A
computer is a fabulous instrument that turns human inputs into electronic
information that it then can store or share/distribute through various output devices. A computer performs (if instructed to do so)
the steps shown in the diagram below, using information that a user provides
(such as a typed sentence):
All
of the equipment (hardware) and the instructions (software) needed to complete
the above steps are described in the next section.
Amazingly,
the information that the user inputs into a computer is processed so that it
becomes a simple code made up of only two digits: zero and one! For all its complexity, a computer is only
able to handle these two choices. This
is because it is based on electrical signals that have only two options (such
as either on or off). But computers
compensate for this very simple code by using it in huge quantities. A single unit of this zero/one code is called
a bit. Grouping 8 bits together makes a
unit of information called a byte. Typing
a single page of typed text on a computer requires a minimum of about 20 kilobytes
(20 KB or 20,000 bytes) of information to be stored. Good quality digital photographs are usually
1 megabyte (1 MB or 1,000,000 bytes) or larger.
So a computer is a very “busy” machine indeed!
1.2.1. Basic Hardware Components
Hardware
is the physical equipment needed for a computer to function properly. The basic hardware parts are briefly described
here. Many computer lab managers will
already have been exposed to computer hardware through other courses, but those
desiring additional information can find it in a variety of texts and online
sources. A desktop computer is used in
the photos, but all of this equipment is also found (in a more compact
arrangement) in a laptop computer.
Case. The computer case
(also called a tower or housing) is the box that encloses many of the parts
shown below. It has attachment points,
slots and screws that allow these parts to be fitted onto the case. The case is also sometimes called the CPU,
since it houses the CPU (central processing unit or processor), but this
designation can lead to confusion.
Please see the description of the processor, below.
Power Supply. The power
supply is used to connect all of the parts of the computer described below to
electrical power. It is usually is found
at the back of the computer case.
Fan. A fan is needed
to disperse the significant amount of heat that is generated by the
electrically powered parts in a computer.
It is important for preventing overheating of the various electronic
components. Some computers will also
have a heat sink (a piece of fluted metal) located near the processor to absorb
heat from the processor.
Motherboard. The
motherboard is a large electronic board that is used to connect the power
supply to various other electronic parts, and to hold these parts in place on
the computer. The computer’s memory (RAM,
described below) and processor are attached to the motherboard. Also found on the motherboard is the BIOS
(Basic Input and Output System) chip that is responsible for some fundamental
operations of the computer, such as linking hardware and software. The motherboard also contains a small battery
(that looks like a watch battery) and the chips that work with it to store the
system time and some other computer settings.
Drives. A
computer’s drives are the devices used for long term storage of
information. The main storage area for a
computer is its internal hard drive (also
called a hard disk). The computer should
also have disk drives for some sort of removable storage media. A floppy
disk drive was very common until recent years, and is still found on many
older desk top computers. It was
replaced by CD-ROM and DVD drives, which have higher storage
capacities. The current standard is a DVD-RW drive, which can both read and
write information using both CD and DVD disks.
The USB ports (described later) on a computer can also be used to
connect other storage devices such as flash
drives and external hard drives.
Cards. This
term is used to describe important tools that allow your computer to connect
and communicate with various input and output devices. The term “card” is used because these items
are relatively flat in order to fit into the slots provided in the computer
case. A computer will probably have a
sound card, a video card, a network card and a modem.
RAM. RAM is the abbreviation
for random access memory. This is the
short term memory that is used to store documents while they are being
processed. The amount of RAM in a
computer is one of the factors that affect the speed of a computer. RAM attaches to the motherboard via some
specific slots. It is important to have
the right type of RAM for a specific computer, as RAM has changed over the
years.
Processor. The
processor is the main “brain” of a computer system. It performs all of the instructions and
calculations that are needed and manages the flow of information through a
computer. It is also called the CPU
(central processing unit), although this term can also be used to describe a
computer case along with all of the hardware found inside it. Another name for the processor is a computer
“chip” although this term can refer to other lesser processors (such as the
BIOS). Processors are continually
evolving and becoming faster and more powerful.
The speed of a processor is measured in megahertz (MHz) or gigahertz
(GHz). An older computer might have a
processor with a speed of 1000 MHz (equivalent to 1 GHz) or lower, but processors
with speeds of over 2 GHz are now common.
One processor company, Intel, made a popular series of processors called
Pentium. Many reconditioned computers
contain Pentium II, Pentium III and Pentium 4 processors, with Pentium 4 being
the fastest of these.
Peripheral hardware.
Peripheral hardware is the name for the computer components that are not
found within the computer case. This
includes input devices such as a mouse,
microphone and keyboard, which
carry information from the computer user to the processor, and output devices
such as a monitor, printer and speakers, which display or transmit
information from the computer back to the user.
1.2.2. Computer Ports
The
peripheral hardware mentioned above must attach to the computer so that it can
transmit information from the user to the computer (or vice versa). There are a variety of ports present on a
computer for these attachments. These
ports have gradually changed over time as computers have changed to become
faster and easier to work with. Ports
also vary with the type of equipment that connects to the ports. A computer lab manager should become familiar
with the most common ports (and their uses), as described below.
Serial Port. This port for use with 9 pin connectors is no
longer commonly used, but is found on many older computers. It was used for printers, mice, modems and a
variety of other digital devices.
Parallel Port. This long and slender port is also no longer
commonly used, but was the most common way of attaching a printer to a computer
until the introduction of USB ports (see below). The most common parallel port has holes for 25
pins, but other models were also manufactured.
VGA. The Video Graphics Array port is found on most
computers today and is used to connect video display devices such as monitors
and projectors. It has three rows of
holes, for a 15 pin connector.
PS/2. Until recently, this type of port was
commonly used to connect keyboards and mice to computers. Most desktop computers have two of these
round ports for six pin connectors, one for the mouse and one for the
keyboard.
USB. The Universal Serial Bus is now the most
common type of port on a computer. It
was developed in the late 1990s as a way to replace the variety of ports
described above. It can be used to
connect mice, keyboards, printers, and external storage devices such as DVD-RW
drives and flash drives. It has gone
through three different models (USB 1.0, USB 2.0 and USB 3.0), with USB 3.0
being the fastest at sending and receiving information. Older USB devices can be used in newer model
USB ports.
TRS. TRS (tip, ring and sleeve) ports are also
known as ports for mini-jacks or audio jacks.
They are commonly used to connect audio devices such as headphones and
microphones to computers.
Ethernet. This port, which looks like a slightly wider
version of a port for a phone jack, is used to network computers via category 5
(CAT5) network cable. Although many
computers now connect wirelessly, this port is still the standard for wired
networked computers. Some computers also
have the narrower port for an actual phone jack. These are used for modem connections over
telephone lines.
1.3.1. Software Types and Categories
As
mentioned in section 2.1, computer software is the term
used for the instructions that have been programmed to allow a computer to
process information. Software comes in
three main categories, described below:
Operating Systems. These are the basic software programs that are
needed to for a computer to work. They
give a computer the basic information needed for it to process and store information. Currently all common operating systems are
also graphical user interfaces (GUIs) which means they use graphics to help the
user to easily input instructions, and open other programs. The most common operating systems (OS) are
the Windows family of operating systems, from Microsoft. A computer lab manager is likely to encounter
Windows 2000, Windows XP, Windows Vista and Windows 7 (the most recent Microsoft
OS) in a computer lab. Other operating
systems are described in the next section.
Utility Software.
This
is a broad category of programs that allow a computer to perform tasks that
aren’t a part of the operating system, but are still practical and useful. For example, a utility might instruct a
computer on how to copy (burn) information to a CD-ROM disk, or it might be an
anti-virus program (see section 3.3).
Productivity Software.
This
is one term used to describe the type of software used to perform standard
office computer tasks. Word processing,
presentation, spreadsheet and database software are all common examples of
productivity programs. The most common
set of productivity programs is Microsoft Office, offered by the Microsoft
Corporation.
