 (continued) 4831x.book Page 619 Tuesday, September 12, 2006 11:59 AM 620 Chapter 12  Working with Personal Computer Components FIGURE 12.2 Manually changing a resource assignment Diagnostic Resources When you are stumped by a computer problem, where do you turn? Try manuals, the Web, and training. User/Installation Manuals Consult the manuals that came with the hardware and software. Internet/Web Resources Consult the websites of the companies that make the hardware and software. Updates and patches are often available for download, or the websites may offer knowledge bases of troubleshooting information and downloadable manuals as well as live forums for those with similar problems to discuss their issues. Training Materials If you have taken a class pertaining to the hardware or software, consult the materials you received for that class. Diagnostic Tools and Utilities A big part of being a successful technician is knowing what tools are appropriate to correct which problems. The following diagnostic tools and utilities are ones you should be comfort- able with: Task Manager Lets you shut down nonresponsive applications selectively in all Windows ver- sions. In Windows 2000/XP, it does much more, allowing you to see which processes and appli- cations are using the most system resources. To display Task Manager, press Ctrl+Alt+Delete. Task Manager appears immediately in Windows 9x; in Windows 2000/XP, you must click the Task Manager button to display it after pressing Ctrl+Alt+Delete. Use Task Manager when- ever the system seems bogged down by an unresponsive application. 4831x.book Page 620 Tuesday, September 12, 2006 11:59 AM Using Tools and Diagnostic Procedures for Personal Computer Components 621 Dr. Watson This tool enables detailed logging of errors. Use it whenever you think an error is likely to occur (for example, when you’re trying to reproduce an error). Event Viewer This tool enables you to see what’s been going on behind the scenes in Win- dows NT/2000/XP. Use Event Viewer when you want to gather information about a system or hardware problem. Device Manager As already mentioned, Device Manager shows you what hardware is installed and lets you check its status. Use this when a device is not functioning and you are trying to figure out why. WinMSD Another name for System Information, the same utility you can select from the System Tools menu. (Running it at the Run command with WINMSD is an alternative.) WinMSD provides comprehensive information about the system’s resource usage, hardware, and software environments. Use it when you need to gather information about the system. Recovery CD Some computers that come with Windows preinstalled do not come with a full version of Microsoft Windows; instead they come with a Recovery CD that can be used to return the PC to its original factory configuration. The important thing to know about these Recovery CDs is that they wipe out all user data and applications. Use one only when you can- not restore system functionality in any less-drastic way. CHKDSK One utility for checking the integrity of magnetic media that has been around since the dawn of the PC operating system, DOS that is, is CHKDSK. CHKDSK is run from a command prompt and scrubs the disk to varying degrees for surface-level and filesystem imperfections. The imperfections can even be corrected in many cases, if you request that they be. Table 12.4 lists the primary switches for CHKDSK and their descriptions. Switches can be specified in series and two of the switches imply the third switch without your explicitly specifying it. Hardware Tools In addition to the software tools included with the operating system, there are a number of hardware tools you should be familiar with as well. The exam objectives specifically mention familiarity with these tools: TABLE 12.4 Common CHKDSK Software Switches Switch Description /F Attempts to fix any errors it finds. /R Searches for bad sectors and recovers readable information to good sectors else- where on the disk, if the bad sectors are not unreadable. The /F switch is auto- matically enabled with this switch so that errors found can be fixed. /X Forces the volume to dismount, if necessary, before CHKDSK runs. Any handles to the volume are invalidated and clients lose access to the server. The /F switch is automatically enabled with this switch so that errors found can be fixed. 