1. Chapter Five Maintaining a Computer Part II: Preventing Damage to Equipment and Preventing Data Loss

2. © 2006-2011 Wiley, Inc. All Rights Reserved. Strata Objectives Covered 2.3 (2.3 FC0-U21 U.K.) Demonstrate the ability to minimize risks –Data loss –Loss of service –Damage to equipment 5.3 (3.2 FC0-U21 U.K.) Identify preventative maintenance products, procedures, and how to use them –Surge suppressors –Use of ESD equipment (U.S. only) –Wire placement and safety (U. S. only) 2

3. © 2006-2011 Wiley, Inc. All Rights Reserved. Strata Objectives Covered 3.1 FC0-U21 U.K. (no U.S. equivalent) Recognize safety hazards and identify corresponding guidelines –Hazards –Fire –Flood –Electrical surges –Extreme storms –Environmental hazards –Guidelines –Use of ESD equipment –Use of tools and equipment –Electricity and safety –Wire placement and safety 3

4. © 2006-2011 Wiley, Inc. All Rights Reserved. How Computers Get Damaged Static electricity ruins circuitry via overvoltage Water/liquids cause short circuits Physical trauma breaks mechanical parts and cracks screens and cases 4

5. © 2006-2011 Wiley, Inc. All Rights Reserved. Electrostatic Discharge (ESD) Commonly known as static electricity Most common reason for ruined PC parts Occurs when two items of unequal voltage potential touch When current builds up in your body and you touch a part, that current zaps the part 5

6. © 2006-2011 Wiley, Inc. All Rights Reserved. Electrostatic Discharge (ESD) ESD is low-current, high-voltage Electronic equipment is extremely sensitive to damage by high voltage You can destroy or weaken a circuit board with ESD without knowing it 6

7. © 2006-2011 Wiley, Inc. All Rights Reserved. Electrostatic Discharge (ESD) Any exposed circuit boards are targets for ESD damage –Motherboard –Expansion boards –Memory 7

8. © 2006-2011 Wiley, Inc. All Rights Reserved. Ways to Avoid ESD Synthetic clothing generates more ESD than natural fibers like cotton or wool Avoid working in stocking feet—wear rubber-soled shoes Keep the humidity in the workroom between 50 and 80 percent Work on a tile or linoleum floor, not on carpet 8

9. © 2006-2011 Wiley, Inc. All Rights Reserved. Ways to Avoid ESD Grounding can eliminate ESD risk To ground yourself, wear an antistatic wrist strap as you work Attach the other end to a grounding pin in an electrical outlet If no grounding source is available, attach the clip to the PC’s metal frame 9

10. © 2006-2011 Wiley, Inc. All Rights Reserved. Ways to Avoid ESD If no wrist strap is available, touch the metal frame or power supply frequently as you work This doesn’t ground you but it equalizes the electrical potential between you and the PC 10

11. © 2006-2011 Wiley, Inc. All Rights Reserved. Ways to Avoid ESD New boards come in antistatic plastic bags –Keep parts in the bags until you are ready to install them –Protection is only in the bag, not on top of it Antistatic spray can minimize static buildup in your work environment –Spray on carpet and clothing 11

12. © 2006-2011 Wiley, Inc. All Rights Reserved. Electromagnetic Interference (EMI) Electricity passing nearby generates a magnetic field that interferes with the operation of a cable or device Also called crosstalk Occurs only when the devices are on and sending data via cable Usually causes no permanent damage, but can cause data loss 12

13. © 2006-2011 Wiley, Inc. All Rights Reserved. Electromagnetic Interference (EMI) Can come from: –Unshielded cables –High-voltage power lines –Fluorescent lights –Radio transmitters Can cause problems with data corruption, such as a printer printing garbage characters interspersed with normal characters 13

14. © 2006-2011 Wiley, Inc. All Rights Reserved. Electromagnetic Interference (EMI) To avoid EMI: –Do not run any cables close to each other if possible –Use shorter cables –Use shielded cables if EMI is a problem 14

15. © 2006-2011 Wiley, Inc. All Rights Reserved. Surge Suppression and Power Conditioning Power surge: too much voltage Power spike: an extreme power surge Power sag: too little voltage, also called a brownout 15

16. © 2006-2011 Wiley, Inc. All Rights Reserved. Surge Suppressor An extension cord that contains surge protection 16

17. © 2006-2011 Wiley, Inc. All Rights Reserved. Surge Suppressor Metal oxide variable resistor (varistor) absorbs any excess power Varistor works by depleting its own ability to resist Over time, a surge suppressor loses its effectiveness 17

18. © 2006-2011 Wiley, Inc. All Rights Reserved. Power Conditioning Power conditioning corrects power sags by boosting the voltage when it is insufficient Power conditioning is often combined with the functions of an uninterruptible power supply (UPS) 18

19. © 2006-2011 Wiley, Inc. All Rights Reserved. Power Conditioning UPS is a combination of a surge suppressor and a battery backup 19

20. © 2006-2011 Wiley, Inc. All Rights Reserved. UPS Two types of UPS devices: –Online UPS: runs off the battery all the time More expensive Slightly more reliable because no quick change-over to battery power is required –Standby UPS: runs off the battery only when regular power is off or insufficient Less expensive If changeover doesn’t happen fast enough, devices may lose power momentarily and reboot 20

21. © 2006-2011 Wiley, Inc. All Rights Reserved. Liquids Keep water away from electronics Do not set beverages near the computer Do not set cold items on an air vent that may drip water from condensation into the PC Do not spray liquid cleaning products directly onto the PC, especially near vents 21

22. © 2006-2011 Wiley, Inc. All Rights Reserved. Temperature PCs become hot as they operate –Cooling fans and heat sinks help –Having a clean PC with clear air pathways helps PCs prefer a cooler environment than humans do, but not below freezing Avoid storing or using a PC in extreme heat or cold conditions 22

23. © 2006-2011 Wiley, Inc. All Rights Reserved. Physical Trauma Causes parts to break or come loose –Circuit boards pop out of slots –Cables become loosened –Cases and screens crack On magnetic hard disks, read/write heads crash against disk surface, causing data read/write errors 23

24. © 2006-2011 Wiley, Inc. All Rights Reserved. Physical Trauma Store portable computers in well- padded cases for transport Place desktop computers on solid, stable surfaces only Keep cords well away from walking paths 24

25. © 2006-2011 Wiley, Inc. All Rights Reserved. Magnets Magnets can create an electrical charge in a component –Physical harm due to overvoltage –Electromagnetic interference when operating Use only non-magnetic screwdrivers and other tools inside a PC 25

26. © 2006-2011 Wiley, Inc. All Rights Reserved. Battery Conservation Carry an extra battery for notebook computer if possible Adjust power settings in the OS to extend the battery life Turn off your wireless network adapter unless you are actively using it Set the screen display to be less bright 26

27. © 2006-2011 Wiley, Inc. All Rights Reserved. Battery Conservation Set the screen saver to blank the screen after a certain amount of idle time Mute the sound Minimize the use of external devices that draw power from the notebook Remove any unused ExpressCards or other peripheral cards 27

28. © 2006-2011 Wiley, Inc. All Rights Reserved. Backup Solutions RAID systems Local backup applications Online backup services Network backup Manual file copying System imaging 28

29. © 2006-2011 Wiley, Inc. All Rights Reserved. Making a Backup Plan How often do you plan to back up? How large are the files? What backup software is available? What files should be backed up: –Full: Backs up everything –Differential: Backs up what’s changed since the last full backup –Incremental: Backs up what’s changed since the last backup of any type 29