1.3.2. Proprietary Software vs. Open Source Software
The
Microsoft operating system and productivity software packages mentioned above
are very common and used around the world in business and education. The Appttttt le Corporation also has very popular
and successful operating systems used for their Macintosh computers. Despite the success of these software
products, they aren’t the best choices for everyone. They are proprietary, which means that their
use and modification are restricted. They
can be quite costly to buy licenses for, and they are not adaptable to meet
local needs. Some users, particularly in
developing countries, illegally use unlicensed (also known as pirate) copies of
this software. This is legally unwise,
and can also keep the user from accessing important software updates.
Users
who cannot afford proprietary software or prefer software that can be locally
modified, can choose to use open source (often called free and open source or
FOSS) software. For most of the standard
computer uses, an open source software option is available. This includes the Linux family of operating
systems (which includes Ubuntu, a common operating system in African countries)
and the OpenOffice.org productivity programs.
The Source Forge website (www.sourceforge.net)
is a good resource for finding and downloading open source programs. While open source software often does not
come with professional support available, there are user groups found on the Internet
who can offer assistance to puzzled users.
This training module does describe how to perform some tasks using the
Ubuntu operating system, but does not provide thorough coverage. Further assistance with Ubuntu is available
through the website: http://help.ubuntu.com.
When
first setting up a computer lab, the steering committee for a computer project
should discuss the benefits of both proprietary and open source software and
make an informed and intentional choice on which way to go. The computer lab manager should then make
sure that he or she is aware of all policies related to software choices.
It
is possible that a computer project will choose to use proprietary software for
some purposes and open source software for others. For example, a project might be able to
obtain used computers that have a Windows operating system legally installed
(such as through a Microsoft Authorized Refurbisher) but these computers do not
include other Microsoft programs. In
this case the organization might choose to continue to run Windows on its
computers, but choose open source options for all utility and productivity
software.
Please Note:
Throughout this module there are assignments that require a learner to
have access to computers and the Internet.
Students who are not already working as computer lab managers may find
performing these assignments to be difficult.
These learners are encouraged to consult with the staff of a local
computer project or Internet café to gain access to equipment and the Internet. It is even possible that short term
internships could be arranged that would be beneficial to both the learner and
the computer project.
1.4.1.
Study
the exterior of a particular computer.
See if you can identify the power supply, the drives, and all of the
ports described in this chapter.
1.4.2.
Find
a broken or disused desktop computer.
Figure out how to open up the case.
Identify all of the hardware components that have been described in this
chapter.
1.4.3.
What
type of software is used on the computer you use most frequently? Identify the operating system, the
productivity software, the Internet browser and the anti-virus software. For each of these also state whether they are
proprietary or open source. If you are
having trouble finding out information about some of your programs, here are
some tips: To find out about your
computer’s operating system, right click on the Computer or My Computer icon
from your desktop or Start menu. Choose
Properties. To find out about a productivity
program, open that program and then find a menu that includes the word “About”. To find the About screen in Microsoft Office
2007, click on the Microsoft Office Button, then click on Options Ã
Resources à About.
1.4.4.
How
much RAM does the computer you use most frequently have? Also how fast is the processor on this
computer? To find this information,
right click on the Computer or My Computer icon from your desktop or Start menu. Choose Properties.
1.4.5.
Have
a discussion with a manager of a local computer lab about computer operating
systems. What operating systems are
being used in that computer lab and why?
What factors went into the decision to choose an operating system?
1.4.6.
Workshop
Activity: In a group, observe the
exterior of computer. How many ports and
hardware devices can your group identify? Ask the instructor for assistance
with any items that cannot be identified.
1.4.7.
Workshop
Activity: In a group, open up the case of a computer. Identify all of the hardware components that
have been described in this chapter.
1.4.8.
Workshop
Activity: Participate in a group discussion or a debate on the advantages and
disadvantages of using open source software.
1.4.9.
Workshop
Activity: Experiment with an operating
system that you are not familiar with.
See if you can figure out how to change the background, open and close
windows, open and close programs, and perform any other computer tasks that you
frequently perform with other operating systems.
Think
of a computer as being like a human body.
We are advised to perform certain tasks to keep our body in good
shape. These maintenance tasks such as
eating well, avoiding some harmful activities and getting exercise keep our
body in good condition. If we don’t
maintain our bodies, we might end up in the hospital with problems that result
from the abuse such as high blood pressure from eating too much salt, obesity
from not exercising or lung problems from smoking. Similarly, if we allow our computers to
intake harmful materials (such as dust) and programs (such as viruses) and we
don’t keep our software in good condition (updated) then the computer may also
end up with significant problems that are then harder to deal with. Proper maintenance of a computer, on the
other hand, can keep it running smoothly for years and years. Some of the different categories of computer
maintenance are described below.
Software
programmers gradually develop updates for their software packages as they
discover problems with the software and design tools to address or fix these
problems. This can be true for any of
the types of software described in section 2.3, but is
typically most common and important for operating systems. It is important for a computer user to find and install software updates in order
to have well performing computers.
Updating software can be done in a variety of ways, described below.
·
Automatic Updates. If a computer is on a reasonably fast Internet
connection, the easiest way to keep it up to date is to allow the programs to
automati cally check for updates and
download and install them as needed.
When setting up a new computer with Microsoft Windows, this is the
choice that the software recommends. It
does not require any action on the part of the user, and results in a computer
system that is current. To turn on
automatic updates for a Windows operating system, find the Systems and
Maintenance options in the Control Panel.
·
Automatic Alerts for
Updates. If a computer is connected to the Internet,
but the connection is slow at some times of the day, another option is to have
the computer automatically check for updates but not download or install them
until the user elects to do so. For
Microsoft Windows computers, if this option is selected, an alert appears in
the computer’s system tray stating that there are updates waiting, and then the
user can wait until the Internet is faster to install these updates.
·
Manual Updating. A computer user can also turn off all
automatic update checking and choose to manually check for updates. For a computer that is rarely connected to
the Internet, this would be a good option as long as the user remembered to
check when connecting to the Internet.
Also some programs do not have automatic update options, and can only be
updated in this manner. A program
usually has a menu item titled “check for updates” that a user can click on
when connected to the Internet.
·
Offline Updating. If a computer is in a location that never has
access to the Internet, a computer lab manager will need to download updates
from a computer that is connected to the Internet and then transfer them (via a
disk or flash drive) to the computer in question to be installed. This option is also useful if a computer lab
has several computers that all need the same update. Instead of having each
computer download the update separately, one computer could download the update
and then it could be shared amongst all of the computers. Offline updates for operating systems can
easily be found through Internet searches.
Updates to download for Windows computers can also be found through www.microsoft.com/downloads.
Viruses,
spyware and other malicious programs can all be referred to together as
malware. Malware prevention is a
significant maintenance task for a computer lab manager. Without vigilance, a computer lab will
quickly become prey to malware. It will
spread from machine to machine causing the computers to slow down, work
improperly or possibly even stop working altogether. The computer lab manager needs to make sure
that all of the computers have anti-virus software installed, and that this software
is set up so that it regularly updates its virus databases and scans the
computers. The tip box here gives more
details on how to do this.
The
computer lab manager also needs to have strict policies in place to prevent
virus infection. Since viruses are
easily spread by the use of flash drives, the policy could prohibit the use of
flash drives, or require them to be
scanned by a staff member before use.
Another policy to consider is the prohibition of downloading, since
unsuspecting users can accidentally download malware. A firewall that blocks dangerous downloads can
also be useful.
There
are some common hardware problems that can be avoided, or at least made less
frequent by taking particular preventive measures with computers. These preventive measures are listed below.
Dust Control. Dust is very harmful for computer
parts. Excess dust can cause mechanical
failures, particularly on computer components with moving parts. Minimizing dust in a computer lab is an important
part of computer maintenance. Computer
lab cleaning advice is discussed further in Module 2. The computers themselves should be regularly
dusted (wiped with a dry cloth or duster) and if the computers are housed in a
particularly dusty area, the use of dust covers (when the computers are turned
off) is advised. In addition, when a
computer case is opened for other repairs, the dust that has built up inside
the case should be blown out. This works
best with forced air. Different
mechanical and electrical tools are available to compress air. These tools are described in section
5.7.1.
