Download CHAPTER 8 System Resources Optimization

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CHAPTER 8
System Resources Optimization
Chapter 8
Learning Objectives
After completing this lesson, you should be able to:
i.
ii.
iii.
iv.
Explain computer resources
Explain the effects caused by file fragmentation in the PC.
Explain the methods of optimizing the computer performance.
Describe the different types of computer security threats.
Disk Fragmentation
After a period of time of use, hard disks will have disk fragmentation. It refers to the condition
of a disk in which files are divided into pieces, scattered around the disk. Fragmentation is
caused by frequent use of a disk for creating, deleting, and modifying files. At some point, the
OS needs to store parts of a file in scattered clusters. The result is slow performance of the disk.
The OS needs to search through different parts of the disk to put together a single file.
In visual form, we can imagine the condition to be like this:
The red portions represent fragmented files.
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To speed up a PC, an OS can defragment the hard disk. A defragmented hard disk will look like
this:
To defragment a hard drive, for Windows OS, go to [Control Panel],[ System and Security], and
choose [Defragment your Hard drive].
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PC Optimization
PC Optimization refers to getting the PC to operate at maximum efficiency and speed in
retrieval, storage or program execution. Once optimized, a PC will run smoother and faster with
less chances of stalling.
There are four ways of optimizing a PC:
 Software Optimization
Software can be optimized by good programming techniques so that
- it operates faster, or
- uses less RAM
 Operating System Optimization
OS can be optimized by
- reducing running processes
- defragmenting the hard disk
- reducing unneeded system boot processes, etc
 Hard disk Optimization
A hard disk will operate faster when it has less files. The number of unnecessary files on
your hard disk can be removed using a utility known as Disk Cleanup Wizard. It removes
temporary files, empties the Recycle Bin, and removes system files and other items that
you no longer need.
 Optimization using Virtual Memory
When too many programs are running, RAM may be used up. That slows down the PC
and may even stall it. Windows OS has a feature known as Virtual Memory. When RAM
is used up, it uses hard disk space to act like RAM. The size of this virtual memory can be
set.
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Virtual Memory Setting – Windows 7
If you receive warnings that your virtual memory is low, you'll need to increase the minimum
size of your paging file. Windows sets the initial minimum size of the paging file equal to the
RAM installed on your computer, and the maximum size equal to three times the RAM. If you
see warnings at these recommended levels, then increase the minimum and maximum sizes.
Open System by clicking the Start button Picture of the Start button, right-clicking Computer,
and then clicking Properties. In the left pane, click Advanced system settings. Administrator
permission required If you're prompted for an administrator password or confirmation, type
the password or provide confirmation.
On the Advanced tab, under Performance, click Settings.
Click the Advanced tab, and then, under Virtual memory, click Change.
Clear the “Automatically manage paging file size for all drives” check box.
Under Drive [Volume Label], click the drive that contains the paging file you want to change.
Click Custom size, type a new size in megabytes in the Initial size (MB) or Maximum size (MB)
box, click Set, and then click OK.
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Security Threats
Computer security means to protect information. It deals with the prevention and detection of
unauthorized actions by users of a computer. Personal PCs and commercial servers contain
sensitive and confidential information. Criminals will want to get hold of these information for
their crimes. For instance, there are criminals who steal userids and passwords of credit card
accounts, then make purchases online using these accounts. If they can steal bank account
information, they can take all the money from an account. Any form of intended crime targeted
at computer systems are known as security threats.
Computers and computer networks need security features to ensure that,
 no unauthorized users get into the system
 only authorized users can enter and use the system
 data are kept safe
 applications running normally
The main areas of threats to guard against are:
 internal threats – employees who have access to the system
 external threats – unauthorized users who may try to hack the system
Damages that may result from these threats include:
 loss of data
 corruption of data
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loss of equipment
shutdown of operation
drop in system performance
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The five most common security threats to PCs are:
 Computer virus
 SPAM
 PHISHING
 Spyware
 Keystroke Logging
Security Threat #1 : Computer Virus
A computer virus is a piece of software that can replicate itself and infect a computer without
the user knowing. It can be transmitted over,
a computer network or the Internet, or
removable media such as CDs or memory sticks.
Viruses can cause following damages:
- delete files
- reformat the hard disk
- replicate themselves
- display texts or videos
- cause erratic behavior of the PC
- crash the OS
- cause loss data.
To safeguard PCs, viruses must be prevented, detected and removed using antivirus software.
The two most common methods used to detect viruses are:
 compare virus signatures
A list of virus signatures is stored in a database. The antivirus examines computer files
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and compares them with these signatures. If they match, it is a virus. This method is
only effective against known viruses. The database must also be updated regularly.
detect behavior of virus
The virus is detected by its behavior using a heuristic algorithm. This method can detect
viruses that are not known.
Security Threat #2: SPAM
SPAM refers to a same message sent to a large number of internet users. The message is
unsolicited. It can be sent over any media including email, online forums, blogs, etc. The main
aim of SPAM is for free advertising. A person who creates a SPAM is called a spammer. When
spamming floods the email inbox of a user, he will have to waste time and effort deleting all the
unwanted messages. Anti-spam software or filers are used to detect and prevent spam. One
example is Symantec.
Some email software are able to detect commonly used spam patterns, push these spam emails
to a Spam inbox. Users can also mark some emails as spams. One example is Gmail by Google.
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Security Threat #3: PHISHING
Phishing is the attempt to acquire sensitive information such as usernames, passwords, and
credit card details. The aim is to mislead you into giving these information online.
Phishing emails can contain links to websites that are infected with malware. For example, an
email claims to be sent from a bank. In the email, you are asked to click on a link. The link will
bring you to a fake website where you are asked to login to your bank account. One you do
that, your password will be given to the person behind the phishing.
Banks provide an additional step for login, viz,
 security code from security token
 security code sent via SMS
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The following actions can be taken against phishing:
 never login to a website via a email link
 always login via a website by going entering its url
 never enter your id and password if you are suspicious
 insist on additional security code
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One example of a phishing emails. Usually there is promise of rewards, money, etc.
Spyware
A spyware is a type of software that goes into a computer, without the owner knowing it. It will
then transmit data from the computer to the hacker. It can also take over control of a
computer. It is usually installed when you have requested for some free programs online.
Spywares can collect the following,
 user information
 user surfing patterns
 sensitive data (passwords, bank account information, etc)
 change computer settings
 change web browser settings
Software used to detect and remove spyware are known as anti-spyware. Anti-spyware
programs monitor data coming from,
 emails and websites
 downloads of files
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Examples of anti-spyware software are,
 Norton AntiSpyware
 PC Tools Spyware Doctor
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Do you know of any others? If yes, state them here:
__________________________
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Keystroke Logging
Keystroke Logging is the action of recording the keys struck on a keyboard. It can be done using
hardware devices or software. It can be done with or without the user’s knowledge.
Hackers can install a keystroke logging software on a computer manually or via a virus. By
recording your keystrokes, hackers can obtain your sensitive data, such as,
 Passwords
 bank security codes
 credit card numbers
Precautions to take against keystroke logging include,
 install anti-spyware program
 beware of installation of freeware
 beware of allowing strangers to use your computers
 check the security level of the internet browser used
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