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1. List of Probable questions
1. What are the types of Operating System ?
Real-time Operating System: It is a multitasking operating system that aims at
executing real-time applications. Real-time operating systems often use specialized
scheduling algorithms so that they can achieve a deterministic nature of behavior. The
main object of real-time operating systems is their quick and predictable response to
events. They either have an event-driven or a time-sharing design. An event-driven
system switches between tasks based of their priorities while time-sharing operating
systems switch tasks based on clock interrupts.
Multi-user and Single-user Operating Systems: The operating systems of this type
allow a multiple users to access a computer system concurrently. Time-sharing system
can be classified as multi-user systems as they enable a multiple user access to a
computer through the sharing of time. Single-user operating systems, as opposed to a
multi-user operating system, are usable by a single user at a time. Being able to have
multiple accounts on a Windows operating system does not make it a multi-user
system. Rather, only the network administrator is the real user. But for a Unix-like
operating system, it is possible for two users to login at a time and this capability of
the OS makes it a multi-user operating system.
Multi-tasking and Single-tasking Operating Systems: When a single program is
allowed to run at a time, the system is grouped under a single-tasking system, while in
case the operating system allows the execution of multiple tasks at one time, it is
classified as a multi-tasking operating system. Multi-tasking can be of two types
namely, pre-emptive or co-operative. In pre-emptive multitasking, the operating
system slices the CPU time and dedicates one slot to each of the programs. Unix-like
operating systems such as Solaris and Linux support pre-emptive multitasking.
Cooperative multitasking is achieved by relying on each process to give time to the
other processes in a defined manner. MS Windows prior to Windows 95 used to support
cooperative multitasking.
Distributed Operating System: An operating system that manages a group of
independent computers and makes them appear to be a single computer is known as a
distributed operating system. The development of networked computers that could be
linked and communicate with each other, gave rise to distributed computing.
Distributed computations are carried out on more than one machine. When computers
in a group work in cooperation, they make a distributed system.
Embedded System: The operating systems designed for being used in embedded
computer systems are known as embedded operating systems. They are designed to
operate on small machines like PDAs with less autonomy. They are able to operate with

2. a limited number of resources. They are very compact and extremely efficient by
design. Windows CE, FreeBSD and Minix 3 are some examples of embedded operating
systems.
2. Difference between FAT and NTFS.
NTFS
1)allows access local to w2k w2k3 XP win NT4 with SP4 & later may get access for somefile.
2)Maximum size of partition is 2 Terabytes & more.
3)Maximum File size is upto 16TB.
4)File & folder Encryption is possible only in NTFS.
FAT 32
1)Fat 32 Allows access to win 95 98 win millenium win2k xp on local partition.
2)Maximum size of partition is upto 2 TB.
3)Maximum File size is upto 4 GB.
4)File & folder Encryption is not possible.
3. Enhancements in Windows 2003 from Windows 2000
4. Enhancements in Windows 2003 from Windows NT
5. What is Active Directory ?
An active directory is a directory structure used on Microsoft Windows based computers and
servers to store information and data about networks and domains. It is primarily used for
online information and was originally created in 1996. It was first used with Windows 2000.
An active directory (sometimes referred to as an AD) does a variety of functions including
the ability to provide information on objects, helps organize these objects for easy retrieval
and access, allows access by end users and administrators and allows the administrator to
set security up for the directory.
6. Types of Firewall
Network-Level Firewalls
The first generation of firewalls (c. 1988) worked at the network level by inspecting packet
headers and filtering traffic based on the IP address of the source and the destination, the