Heat Control. Computer parts, in
particular the CPU, produce a large amount of heat while operating. It is important for this heat to dissipate,
so that the computer is not damaged by overheating. Computers do have fans and heat sinks, but
these will only work well if the air flow to the computer is not blocked. This means, for example, that a laptop
computer should not be left running for any length of time on a soft surface
(like a sofa) that conforms around it, and a desktop computer case should not
be used while in an enclosed cabinet. In
addition, it is ideal that the computer lab temperature be kept low. Using air conditioners is a good option,
since the windows can also be kept closed to minimize dust, but many computer
projects cannot afford air conditioners or the associated electricity
costs. Therefore curtains (to reduce the
heat of the sunlight), open windows and fans are often the best alternatives,
although their use requires increased vigilance against dust.
Surge
Protection. In many countries,
the electrical supply does not have a uniform (well controlled) voltage. Voltage is also variable due to surges that
occur, particularly during thunderstorms and when power is returning after an
outage. Voltage surges can be very
damaging to computers and other electrical components, and it is important to
protect against these events. The
simplest form of surge protection is to purchase surge protecting power (adaptor)
strips. These devices contain 4 or 5
outlets that are protected by a fuse that is blown in case of a power
surge. The quality of these power strips
varies, though, and they cannot be guaranteed to be the safest form of surge
protection. A second form of surge
protection is a surge suppressor that is installed where the main power enters
a computer lab. These devices, though
more expensive, are of higher quality and will protect all of the electrical
components plugged in to electrical sockets within the room. A third option to consider is to purchase
uninterrupted power supplies (UPSs) to share between every two computers in a
computer lab (since a UPS includes six to ten electrical sockets). A UPS regulates the voltage sent to the
sockets located on the UPS itself, and also contains a battery that allows for
continued operation of a computer after a power outage. Depending on the UPS model and the amount of
equipment attached to the UPS, the battery might last for an hour or for just a
few minutes, but even just a few minutes allows enough time for the user to
save their work and shut the computer down properly.
Laptop Maintenance
Issues. For computer labs using laptop computers,
there are a couple of additional issues to be aware of that can affect the
lifespan of the computer. Because
laptop computers are moved around from place to place and handled more roughly
than desktop computers, they are more likely to have hardware problems
develop. One problem area, for example,
is in the AC adaptor port. If it is
found in the back of a laptop computer, it is easy for the computer user to
tilt the laptop backwards and unintentionally place pressure on the AC adaptor
as it is forced against the table top.
The AC port (and any other port located on the back of a laptop) can be
easily damaged from this stress. Therefore computer users should be instructed
on the proper technique to use when picking up a laptop computer. A second problem area for laptop computers is that
the screws on the laptop body gradually become loosened as the computer is
moved about. A computer lab manager
should periodically (perhaps twice a year) tighten the screws on all laptop
computers.
Peripheral
hardware will also last longer if it is well maintained. For peripheral hardware such as printers,
projectors and external drives, all of the advice above about heat, dust and
power surge control is still relevant and important. In addition, there are some tips below for
using printers and projectors that will help these pieces of equipment work
efficiently and last a long time.
Proper Use of an LCD
Projector. An LCD projector is
a valuable tool for making presentations and assisting in training courses. However, these projectors are very expensive
to purchase. If a computer project has
had the good fortune of being able to purchase a projector, it is important
that every effort be taken to make sure that the projector is kept in good
repair. Some suggestions are shown here:
·
Store
and carry the projector in a padded case.
This will keep dust out of the projector and cushion it in case of rough
handling.
·
Keep
a designated surge protecting power strip (adaptor strip) with the projector,
and make sure that all projector users know the importance of using the
projector with surge protector.
·
Make
sure that the appropriate procedure for shutting down the projector is used,
and inform all projector users about the procedure. For most projectors, the proper shut down
procedure includes not unplugging the projector until the cooling process is
complete. This is indicated by a status
light changing color, or a fan turning itself off. It is important to allow the projector bulb
to cool completely in order to extend the life of the bulb.
It is particularly
important to note that the projector bulb, which is the most expensive part in
a projector, will wear out and need to be replaced eventually. Projector bulbs can cost half the price of
buying a new projector! A computer
project will need to make a plan for bulb replacement, ideally even keeping a
spare bulb on hand.
Efficient Use of a
Printer. Most computer labs will have at least one
printer for the use of the computer lab manager and selected computer lab
users. Printers are a great resource,
but if not controlled well they can be overused. This puts unnecessary wear on the printer,
and also uses up expensive ink and paper.
It would be wise for a computer lab manager to have in place some
policies about what sort of material can be printed, and when color ink use is
allowed. Users should also be instructed
to preview their work before printing, to avoid printing unnecessary
pages. In addition, many printers have
different printing settings that control the quality of the printouts and thus
the amount of ink used. Inkjet printers,
for example, usually have an option for “draft” or “fast” printing that uses
significantly less ink, but still looks reasonably good. To find this option when printing a document,
select Print from the File menu (or the Office Button in MS
Word 2007). When the print menu opens,
there will be a Properties button
next to the selected printer. Clicking
here will bring up choices such as the print quality and whether the printout
should be in color or black and white.
2.6.1.
Find
and open the anti-virus software on a computer.
Check to see if the virus database is up to date. If it isn’t, update the software and also see
if there is an option to setup the program to automatically look for
updates. Also see if there is an option
that allows you to schedule regular (daily) scans.
2.6.2.
Go
to a local computer lab and ask the computer lab manager about maintenance
tasks. What tasks does he or she do to keep the computers in good condition,
and how often are these tasks performed (daily, weekly, monthly or
yearly)? If the computer lab manger does
not have any maintenance systems in place, instead report your recommendations
for computer maintenance.
2.6.3.
Open
the case of a computer and observe the dust inside. What tools do you have at hand that could be
used to safely remove that dust without damaging the equipment? Experiment with the equipment that is
available to you and report your findings.
2.6.4.
Figure
out how to set up a printer so that the default print settings are black and
white (not color) and “draft” or “fast” printing.
2.6.5.
Workshop
Activity: Observe a demonstration on how
to properly set up and shut down an LCD projector. Make sure that you have an opportunity to practice
these techniques yourself sometime during the workshop.
2.6.6.
Workshop
Activity: Using provided tools, find and
tighten all of the screws on a laptop computer.
2.6.7.
Workshop
Activity: Participate in a role play (and follow up discussion) in which a lab
manager tries to convince a person with a home computer to bring it in to the
lab for updates.
What should be done
before using a new computer? This
depends very much on where the computer came from and what software was already
installed. If a computer project
receives new computers complete with an operating system and all productivity
software, little needs to be done before using the computers. The computer lab manager should check,
however, to make sure the computer is fully set up to meet the needs of the
project. Some items to investigate are
listed here:
·
Does
the computer already have all of the programs that are desired for the
project? This could include, for
example, an Internet browser, productivity (office) software, antivirus
software or perhaps some educational software.
·
Does
the computer already have all of the files that are desired for the
project? For example, an educational
project might want to have an encyclopedia or some educational presentations
loaded on all of the computers.
·
Does
the computer have separate user accounts with passwords? This is a good way to control what access
some users have to particular programs, files or settings. See section 4.5 for
more information. Another option to
consider is installing and using Microsoft SteadyState as a way to control what
part of a computer certain users can access (see Module 2, section 6.2.4 for
more information).
A
partitioned hard drive is one that has two (or more) different sections for
storage of different types of information.
In some cases, one partition is used to store the operating system and
related files, while the other partition is used to store user documents and
settings. This partitioning is valuable
in cases when the hard disk has n failed, but the partition with the operating
system needs to be reformatted due to some sort of localized problem. Then the computer user’s documents and
settings are not lost in the process. This
sort of partitioning is usually done when installing a computer operating
system. Computer lab managers can see
the tip box in the next section for more information on this process.
A
computer lab manager can, however, create a new partition at any time. If a
new computer arrives with an operating system installed but without a separate
partition, the computer lab manager may want to add one or two partitions. A
separate partition can also be used by a computer lab manager that would like
to have two different operating systems on the same hard drive, with one
operating system loaded onto each partition.