4831x.book Page 621 Tuesday, September 12, 2006 11:59 AM 622 Chapter 12  Working with Personal Computer Components Multi-meter A multi-meter (also written as multimeter) combines a number of tools into one. While there can be slight deviations, they always include a voltmeter, ohmmeter, and ammeter (and are sometimes called VOMs, as an acronym for volt-ohmmeter). Antistatic Pad and Wrist Strap The need for an antistatic strap was discussed in the first objective of this chapter. A properly grounded strap can save you from suffering a nasty jolt. An antistatic pad works similarly and can not only protect you but also can protect sensitive equipment from static damage as well. Another option is antistatic spray. Usually applied as a mist to carpets, chairs, and so on, this reduces the amount of static electricity present and can save computers and components. Specialty Hardware/Tools While specialty tools can include anything needed for a specific purpose, there are a few things you should always have: a parts grabber for picking up pieces that have fallen or are hard to hold on to, a chip extractor, and wire cutters/strippers/crimpers. These tools can be used to solve a number of problems. Loop-Back Plugs Also called wrap plugs, loop-back plugs take the signal going out and essentially echo it back. This allows you to test parallel and serial ports to make certain they are working correctly. Cleaning Products A good hand vacuum is a necessity. You need to be able to vacuum up dust, debris, and even toner on occasion. Because of this, you want a vacuum that is capable of collecting small particles and will not pass them through the bag and back in to the air. Spend the money on a good vacuum and you will be glad you did. Vacuums designed to be used safely inside the com- puter case are available, and only vacuums built for this purpose should be used. An assortment of other cleaning supplies should also be available. This would include cleaning pads for monitors, contact cleaner, compressed air, tape-head and optical lens cleaners, and CD cleaning supplies. Performing Preventative Maintenance for Personal Computer Components If the best defense is a good offense, then preventative maintenance truly is the best defense. This section, although short, gets right to the point on maintaining some of the most common components. Chapter 2 included a great deal of information on preventative maintenance products and procedures. Rather than repeating the information from objec- tive 1.4 of the Essentials exam verbatim, it is expected that you read that infor- mation, and the content here builds upon that. 4831x.book Page 622 Tuesday, September 12, 2006 11:59 AM Exam Essentials 623 Display Devices Keep them clean to prevent them from overheating, and make sure they have adequate ventilation. Depending upon the type and size of monitor, it may generate a considerable amount of heat. This heat needs to be vented away to keep the device working properly, and you must make sure the heat from the monitor does not go into other devices that are also heat sensitive. Power Devices In the days of old, it was common procedure to turn the power off on a com- puter and solve your problems with a reboot. Today, so many files on a system are open at any given time that doing so could cause irreparable harm to data. Just as you would no longer “pull the plug,” you want to make sure this does not happen outside of your control. There- fore, you should consider adding surge protectors, power strips, UPSs, and other devices to the PC. Most UPSs now include software that can trigger the PC to safely shut down if the power stays off for a long enough time that the battery in the UPS begins to get low. Input Devices If you are working in an environment with a large amount of contaminants (a factory floor, for example), you should consider covering the input devices. Many supply houses carry disposable covers that can be placed over keyboards and other devices to keep out dirt, liquid, grime, and other impurities in these environments. Storage Devices Keep the hard drives defragmented as much as possible (use DEFRAG) to keep them working optimally. Monitor them for adequate storage space, and replace or add to them as needed. Thermally Sensitive Devices Motherboards, CPUs, adapter cards, and almost everything else in the PC will react negatively to high temperatures. Make sure there is adequate ventila- tion for your PCs and that you keep them clean to let the heat escape. As with so many other topics on the exam, common sense should be your guide when answering questions about preventative maintenance and computer components. Summary In this chapter, you learned how to remove, install, and configure computer components. Specifically, you explored installing and exchanging motherboards, CPUs, memory, adapter cards, storage devices, power supplies, display devices, input devices, and cooling systems. You also learned about troubleshooting and preventative maintenance techniques that every specialized technician should know. Exam Essentials Know how to remove, install, and configure motherboards. Know how to choose the cor- rect motherboard for the chassis you have. Know how to choose the correct mounting hard- ware to avoid shorting out electrical components. Know the various connectors and headers associated with today’s motherboards. Be aware that there are various formats of BIOS rou- tines and