Maintain system integrity

ICAITSO17B

Maintain system integrity

Outline of unit content

On completion of this unit, learners should be able to protect and secure stand-alone or client server environments. Specifically, learners should be able to:

• Carry out file maintenance
• Carry out virus scanning
• Follow software copyright procedures
• Record software licences
• Restore system back-up
• Maintain Virus Protection.

Activities

Theory exercise 1

1	List 5 risks to a users computer data.
2	List 6 different types of media that can be used to backup data.
3	How would you determine what the backup requirements of an organization actually are? What factors would you consider? List 5.
4	What are the 3 different types of backup? In your answer explain the difference between them.
5	When you have set up a backup system, you would establish a record of the backup. What information do you think this record would include?
6	What does the term "Retention period" mean?
7	How do "Rotation Systems" work in relation to backups?
8	What is a Disaster Recovery Plan and what factors would you need to consider when creating this Plan?

Answers exercise 1

1.	Hardware/Software failure Unintentional file deletion File corruption Malicious software/viruses Sabotage and Theft Natural Disaster
2.	Tape Drives Floppy Disks Hard Disks Optical Media Removable Drives Network Resources
3.	How much data is to be backed up? Are unattended backups possible? How important is the data? How long can organisation work efficiently without the data? How often will backup be carried out? Who is responsible for ensuring backups are carried out? Where will backup media be stored? What backup software will be used?
4.	Full Backup - copies all files. Incremental Backup -copies all files that have changed since the last full or incremental backup. Differential Backup – copy all files that have changed since the last full backup.
5.	Date/Time of backup Backup Type Media used Name of person completing the backup Location of media Problems encountered
6.	Time period before backup media re-used Problems with short retention periods, e.g., virus infection of all backup media
7.	Media rotation Retention periods Protection against media failure
	Written plan, detailing the steps an organisation will take to restore computer operations in the event of a disaster Contact details of emergency services and essential organisation personnel Equipment shutdown procedures Employee evacuation procedures System Restore procedures Return to Normal Operations procedures Testing of Disaster Recovery Plan

Theory exercise 2

1	In Windows, what is the purpose of the Registry?
2	In Windows 95, 98 and ME what files contain the Registry?
3	What's are the differences between a Long File Name and a Short File Name?
4	What are the "attributes" of a file?
5	Which file attribute is vital to the backup process? Explain how this attribute is used in the backup process.
6	List the steps you might use to backup the registry?
7	What is the purpose of the ScanDisk utility program provided with Windows?
8	On a PC, file extensions are used. Why?
9	Which file extensions generally indicate that the file is a program file of some kind?
10	When deciding where to store organisational data on a disk, would you store it with program files?

Answers exercise 2

1.	A central storehouse of information about all aspects of the computer, particularly the computers operating system, application software, hardware and the users.
2.	System.Dat & User.Dat
3.	Prior to the release of Windows 95, all DOS and Windows 3.1 files were limited to Short File Names (SFN). SFN can have a maximum of 8 characters for the name and a maximum of 3 letters for the file extension. Long File Names (LFN) can have up to 255 characters in the file name.
4.	Read Only System Hidden Archive
5.	Archive attribute. Usually, backup programs allow a user to carry out an incremental backup (backup of any files that have changed since the last backup). The archive attribute is used for this purpose. When the backup program backs up a file, it turns off the archive attribute. If the file is then changed the archive attribute is turned back on (ready to be backed up).
6.	Use the Registry Checker program (Windows98, ME) to backup the registry. Run this program from System Tools in the Start Menu or use the Run Box and enter scanreg.
7.	To scan a disk for logical, file system errors, e.g., lost clusters, cross linked files and File Allocation Table errors. Scandisk can detect and repair these errors.
8.	File extensions are used by software applications and operating systems to indicate which files are associated with which programs, e.g., the .doc extension is usually associated with the Microsoft Word program. The program does not have to open the file and look at the internal structure of the file itself to determine if it can use the file, it simply uses the file extension. File extensions allow the user and the operating system to arrange file by type.
9.	.exe, .com, .bat
10	Data should be stored separately from program files. This helps to maintain the integrity of data and simplifies backup and restore procedures.