The tip box here describes
the process for creating a partition after an operating system has already been
installed.
If
a computer project receives a new computer with no software or with an
unlicensed operating system, the computer lab manager will need to install a
new operating system. The computer lab
manager will need to choose between installing an open source operating system
(such as Ubuntu) or go with a proprietary operating system (such as Microsoft
Windows). While legal copies of the most
current Microsoft operating system (Windows 7 in 2010) are expensive, a
computer project may be able to find less expensive or free copies of older
versions of Windows, through a Community Microsoft Authorized Refurbisher (MAR). Some computer refurbishing centers in
developing countries are MARs. Please
see the website: www.microsoft.com/communitymar.
An
operating system should be installed from a CD-ROM or DVD disk. Before installation, the computer lab manager
needs to set up the computer so that it boots from the CD or DVD drive first. This is the default arrangement for newer
computers, but older computers may boot first from the floppy drive. After installing the new operating system,
the lab manger needs to be sure to change this back again to the standard boot
order. Details on how to change the boot
order and how to install an operating system are shown in the tip
box here.
Knowing
the proper method for installing and uninstalling programs is important for any
computer lab manager. Consider the
situation, for example, when a computer lab manager has been using fee-based
antivirus software, but the free trial subscription has expired. He or she has decided to install free
anti-virus software, rather than pay a subscription fee for the original
software, but needs to know how to uninstall the initial anti-virus software
first. It is possible that if the
original anti-virus software remains, it will cause conflicts with the new
anti-virus software, either preventing it from functioning properly or slowing
down the computer. Another reason it is
useful to know how to uninstall software, is to know how to respond when a computer
lab user has downloaded software that is unnecessary, inappropriate or slowing
down the computer. The steps for
properly uninstalling software are shown in the tip box here.
Installing
software is typically easier than uninstalling.
The Add/Remove programs screen can be used to install software, but most
software will automatically install once you open its installer program. It is
important, however, that a computer lab manager make sure that he or she is
installing software that is beneficial for the computers, compatible with the
current operating system and will not slow down the functioning of the
computers. A good way to find these
programs is through the C-Net website, www.download.com. More details are included in the tip
box here, which uses touch typing practice software as an example.
A
user account is a set of information that is used by a computer’s operating
system to designate the settings that a particular user prefers (such as
desktop background or icon size), control what files and folders a user can
access, and control what changes a user is permitted to make to a
computer. After a new operating system
has been installed on a computer, the user is required to set up an initial user
account. This account is by default an
administrator account, which means that the user of this account has the
ability to access and change all computer settings, and install and uninstall
programs as desired. In most cases, a
computer lab manager will not want all of the other lab users to also have
these privileges and will therefore want to set up more restricted user
accounts for other computer users.
Depending on the type of computer project, the lab manager might want to
set up general accounts for all users of a certain type (such as an account
called “students” or “clients”) or they might want to set up specific password
protected accounts for individual users.
User
accounts can be easily set up by a lab manager who is logged into a computer
using an administrator account. For a
Windows computer the lab manager would select Start à Control
Panel à User Accounts. On a computer running the Ubuntu
operating system the lab manager would go to the main menu and choose System à Administration Ã
Users and Groups. Once there, the lab manager will able to set
up the account and choose the privileges for those users. For Windows computers, the “standard” account
type should be chosen for all users that the lab manger does not want to have
administrative privileges. The lab
manager can also log in to his or her administrative account on a computer to
remove users or change the passwords on user accounts as needed to control
access.
3.6.1.
Is
the computer you usually use partitioned?
Follow the instructions in the “Tips for Partitioning a Hard Drive” tip
box to the point where you can see what partitions are already there and what
their sizes are. If your computer is
already partitioned, what sorts of files or programs are stored on each partition? See if you can find this out by opening My
Computer.
3.6.2.
Following
the steps in “Tips for Uninstalling Software” tip box, find and uninstall a bit
of unnecessary software that you find on your computer. If the computer is not yours, or if you aren’t
sure which software is unnecessary, ask for assistance and permission first.
3.6.3.
Explore
the www.download.com website. Can you tell the difference between sponsored
(paid advertising) links and the programs that are recommended by CNET? Summarize your findings. Also browse through the different categories
of programs. See if you can find some
that would be useful for a computer project in your area.
3.6.4.
Set
up a new user account on a computer and then log into the computer using this
account. How is the appearance different
and how are the privileges different?
3.6.5.
Workshop
Activity: As a group, find a list of installed software on a computer (for
Windows computers this can be done through the Add/Remove Software tool in the
Control Panel). Review the list and
discuss what each software program does.
Determine whether or not any of these programs should be removed from
the computer.
3.6.6.
Workshop
Activity: As a group, install a new
operating system on a test computer.
3.6.7.
Workshop
Activity: As a group, discuss what types of software are needed for a new
computer. Develop a list of software
that would work well in a computer project in your area. If time allows and the software is available,
install all of these programs on the computer used in the previous activity.
This
section of Module 1 is designed to empower the computer lab manager to take
care of minor computer problems. Without
the knowledge here, many lab managers will end up letting computers sit idle
that could be easily put back into service, or paying for expensive repairs
that could have been handled locally.
There will still be times when computers fail and need to be sent out
for repair by an expert, but those times should be few and far between.
Many
of us have had an experience with a computer in which we open a program, and
then find that we are waiting for over a minute for the program to actually
open. Some of us have also had the experience
of turning on a computer and then having to wait several minutes for the
computer to fully start up and load all of the features that we are accustomed
to seeing on the desktop. There can be
several reasons for this sort of slow speed, and many of these reasons are due
to problems that can be easily addressed.
Several possible problems and the strategies for addressing them are
described in the sections below. Please
note that software solutions are discussed before hardware solutions since the
software solutions are usually the right place to start for computers that have
gradually decreased in performance over time.
In some cases, however, such as much older computers with small amounts
of RAM and slow processors, the hardware solutions will be more effective.
4.1.1. Hard Disk Fragmentation
Over
time, all computer hard disks become fragmented. Fragmentation is when files are stored in
different “pieces” in different places on a hard drive, depending on what
storage space was available when the file was last modified. As the amount of free space on a hard drive
decreases, typically the fragmentation increases. Accessing files becomes slower because the
computer has to look around in different places on the hard drive to find the
different pieces of a file. To address this
problem, a hard drive should be defragmented.
Defragmenting can also become a regular maintenance task for heavily
used computers to keep them performing well.
Most computers come with a defragmentation program installed. On a Windows computer it should be found in Start à All Programs Ã
Accessories Ã
System Tools. If no defragmenting program is found there,
some free defragmenting programs are available from www.download.com.
4.1.2. Excess/Unused Files
As
a hard disk becomes full, a computer’s performance is reduced. It takes more time to find and access needed
files, and defragmentation is not as successful due to a lack of free space to
temporarily move files to while they are being rearranged. For best performance, there should be at
least 1 GB of free space on the computer’s hard disk. Therefore, it is wise for a computer user not
to keep files that are no longer needed.
Files that have been stored in a user’s documents folder that are no
longer needed (such as extra photos or older versions of documents) are best
deleted individually by the user. A
computer lab manager should also have a policy and procedure for regularly
deleting old files created by computer lab users on shared computers. In an educational lab, for example, the lab
manager could announce that student files are deleted at the end of every term,
unless the student makes special arrangements to preserve his or her work.
Sometimes
there are other files, such as temporary Internet files, that are stored on a
computer without the user knowing it. To
delete these sorts of files, perform both of the following techniques:
·
Disk Cleanup. In a Windows computer the Disk Cleanup
utility is found in Start Ã
All Programs Ã
Accessories Ã
System Tools. It scans a hard disk for unnecessary
files, and then (with the user’s permission) removes these files.
·
Deleting Browsing
History. When using the Internet, the browser stores
the recent history of the web pages that the user has viewed, in order to make
it easier to find and load these web pages again. The browser also stores other small bits of
information such as data entered into forms and usernames or passwords if a
user has asked a web page to “remember me” (although this is not a good idea
for shared computers). This stored
information can be easily deleted. In
Mozilla Firefox, choose Clear Recent
History from the Tools
menu. In Internet Explorer, choose Delete Browsing History from the Tools menu.