methods to access them. 4831x.book Page 623 Tuesday, September 12, 2006 11:59 AM 624 Chapter 12  Working with Personal Computer Components Know how to remove, install, and configure CPUs. Know how to choose the right CPU for the motherboard you have. Know how to remove and install a CPU in a ZIF socket. Know how to remove, install, and configure memory. Know the difference between vari- ous memory form factors, especially SDRAM and DDR, so you know how to choose the cor- rect memory for your motherboard. Be aware of the fastening mechanisms that modern memory modules employ, how they affect module installation, and how to release them dur- ing module removal. Know how to remove, install, and configure adapter cards. Be aware that adapter cards must match available expansion slots. Know how to remove and install them and how to secure them into the computer chassis. Know how to remove, install, and configure storage devices. Know the difference between the data and power connectors used on storage devices. Be aware of the master/slave relationship used with ATA devices and know the strategy for setting them. Know what it means to partition and format a hard drive. Be aware of the physical differences in storage-device form factors. Know how to remove, install, and configure power supplies. Know the difference between the modern motherboard power headers, and be aware of when an adapter might be required. Know the two most common device connectors coming from the power supply. Be familiar with how to fasten power supplies to the chassis, as well as how to unfasten them. Know how to remove, install, and configure display devices. Know the display device choices on the market today. Know the general configuration aspects of each type of device. Know the specific adjustments most commonly available. Know how to remove, install, and configure input devices. Be aware of what constitutes an input device. Know how to connect an input device to a computer and how to disconnect one. Familiarize yourself with common mouse configuration. Know how to remove, install, and configure cooling systems. Know that cooling systems range from passive heat sinks to liquid cooling systems. Know the specifics on removing and installing the more common devices and the general concept of dealing with the more complex devices. Know the default IRQs for COM ports and common devices. Know the default IRQs for COM ports and common devices such as modems, sound cards, disk drives, and so on. Be familiar with Device Manager. Device Manager can display information about the com- puter’s memory, I/O ports, IRQs being used, and many other PC resources. Understand how manual resource assignments are set. Manual resource assignments for Plug and Play devices are set on the Resources tab of the device’s Properties dialog box. For a non-PnP device, resource assignments are controlled by jumpers on the device itself. Know the hardware tools mentioned. Be able to name the hardware tools and their purpose, as discussed in this section. Be aware of the need to keep systems well ventilated. Heat can be a negative force to almost any PC component, and ventilation can help ensure there is not excessive heat buildup. 4831x.book Page 624 Tuesday, September 12, 2006 11:59 AM Review Questions 625 Review Questions 1. Which statement is true regarding upgrading a computer system? A. When upgrading RAM, you must also upgrade the CPU. B. When upgrading RAM, you must perform a forklift upgrade on the entire system. C. When upgrading RAM, it is possible that you can upgrade RAM only. D. RAM is the only upgrade you can perform on modern computer systems. 2. Which two of the following are today’s best choices for video adapter technology? A. ISA B. PCI C. PCIe D. AGP 3. Which of the following is not a selection criterion for RAM? A. Physical size B. Solid state C. Speed D. Capacity 4. While installing a CPU, you apply gentle pressure to the surface of the CPU, but it will not seat. When you examine the pins of the CPU to see if they are straight, you find that a number of them are bent. Why are the bent pins not the original problem? A. The socket has a ZIF mechanism that must be released before inserting the CPU. B. The holes in the socket are large enough to accept pins bent up to 45 degrees from perpendicular. C. The bent metal protrusions around the edge of a chip are not pins. They are non-electronic tensioners to make sure the CPU maintains a tight connection. D. CPUs don’t have pins. What you thought were pins were metallic designs in the likeness of the manufacturer’s logo. 5. Which of the following statements regarding motherboard replacement is not true? A. As you remove any electronic components, including the motherboard and its adapters, you should place them in antistatic containers. B. Existing power supply connectors might not fit the new motherboard. C. Existing memory modules might not fit the new motherboard. D. When removing the motherboard, it is recommended that you not remove the expansion boards, so that you do not subject them to static. 