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

Chapter Five

Maintaining a ComputerPart II: Preventing Damage to

Equipment and Preventing Data Loss

© 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)

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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

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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

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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

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• 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

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• Any exposed circuit boards are targets for ESD damage– Motherboard– Expansion boards– Memory

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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

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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

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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

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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

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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

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• 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

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• 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

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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

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Surge Suppressor

• An extension cord that contains surge protection

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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

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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)

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Power Conditioning

• UPS is a combination of a surge suppressor and a battery backup

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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

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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

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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

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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

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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

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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

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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

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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

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Backup Solutions

• RAID systems• Local backup applications• Online backup services• Network backup• Manual file copying• System imaging

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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

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Documents

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