Excess
software, particularly if it is software that loads when the computer is
booting up, can certainly slow performance.
If a user is certain that a particular program is not used and is not
needed for the computer to function properly, then this software can and should
be deleted, as described in section 4.4. It is also possible to stop some software
from automatically starting up when the computer boots. For computers running Windows operating
systems, the System Configuration Utility can be used to perform this task. From the Start
menu choose Run then type in
“MSCONFIG” (for Windows Vista users, find the Run command line from Start à All
Programs à Accessories à Run). From the
window that appears, choose the Startup tab,
and then unselect any programs that do not need to be enabled during computer
start up.
Most
computers come installed with a program that allows a user to scan the hard
disk for faults and even repair them if possible. On many Windows computers there is a program
called Scandisk, found in Start Ã
All Programs Ã
Accessories Ã
System Tools à Scandisk. Another
option is to run a program called Chkdsk, available on all Windows
computers. To run Ch kdsk, go to Start à My Computer and then right click on the
image for the C: drive. Select Properties and then click on the Tools tab. Under Error Checking, click Check Now. The computer may require the check to happen
while restarting the computer and if so will schedule this task to occur.
4.1.5. Malware
Viruses,
worms, spyware and adware are collectively known as malware. These undesirable programs, which are usually
added without a user’s knowledge, can significantly slow down the performance
of a computer. Keeping antivirus
software up to date and running scans on a regular basis are the best ways to
prevent virus infections. This is
discussed further in section 3.3. Occasionally, however, a computer will still
become infected with a virus or other bit of malware that the anti-virus
program did not catch. Some signs of
these infections, other than slow speed, could be strange files popping up in
folders, new small programs that appear (with an .exe file extension) or odd performance
issues. When this occurs, the computer
lab manager can do an Internet search using the names of the strange files or
programs, or a description of other symptoms.
These searches will often result in information about the particular
malware infection and how to remove it.
Another option for computer lab manager is to try scanning the computer
with a second anti-virus program, which might identify the infection that the
other anti-virus software missed.
However, the lab manager needs to be aware of the possibility that the
two anti-virus programs will conflict with each other and themselves cause the
computer to run poorly. If a second
anti-virus program is installed, the computer lab manager should make sure that
it is not also set up to do any sort of automatic scanning.
4.1.6. Overheating
Excessive
heat can cause a significant decrease in computer performance. In order to cool down an overheated computer processor,
the first step to take is to try to cool the environment around the computer. Avo id operating the computer if the case is
in an enclosed space (such as a drawer or cupboard). Also try to cool the room with fans or
air-conditioning. The next step is to
verify that all of the fans in the computer case are functioning properly. Check around the computer vents to see if the
spinning of the fans can be observed or if airflow can be detected. If neither of these steps address the
problem, the computer lab manager could consider installing additional fans or
replacing the existing fans with higher quality ones.
If
none of the measures discussed above have resulted in improved performance,
it’s possible that a computer does not have sufficient RAM to perform the
desired functions. This problem is most
likely if the computer is rather old and has had a newer (and more memory
demanding) operating system installed. For
example, a computer with only 256 MB of RAM would operate slowly with Windows
XP, and would not be able to operate Windows Vista. One option to address this problem is to
install a less demanding operating system.
The lightweight open source operating system Xubuntu, for example, only
requires 192 MB of RAM.
Another
option is to add more RAM to the computer.
Before taking this step, the computer lab manager would need to find out
the answers to the following questions:
·
How
much RAM does the computer already have? (This information is available from
right clicking on My Computer from
the Start menu.)
·
What
kind of RAM does the computer take? And how much RAM can be added to the
computer? The answers to these questions
are going to depend on the number of memory slots available, and the capacity
of the type of RAM that is compatible with the computer. The best way to find the answers to these
questions is via an Internet search using the brand and model of the computer,
“memory” and “upgrade” as search terms, or by visiting the website for an
online RAM sales company (see section 5.7.3). This should result in the necessary
information to make sure that the right kind of memory is purchased (such as
size and type – for example is it SDRAM or DDR2 SDRAM?). It will also be
important to note whether or not the memory needs to be installed in pairs or if
a single strip of RAM will suffice.
·
Does
the computer have enough slots to add in the desired memory? It is possible that a computer will already
have all of the memory slots filled (for example, there are only two slots and
each is already filled with 128 MB RAM strips).
In this case, it would not be possible to upgrade to 512 MB of RAM by
adding a single strip of 256 MB RAM. The
lab manager instead would need to purchase two 256 MB strips of RAM, and take
out both of the 128 MB strips.
The actual
replacement of RAM will be discussed in section 5.7.3 of
this module.
There
are some computer problems that are common enough that is helpful for a
computer lab manager to have some standard steps that he or she can follow in
case this sort of problem occurs. Below are the stepwise guides for addressing
some standard problems.
4.2.1. The Computer Freezes
It is relatively common for a computer to freeze. When a computer “freezes” it might look like
everything on the screen has gone still, or the computer may no longer
responding to the inputs (such as mouse clicks) of the user. It is also possible that a single program
will freeze while the rest of the computer remains functional. These problems
are not something to panic over, since often they are not a sign of a major
hardware problem but instead a sign of a small glitch that can be easily fixed
by restarting a program or the computer.
The tip box here shows some simple steps that the computer lab
manager can follow.
It
can be very frustrating to have a computer that is totally “dead”. It’s not working at all and the user doesn’t
know the cause. This tip
box includes some steps to take to identify and address some common
causes. 
Often
when there is a problem with a computer’s hardware or software, the computer
will show an error message that explains what the problem is. The computer lab manager should make sure
that he or she reads these error messages and takes the information within them
into account. Below are some common
error message categories and steps that can be taken to address the problems.
4.3.1. Out of Memory Errors
Out
of memory error messages can be caused by a variety of problems, including
memory glitches (that will be solved by rebooting), insufficient memory, poor
memory management, not enough hard disk space, faulty memory and software
problems. The user may be running too
many programs at once, and could try closing some of the open programs. If this doesn’t work, the next step to try is
to reboot the computer and see if that fixes the problem. If it does not, the following approaches
could be considered:
1.
Create
more space on the hard drive by deleting unnecessary files and then
defragmenting.
2.
Investigate
any recently added software. Does the
computer system have enough RAM to run this software? Are there any updates or patches for this
software available on the Internet?
3.
Is
some memory management software running?
If so, disable it and see if performance improves.
4.
There
may be a physical problem with the memory or its connection to the motherboard. Try reseating (removing and replacing) the
RAM and if that does not work swapping the RAM (see section
5.7.3) with the RAM from a working computer.
4.3.2. Memory Parity Errors
The
term parity has to do with two items matching in terms of size, type or
operation. A problem with memory parity
could be caused by conflicts between two memory (RAM) strips that are of
different brands or types. The error
could just be a random occurrence, however, so it is best to try to reboot the
computer first. If this does not help,
the following approaches could be attempted:
1. Remove any recently
installed RAM (see section 5.7.3) to see if it is
causing the issue.
2. Try a different
power outlet or power strip, because a poor power supply could also cause this
error.
3.
There
may be a physical problem with the memory or its connection to the
motherboard. Try reseating the RAM and
if that does not work swapping the RAM with the RAM from a working computer.
4. There may be a
problem with the motherboard. Consider
replacing the motherboard.
4.3.3. “The Blue Screen of Death”
“The
Blue Screen of Death” is the colloquial name given to the error code that
occurs with Windows operating systems when a critical error has occurred that
causes the system to shut down to prevent further errors. Its nickname comes from the fact that the
screen turns blue in color, and the computer “dies” or “crashes”, meaning it is
shut down. These errors are often caused
by poorly functioning device drivers, hardware problems (such as with memory,
power supplies or system overheating), or problems with the system
software. Some suggestions for managing
the Blue Screen of Death are shown in the tip box here.
It
is very important that a computer lab manager not “give up” easily when
presented with a computer problem.
Instead the computer lab manager should turn the problem into an
opportunity to gain knowledge about computers.