4831x.book Page 625 Tuesday, September 12, 2006 11:59 AM [...]... probation, was fined the equivalent of $87 2, and had his laptop confiscated Several cases like this are pending in U.S courts as well The most common standard for the last several years has been 80 2.11b, which provides wireless speeds up to 11Mbps Newer still is 80 2.11g, which is backward compatible with 80 2.11b and provides data transmission of up to 54Mbps Both 80 2.11b and 80 2.11g operate in the 2.4GHz band,... encoding schemes Another standard you will occasionally run into is 80 2.11a This standard operates at a different frequency (the 5GHz band), uses a different encoding scheme than 80 2.11b and 80 2.11g, and is not compatible with either of them Ethernet Devices Most laptops today come with an internal 80 2.11 adapter Often the laptop will claim to be 80 2.11b/g compatible, meaning it can handle either type of network... connector for the fan and obtain an adapter, if necessary  483 1x.book Page 6 28 Tuesday, September 12, 2006 11:59 AM 6 28 Chapter 12 Working with Personal Computer Components 17 Which system resource allows an expansion card, for instance, to signal the CPU that it requires some of the CPU’s time? A I/O memory B DMA channels C IRQ lines D Memory addresses 18 Which of the following is considered a diagnostic... power Remove unneeded peripherals Plug in external monitor Toggle Fn keys Check LCD cutoff switch 483 1xc13.fm Page 632 Wednesday, September 13, 2006 7:49 PM Verify backlight functionality and pixilation Stylus issues (e.g digitizer problems) Unique laptop keypad issues Antenna wires THE FOLLOWING COMPTIA A+ DEPOT TECHNICIAN EXAM OBJECTIVES ARE COVERED IN THIS CHAPTER: 2.1 Identify the fundamental principles... other GSM uses a variety of bands to transmit The most popular are 900MHz and 180 0MHz, but 400, 450, and 85 0MHz are also used Because of this, one phone cannot work at full capacity on all the GSM networks in the world GSM splits up its channels by time division, in a process called Time Division Multiple Access (TDMA)  483 1xc13.fm Page 640 Wednesday, September 13, 2006 7:49 PM 640 Chapter 13 Laptop... Manager and Control Panel allow you to monitor and alter certain items, but not hardware resources the way Device Manager is designed to do  483 1xc13.fm Page 631 Wednesday, September 13, 2006 7:49 PM Chapter 13 Laptop and Portable Devices THE FOLLOWING COMPTIA A+ IT TECHNICIAN EXAM OBJECTIVES ARE COVERED IN THIS CHAPTER: 2.1 Identify fundamental principles of using laptops and portable devices Identify... line of sight, and generally speaking the two devices need to be pointed at each other to work If you point your remote away from the television, how well does it work? 483 1xc13.fm Page 6 38 Wednesday, September 13, 2006 7:49 PM 6 38 Chapter 13 Laptop and Portable Devices More information on the IrDA standard can be found at the organization’s website: http://www.irda.org Most laptops have a built-in... located Other types of hardware in some laptops require you to release a latch The following photo shows a modular front-load bay, and the right side has a CD-ROM in it  483 1xc13.fm Page 6 48 Wednesday, September 13, 2006 7:49 PM 6 48 Chapter 13 Laptop and Portable Devices EXERCISE 13.1 (continued) 4 Turn the computer over, and you can see the release latch Slide it to the side, and pull on the grip on... is no such thing as complete mode Without any adjustment to the boot process, you boot into normal mode Safe mode and VGA mode are used during troubleshooting various problems that prevent successful booting in normal mode, including graphics issues 14 D Although a geometric shape like the trapezoid, rhombus is not a video configuration setting The other three options are 15 A 1 /8- inch jacks, or minijacks,... installed 13 Which of the following is not a Microsoft boot mode? A Normal mode B Complete mode C Safe mode D VGA mode 14 Which of the following is not a configuration option for computer video? A Pincushion B Contrast C Trapezoid D Rhombus 15 Which of the following is not an example of a standard input device connector? A 1 /8- inch jack B Mini-DIN C D-subminiature D USB 16 When installing a CPU fan and . 12.9 guides you through investigating your system resources. TABLE 12.3 I/O Addresses Port I/O Address COM1 03F8–03FF COM2 02F8–02FF COM3 03E8–03EF COM4 02E8–02EF LPT1 03 78 037F LPT2 02 78 027F Primary. Device Manager is designed to do. 483 1x.book Page 630 Tuesday, September 12, 2006 11:59 AM Chapter 13 Laptop and Portable Devices THE FOLLOWING COMPTIA A+ IT TECHNICIAN EXAM OBJECTIVES. (e.g. digitizer problems)  Unique laptop keypad issues  Antenna wires THE FOLLOWING COMPTIA A+ DEPOT TECHNICIAN EXAM OBJECTIVES ARE COVERED IN THIS CHAPTER:  2.1 Identify the fundamental