Theory exercise 3

1	What is a computer virus?
2	What are 3 main categories of virus?
3	What’s a “Trojan Horse” program?
4	List 7 ways of preventing viruses from infecting your computer system.
5	If you were the Assistant Computer Support Officer (say for a large company) and discovered a computer virus what action do you think you would take?
6	What are some symptoms of viruses?
7	What does a Virus Definition File contain?
8	List 5 commercial Anti-Virus programs.

Answers exercise 3

Solutions to exercise 3

There are many excellent web sites on viruses and methods of protecting computer systems against viruses. Answers to the questions in this exercise can be found at the following sites;

www.cai.com/virusinfo/
www.symantec.com/avcenter/

Theory exercise 4

1	When you purchase software (say for a large company) why do you think it is important to record software licenses?
2.	What type of information would you record in a Software Licence Log?
3.	Why was the Business Software Association of Australia, established?
4.	If you were the Assistant Computer Support Officer (say for a large company) and discovered "illegal" software on one or more computers, what action do you think you would take?
5.	How can you determine if software on a computer is "illegal"?
6.	What's the difference between shareware and freeware?
7.	When you purchase retail software, what should you receive?
8.	What is a Software Site Licence?

Answers exercise 4

Solutions to exercise 4

The Business Software Association of Australia (BSAA) was established in 1989 to combat the increasing problem of software theft and piracy in Australia. The answers to the questions in this exercise can be found at the BSAA web site. There is a particularly informative BSAA Compliance Manual with guidelines for Software Registers. The web address is www.bsaa.com.au/

Practical exercises

1	Use the backup program that comes with your operating system, e.g., Microsoft Backup, to backup selected files on a PC.
2	Rename some of the files you backed up in question 1, and then restore those files from your backup.
3	Use an archive program, e.g., Winzip, to compress a number of files over a number of floppy disks.
4	Use the internet to locate and download a free anti-virus program. Install the anti-virus program onto your computer.
5	Download a virus library update for the anti-virus program and install it.
6	Scan your system for viruses.
7	Audit your PC for illegal software.

Glossary

Backup	To copy files to another media as a precautionary measure, in case the first media fails
Boot sector Infectors	Virus that infects the boot sector of a floppy or hard disk
Differential backup	Any files that have changed since the last full backup, are duplicated
Disaster recovery plan	Detailed, written plan describing how an organisation will restore computer operations, in the event of a disaster
File infectors	Virus that attack and modify program files, usually .exe and .com files. When the program is run the virus is executed
Full backup	All files in the system, including program files and data files, are duplicated
Incremental backup	Any files that have changed since the last full or incremental backup, are duplicated
Logic bomb	Virus that activates when it detects a certain condition, e.g., a certain date
Macro viruses	Makes use of the built in programming languages in Microsoft Word and Excel (VBA). A malevolent macro that duplicate themselves into other documents and spread just like any other virus once the file has been opened
Polymorphic virus	Virus which modifies its program code every time it attaches itself to another program file
Restore	The process where files are returned from a backup to their original condition and location
Software licence	The terms and conditions under which a piece of software may be used
Trojan Horse	A destructive program that masquerades as a harmless application. While Trojan Horses do not copy themselves they can do just as much damage as viruses
Virus	A program that is loaded onto your computer without your knowledge and runs without your consent. Most viruses can also replicate themselves

Other resources

www.pcguide.com/care/bu/index.htm is a web site with very useful information on backup/restore procedures and virus prevention.

www.bsaa.com.au/ is the web site of the Business Software Association of Australia. It has a great deal of information on software licences, copyright, software piracy and guides to purchasing software.