This includes asking for help and searching for information about the
particular problem, its causes and solutions.
The first step in this process is to see what advice is available on the
computer itself (or another one running the same operating system). With Windows computers, there are “Help and
Support” documents located on the computer, and more available on the Internet. From the Start
menu, click on Help and Support
and then see which categories of help best match the problem.
If
a computer lab manager doesn’t find the needed answers using Help and Support
on the computer, the next step is to find answers on the Internet. In most cases, the computer problems that a
lab manager encounters will not be new or unique. Someone else would have had the same problem
and would have written a description of how they solved the problem. It is important that the computer lab manager
give very specific search terms and try different terms if not successful at
first. For example, if a lab manager is
having problems getting the sound to work on a specific computer, “sound
problems” would not be a specific enough search. The lab manager would be better trying “sound
problem Dell D600” or “sound failure Dell D600”. If the lab manager knows that the problem is
due to the device driver, an even better search would be “sound device driver
problem Dell D600”.
It isn’t always easy to know the source of a computer
problem, but determining whether the problem is with hardware or software will
help give a computer lab manager some direction for action in troubleshooting
and repair. Some general guidelines for
distinguishing between hardware problems and software problems are in the tip
box here, but one general bit of advice is important for all computer
troubleshooters: think about what was
happening just before the problem occurred.
If new software was just installed, it is quite likely that the problem
is caused by that new software. If a
power surge occurred, it is possible that hardware problems were caused by that
power surge.
4.6.1. Using Safe Mode
Safe
Mode is a convenient tool for both troubleshooting and repairing software
problecms. It is a simplified version of
a Windows operating system, which can often be used when a computer is having
problems that prevent its standard Windows operating system from loading. To boot a computer in Safe Mode the user
should turn on the computer and immediately start tapping the F8 key. After a few moments, the Windows Advanced
Options menu will appear. Using the
arrow keys, the user can select Safe Mode and then click Enter to proceed.
Once
a computer has been started in Safe Mode, it is possible to access the
diagnostic tools such as Chkdsk (described in section 5.1.4). Other options at this point include running
virus scans, uninstalling suspicious software, or using System Restore (see section 5.6.4).
If
a computer user has identified that there is a problem with a particular piece
of software, before uninstalling that software it is wise to see if the software
producers have identified and fixed any problems with that software. In many cases this can be done easily by selecting
the “Check for Updates” command in the software, often found in the Help menu. Updates are groups of software patches (small
fixes to the software’s program) that address problems that were found after
the software was released, or provide improvements to the software. If there are any updates available, these
should be downloaded and installed. In
many cases the computer (or at least the particular software program being
updated) will need to be restarted after installation.
If a particular piece of software does
not have a “Check for Updates” option, the user will need to go to the website
for that software and search there for updates.
This can also be used to search for individual software patches to
address the particular problem that the user has found. It is also possible to do general web
searches on a particular software problem and find patches that have been produced
by individuals or organizations other than those that produced the
software. This can result in good fixes,
but can also introduce other problems into a computer system (such as other
unforeseen software conflicts or malware).
A computer lab manager should proceed very cautiously down this path, if
at all.
4.6.3. Reinstalling Software
If
updates and patches haven’t fixed the problem with a particular piece of
software, reinstalling that software is a good step to try next. This will solve problems caused by the
corruption of software (damage to the programs) that can be caused by
malware. It’s important to properly
uninstall all software before reinstalling it.
More information on uninstalling and reinstalling software is found in section 4.4 of this module.
Reinstalling an operating system is also an option (see section
4.3), but the computer lab manager should make sure that all computer data
has been backed up before taking this action.
System
Restore is a utility program that is found with most versions of the Microsoft
Windows operating system. It
periodically (when major software changes are made or at scheduled times) takes
images of the computer’s operating system and other software. These images, called restore points, are
saved so that the user can “reset” the computer system to that restore point
and thus avoid problems that were caused by later changes. If a computer is reset to an earlier restore
point, however, any software (whether it was problematic or not) that was
installed after the restore point will be uninstalled. To access the System Restore utility on a
Windows computer, go to Start Ã
All Programs Ã
Accessories Ã
System Tools Ã
System Restore.
4.6.5. Booting from a Different Device
During
typical use a computer boots (starts) from information and instructions that
are in its internal hard drive. A
computer can also be booted, however, from other devices such as floppy disks,
CD/DVD disks, flash drives or external hard drives. Booting from these devices is the only option
if the software on the hard drive has been corrupted to the point that it will
not start the computer. The standard
boot order for a computer (the order in which the computer looks for startup
files) starts with the floppy drive (for older computers), then is followed by
the CD or DVD drives and then the internal hard drive. This means that any time the computer starts
up it will first read any disk in the floppy drive to see if startup files are
contained there, and then moves on to the CD/DVD drive if startup files are not
found. This order can be changed by
following the steps in the tip box in section 4.3 of this
module.
In
order to boot from a disk, the computer user must have a boot disk or recovery
disk for that computer. Boot disks
contain only critical startup files, and they are best prepared and used by
experienced computer technicians. They
can also be used as a part of the reimaging process, described below. Recovery disks used to come standard with all
new computers. In recent years, however,
the computer manufacturers have instead set up systems for users to create their
own recovery disks when first using a new computer. If a computer lab manager has recently
received new computers, he or she would be wise to create recovery disks before
putting the computers into general use.
4.6.6. Reimaging Computers
One
very handy “tool” for a computer lab manager to have for managing software
problems is disk reimaging (also known as cloning). The idea here is that a lab manager can
create a complete copy of a computer’s system when it is running
perfectly. These copies, which are known
as images or clones, include all software and files. The purpose of having these images is that
when a computer in the computer lab fails due to a software problem, the
computer lab manager can choose to reimage or clone the computer using the
perfect image, rather than uninstalling and reinstalling each software program
separately until the problem is identified and fixed. One type of proprietary reimaging software is
called Symantec Ghost (see www.ghost.com). A common open source reimaging program is
called Clonezilla (see www.clonezilla.org).
Before
creating an image, the computer lab manager should make sure that the computer
is set up “perfectly” and free of any malware.
Images are best made when a computer is newly setup, before it has seen
much use. However the lab manager should
make sure that the computer that is being used to create the image has already
been loaded with all 
the utilities, productivity software and educational
materials that are commonly used in that computer lab. The tip box here suggests some items. The computer lab manager should also make
sure that all of the programs have been updated fully, as discussed in section 5.6.2 of this module.
the utilities, productivity software and educational
materials that are commonly used in that computer lab. The tip box here suggests some items. The computer lab manager should also make
sure that all of the programs have been updated fully, as discussed in section 5.6.2 of this module.
Before
creating an image, a computer lab manager needs to consider two questions: 1.
What drive should be used to boot the computer from while creating the image
and reimaging a computer? And 2. What
media will be used to store the computer image?
The answers to these questions will depend on the imaging program being
used and the limitations of the computer system. When using Clonezilla Live, for example, the
program can be downloaded from the Internet to fit onto a bootable CD ROM
disk. Therefore one option is to boot
the computers from the Clonezilla Live CD.
The image that is created then can be easily stored on a flash drive or
external hard drive, using the USB port.
For complete instructions on using Clonezilla Live, please see the www.clonezilla.org website.
Once
an image has been created, it can be stored until needed to reimage the
computer it was created from or any other computer with identical
hardware. This is very useful for a
computer lab that received a donation of ten identical computers, for example. If using the image to reimage another
computer in a computer lab, however, there are some important points that the
computer lab manager needs to keep in mind.
The first is computer identity.
Any cloned computers will have the same name and Security Identification
(SID). The computer lab manager should
change the name of the computer after reimaging by right clicking on the Computer (or My Computer) icon or menu item and then selecting Properties. The computer SID can remain unchanged.
The
second important point is that the software license keys will be the same for
all cloned computers. If the computers
are running proprietary software, the computer lab manager needs to be aware of
how many computers are permitted to run on a single license. If a license is only for an individual
computer, the computer lab manager will need to buy additional license keys for
the software in question and enter the proper license keys into the computer.
4.7.1. Tools and Safe Repair Practices
What
tools will a computer lab manager need to perform basic hardware repair? This will depend on the type of computers being
worked on, and also on what tools are locally available. However, good quality screwdrivers in
different sizes will be on every lab’s equipment list. The majority of the screws encountered in
computers are of the Phillips type (the screw head has an X shape on the top),
but flat head and hex head screws may also occur. A computer lab manager can look and see what
types of screws are in use in the lab before making a purchase. Magnetic tip screwdrivers can be very useful
since the screws will stay magnetically attached to the screwdriver while the
lab manager locates the screw hole.
However it is very important to avoid touching the tips of magnetic
screwdrivers to RAM or hard drives, since the magnetic storage on those devices
could be damaged. A pair of needle nose
pliers may also be useful to assist when working in narrow spaces.
For
cleaning computer parts, a computer lab manager will need some method for
blowing dust out of computer hardware.
If an electric blower is available, this is a very good option. Otherwise a hand operated blower (with a
bellows or bladder attached to a narrow outlet) will do. If affordable, a computer lab manager can
also purchase compressed air in aerosol cans.
For dusting and cleaning computer and monitor cases, a lint free cloth
is best. Screens (LCD and CRT) can be
cleaned with slightly damp cloths or with small amounts of mild cleaning
solutions that have been reported to be safe for computer monitors. If RAM
needs to be cleaned, isopropyl alcohol and lint free swaps can be used.
There
are several safety concerns (both for the lab manager and for the computer
equipment) that need to be attended to.
They are listed below.
·
Working Environment. The computer work room should be clean, well
organized and properly lit. Avoid
hazards to the computer (such as dust or moisture) and hazards to the workers
(such as electrical cords that can be tripped over). The lab manager should also consider good
organization as a way to make repair work more efficient. It should be easy for a worker to return to a
project without any difficulty finding the parts involved.
·
Static Electricity. Static electricity
discharges (sparks) can be significantly damaging to computer equipment such as
RAM, CPUs and motherboards. Therefore it
is important for the computer lab manager to ground him or herself before
working with computer equipment. The tip
box here gives some suggestions.
If electrostatic mats or grounding wrist straps are available locally,
these items can also be used to prevent electrostatic shocks.
Static Electricity. Static electricity
discharges (sparks) can be significantly damaging to computer equipment such as
RAM, CPUs and motherboards. Therefore it
is important for the computer lab manager to ground him or herself before
working with computer equipment. The tip
box here gives some suggestions.
If electrostatic mats or grounding wrist straps are available locally,
these items can also be used to prevent electrostatic shocks.
·
Electrical Shock. Before opening up the case of a computer or
any other electronic device or cleaning it with any fluid, make sure that it is
unplugged. Otherwise, electricity can be
transmitted through the electronic device and into the worker’s body. This can cause severe injury or even death. Laptop batteries should also be removed
before performing any laptop computer repairs.
It is best to avoid attempting repairs on computer monitors,
particularly CRT monitors due to a risk of a dangerous electrical discharge.
4.7.2. Hardware Repair Planning and Strategy
Before
beginning a computer hardware repair, it is important to make sure that the
repair is necessary and that a repair plan is in place. To determine if a repair is necessary, the lab
manager should have worked through the troubleshooting steps described earlier
in this module. If a computer is still
operational, the lab manager should be using software tools to diagnose (and in
some cases repair) problems before physically opening the computer. For example, the Device Manager (described in
section 5.5) can be used to check for hardware faults,
and a hard drive diagnostic tool (such as Chkdsk, described in section 5.1.4) can be used to determine if a hard drive
needs to be replaced. Also remember that
error messages can give important information about what is wrong with a
computer.
When
developing a repair plan, the computer lab manager needs to know which parts
are going to be replaced and how to find and remove those parts from the
computer. It is also important to have
replacement parts on hand that are known to be in good condition.
Part
re-seating and part swapping are both good strategies to keep in mind when
repairing computers. Re-seating means
removing or disconnecting a part, cleaning it if appropriate, and correctly
replacing the part. Sometimes a computer
part can function poorly just because a connection is loose or dirty, and
re-seating will improve its performance.
If this does not solve a problem, a good next step is to try to swap the
same part with one from a functioning computer.
This can be a useful part of troubleshooting, since it helps the lab
manager identify whether or not that part truly is the source of a computer
problem, before a purchase is made.
People who are just learning about computer repair can easily practice
this with peripheral devices. If a
desktop computer keyboard appears not to be working, for example, try replacing
it with a keyboard that is known to work properly.
Below
are descriptions of some of the most common hardware repairs, including key
steps in the process. In all cases,
however, the lab manager who is just beginning to work on computer repair would
be encouraged to complete these repairs alongside a more experienced technician
as they gain skill and confidence. If
the lab manager has an opportunity (through this course or any other) to attend
a hardware repair training session, he or she should insist on being involved
in as much hands-on training as is possible.
Replacing
a Power Supply. For desktop computers
in developing countries, power supply failure is a common problem. This is due to an uneven or “dirty” voltage
and power surges. Before replacing a
power supply, a lab manager should make sure that it truly is dead by following
the tip box in section 5.2.2. Then follow the steps below:
1.
Unplug
the power cord from the back of the computer case.
2.
Open
up the computer case. The method varies
with the brand and model of computer, but often involves laying the case on its
side and opening up the side panel. Some
computer cases use screws and others have buttons to press that release one
side panel.
3.
Find and unscrew all
of the screws attaching the power supply to the back of the case. Usually there will be four screws, located
just outside the cut out in the case (or along the mesh grid) where the power
supply is found. Do not disconnect the
various cables yet. Move the dead power
supply as far out of the way as the cables will allow. You may be able to set the power supply on
top of the case (see photo).
Find and unscrew all
of the screws attaching the power supply to the back of the case. Usually there will be four screws, located
just outside the cut out in the case (or along the mesh grid) where the power
supply is found. Do not disconnect the
various cables yet. Move the dead power
supply as far out of the way as the cables will allow. You may be able to set the power supply on
top of the case (see photo).
4. Install the new
power supply and screw in all screws.
5.
One
by one, detach the cables from the old power supply to the various computer
components, and replace them with the cables from the new power supply. Doing this one by one will help make sure
that no components are missed. There
will be power supply connectors for the motherboard and all drives. When removing the cables, keep an eye out for
latches that need to be depressed to release the connector. All of the connectors should only fit in one
direction, and with little force. If a
connector does not attach easily, make sure that it is properly aligned before
pushing harder.
Replacing a Hard
Drive.
Replacing a faulty hard drive is not a
difficult task, but a lab manager should have done some investigative work
first to determine if the hard drive is faulty.
This could include running the Chkdsk utility, as described in section 5.1.4, listening for unusual noises coming from the
hard drive and also checking to make sure the cables to the hard drive are
still fully connected. The computer may
also present error codes during start up that indicate a problem with the hard
drive. Before replacing a hard drive, it
is worth trying to reset the BIOS to the default settings to see if this fixes
the problem. To do this, enter the BIOS
during computer start up (as described in section 4.3)
and choose the default settings. Then save
the new settings and exit. The onscreen
instructions in the BIOS program will guide the computer lab manager through
these steps.
Once
it has been determined that a hard drive problem is likely, the computer lab
manager should follow the steps below to replace the hard drive with a known
working hard drive.
1.
Disconnect the
computer case from electricity and then open the computer case (as described
above).
Disconnect the
computer case from electricity and then open the computer case (as described
above).
2.
Locate
the hard drive. It will likely be found
in a metal case or cage near the front of the computer case, below the other
drives. It could be mounted directly on
the cage or it could be mounted on rails that will slide out of the case (see
photo).
3.
Unscrew
the hard drive from the cage or slide the rails out and unscrew the hard drive
from the rails.
4.
Remove
the long ribbon cable from hard drive.
There may have been a small amount of glue used to hold the ribbon in
place that will also need to be removed.
Then remove the smaller power cable.
If it is difficult to remove, gently wiggle the connector back and forth
along its long axis as you pull. Note
the orientation of the connector (which end is the red wire on?) to make sure
that the new hard drive is connected in the same manner.
5.
If
there are two hard drives in a computer, one is called the master and the other
the slave. On older hard drives, an
electrical connection needs to be changed to indicate whether the hard drive is
a master or a slave. If the hard drive
being installed has not been used before, it will be correctly set as a master
(or also on the acceptable “Cable Select” setting, used when the ribbon cable
has two connectors – one for a master and one for a slave). If the hard drive has been previously used as
a slave, however, it will need to be changed to a master. To do this, look for a diagram on the hard
drive that shows the pattern for connecting (jumping) two of the eight pins
located between the two cable connectors on the front end of the hard
drive. Then using needle nose pliers,
pull off the jumper that is connecting two of the pins and replace it to
connect the proper pair.
6.
Connect
the cables to the new hard drive. Then
screw the hard drive back on to the rails and slide the rails into position (or
screw the hard drive directly to the cage if there are no rails). Make sure that all of the other ribbons and
cables are as they were found. Close the
case and the repair is complete. Note
that if any new noises or problems appear after the installation, it is
possible that another device or cable was disrupted during the repair and needs
to be reattached or reseated.
Replacing a Hard
Drive for a Laptop Computer. Hard
drives for many laptop computers can be replaced quite easily because the
manufacturers have made the hard drives accessible from hatches on the
underside of the computer. To replace the
hard drive on a laptop with an accessible hard drive follow the steps below:
1.
Remove the laptop
battery before making this (or any other) laptop repair. This is important in order to avoid
electricity from the battery flowing through the computer during repair, which
could be damaging to computer components.
The technique for removing the battery depends on the make and model of
the laptop, but often involves unlocking the battery at one or two points (on
the underside of the computer) and then sliding it out.
Remove the laptop
battery before making this (or any other) laptop repair. This is important in order to avoid
electricity from the battery flowing through the computer during repair, which
could be damaging to computer components.
The technique for removing the battery depends on the make and model of
the laptop, but often involves unlocking the battery at one or two points (on
the underside of the computer) and then sliding it out.
2.
With
the laptop resting upside down on a table, find the hard drive compartment and
unscrew the screw or screws holding the lid in place. Remove the lid and examine how the hard drive
is attached to the computer. Most likely
you will see that the hard drive is attached to a cage or brackets that will
slide out with the hard drive (see photo).
3.
Slide
out the assembly containing the hard drive in its cage or brackets. You may have to push the assembly in or lift
it up first in order to clear anything else used to hold the assembly in place.
4.
Remove
any screws attaching the laptop to its cage/brackets, remove the damaged hard
drive, replace it with a functioning laptop hard drive and then retighten all
screws.
5.
Slide
the assembly back into the laptop and secure it as it was previously. Make sure
that you push hard enough to reattach the hard drive to the power and data
connectors. Push horizontally (or as
close as possible to horizontally) when reconnecting.
6.
Close
the hard drive compartment and replace all screws. Then replace the laptop battery, turn the
computer over and restart it.
Replacing RAM. As discussed in section
5.1.7, a lab manager may want to add RAM to speed up a slow computer. RAM also can fail or come loose from its
housing and need to be reseated. If a
lab manager has decided that a computer needs new or additional RAM, it is
important to make sure that the RAM used is compatible with the computer
system. There are several online RAM
sales companies that will identify the appropriate RAM if a user inputs the
computer make and model. Two example
companies are Corsair (www.corsairmemory.com)
and Crucial (www.crucial.com). Once
the RAM has been obtained, the lab manager should follow the steps below to
replace the RAM. Please Note: RAM is very
easily damaged by electrostatic charges, so it is very important for the user
to be grounded before picking up RAM.
Also RAM should only be handled by the edges.
1.
Open the computer
case as previously described. Find the
RAM slots (long parallel connectors). Note which slots are occupied and if the
slots are numbered (at the ends). If the
slots are not numbered, the slots closest to the processor are probably the
lower numbered slots and should be filled first.
Open the computer
case as previously described. Find the
RAM slots (long parallel connectors). Note which slots are occupied and if the
slots are numbered (at the ends). If the
slots are not numbered, the slots closest to the processor are probably the
lower numbered slots and should be filled first.
2.
Simultaneously
push down and out on both retaining clips (on each end) of a RAM slot to remove
the old RAM. Note the orientation of the RAM so that the replacement RAM can be
put in facing the same direction. There
should be some notches on the bottom edge of the RAM that can be used as a
guide.
3.
Gently
place the new RAM in the socket and press down firmly on the top of the RAM at
both ends (see photo). When the RAM module
is correctly seated, the retaining clips will automatically close.
4.
Close
the computer case as previously described.
Replacing Laptop
RAM. Laptop computers have a compartment on the
back side designed for accessing RAM.
When the screws for this compartment are removed (but don’t forget to
remove the laptop battery first for safety reasons!), the RAM should be
visible. For some laptops, however, only
the slot for expansion (extra) RAM is visible.
In these cases the rest of the RAM is can be accessed by removing the
keyboard, a more difficult task (discussed below). Laptop RAM rests horizontally, with the slot
on one end. To install RAM, hold the RAM
by its edges, and bring it up towards its slot at about a 30 degree angle (see
photo). Then gently push the RAM in
while flattening out the angle.
Other Laptop
Repairs. It is possible to
replace the keyboard, individual keys or the screen on a laptop with only a
moderate amount of difficulty. The
challenge, however, is that every different model of laptop requires a
different method for accessing and removing these parts. Either a lab manager should watch other
people do these repairs and learn from them, or find information on the Internet
for the specific desired repair.
Specific searches should result in detailed diagrams, descriptions or
videos. For example, if someone wanted
to replace a key on a Dell laptop, the search terms “replacing laptop keys
Dell” will yield useful results.
Similarly, if someone wanted to replace the entire keyboard on a Toshiba
laptop, the search terms “replacing laptop keyboard Toshiba” will suffice. In general when performing laptop repairs,
the computer lab manager should remember these guiding principles:
1.
Always
remove the battery first for safety reasons.
2.
Keep
note of what screws are removed and in what order. Also keep track of the actual screws!
3.
When
taking a laptop apart, be slow and mindful of the process. This will make it
easier to put the computer back together afterwards. For complicated repairs, consider keeping
notes of the steps performed.
Problems with a
printer are generally in the following categories:
1.
Software
problems with the computer, including problems with the printer driver
2.
Poor
connections or electrical problems with the printer
3.
Insufficient
ink
4.
Paper
jam
5.
Printer
hardware problems
All of these except
for number five are easily managed by a trained computer lab manager. The tip box here gives some suggestions
for troubleshooting a faulty printer.
In
concluding this module, it is important to recognize that not all computer
problems can or should be fixed.
Sometimes computers become too old or obsolete to make the effort of
repairing them worthwhile, and some repairs (such as repairs to CRT computer
monitors) are not advisable except by experts.
Due to these realities, computer labs often have a collection of old and
broken computers and peripheral equipment that develops and increases over the
years. This equipment is collectively
known as electronic waste or e-waste. In
many developing countries e-waste is a problem because the equipment can
contain hazardous materials and there often are not recycling or waste
facilities that are capable of managing these hazardous materials properly.
The
first step in managing e-waste is to try to reduce the amount of it that is
produced by a computer lab. A lab
manager can do this by avoiding accepting donations of equipment that is
already very old or obsolete, since this equipment will not remain useful for
long. A lab manager can also make sure
that existing equipment is maintained well so that it remains useful for a
longer period of time. The computer lab
manager should also work with any organizations donating computers to discuss
the e-waste problem and strategize how the computers will be disposed of
properly when they are no longer useful.
Options
for proper disposal of e-waste will vary from country to country. In some countries there will be private
companies that collect e-waste, and in others there will be government projects
for e-waste disposal. Larger non-profit
organizations that donate used computer equipment often have plans for
collecting and managing e-waste. If no
e-waste options exist in a particular country, several computer projects could
team together to ship a container of e-waste to an e-waste facility in a
neighboring country. One e-waste
management facility that accepts shipments is Desco Electronic Recyclers in
South Africa (www.desco.co.za).