3. port and the service. Some of these primeval security applications could also filter packets
based on protocols, the domain name of the source and a few other attributes.
Network-level firewalls are fast, and today you'll find them built into most network
appliances, particularly routers. These firewalls, however, don't support sophisticated rule-
based models. They don’t understand languages like HTML and XML, and they are capable
of decoding SSL-encrypted packets to examine their content. As a result, they can’t validate
user inputs or detect maliciously modified parameters in an URL request. This leaves your
network vulnerable to a number of serious threats.
Circuit-Level Firewalls
These applications, which represent the second-generation of firewall technology, monitor
TCP handshaking between packets to make sure a session is legitimate. Traffic is filtered
based on specified session rules and may be restricted to recognized computers only.
Circuit-level firewalls hide the network itself from the outside, which is useful for denying
access to intruders. But they don't filter individual packets.
Application-Level Firewalls
Recently, application-level firewalls (sometimes called proxies) have been looking more
deeply into the application data going through their filters. By considering the context of
client requests and application responses, these firewalls attempt to enforce correct
application behavior, block malicious activity and help organizations ensure the safety of
sensitive information and systems. They can log user activity too. Application-level filtering
may include protection against spam and viruses as well, and be able to block undesirable
Web sites based on content rather than just their IP address.
If that sounds too good to be true, it is. The downside to deep packet inspection is that the
more closely a firewall examines network data flow, the longer it takes, and the heavier hit
your network performance will sustain. This is why the highest-end security appliances
include lots of RAM to speed packet processing. And of course you'll pay for the added
chips.
Stateful Multi-level Firewalls - SML vendors claim that their products deploy the best
features of the other three firewall types. They filter packets at the network level and they
recognize and process application-level data, but since they don't employ proxies, they
deliver reasonably good performance in spite of the deep packet analysis. On the downside,
they are not cheap, and they can be difficult to configure and administer.
7. Difference between Hardware and Software Firewall.
Hardware Firewalls
You can buy a hardware firewall as a stand-alone product, but more recently hardware
firewalls are typically found in broadband routers, and should be considered an important
part of your system and network set-up, especially for anyone on a broadband connection.
Hardware firewalls can be effective with little or no configuration, and they can protect
every machine on a local network. Most hardware firewalls will have a minimum of four

4. network ports to connect other computers, but for larger networks, business networking
firewall solutions are available.
A hardware firewall examines data packet to determine their source and destination. It
compares this information to a set of predefined or user-created rules that determine
whether the packet should be routed to its destination or blocked and dropped.
A person with general computer knowledge can plug in a firewall, adjust a few settings and
have it work. To ensure that your firewall is configured for optimal security and protect
however, you should learn its specific features, how to use them, and how to test the
firewall to make sure it's protecting your network.
Not all firewalls are created equal, and it's important to read the manual and
documentation. Additionally the manufacturer's Web site usually provides a knowledgebase
or FAQ to help you get started. If the terminology is a too tech-oriented, you can also use
the Webopedia search to help you get a better understanding of some of the computer
terms you will encounter while setting up your hardware firewall.
To test your hardware firewall security, you can purchase third-party test software or search
the Internet for a free online-based firewall testing service. Firewall testing is an important
part of maintenance to ensure your system is always configured for optimal protection.
Software Firewalls
Most people prefer a software firewall. You install a software firewall on individual
computers (just like any software), and you can customize its function and protection
features. A software firewall protects your computer from outside attempts to control or
gain access your computer, and, depending on which firewall you choose, it could also
provide protection against the most common Trojan programs or e-mail worms.
Many software firewalls have user-defined controls for setting up safe file and printer
sharing and to block unsafe applications from running on your system. Additionally,
software firewalls may also incorporate privacy controls, Web filtering (i.e., making certain
types of sites – adult content, gambling, shopping, for example -- inaccessible) and more.
The downside to software firewalls is that they only protect the computer they are installed
on, not a network, so each individual computer needs to have a software firewall installed
on it.
Like hardware firewalls, there is a vast number of software firewalls from which to choose.
To get started you may wish to read reviews of software firewalls and search out the
product Web site to glean some information first. Because your software firewall will always

5. be running on your computer, you should make note of the system resources it requires and
any incompatibilities with your operating system. A good software firewall will run in the
background on your system and use only a small amount of system resources. It's
important to monitor a software firewall once installed and to download any updates
available from the developer.
The best way to protect your computer and network is to use both types of firewalls, as
each offers different but much-needed security features and benefits. Updating your firewall
and your operating system is essential to maintaining optimal protection, as is testing your
firewall to ensure it is connected and working correctly.
8. Name the seven layers of OSI model.
Layer 7:Application Layer
Defines interface to user processes for communication and data transfer in network
Provides standardized services such as virtual terminal, file and job transfer and operations
Layer 6:Presentation Layer
Masks the differences of data formats between dissimilar systems
Specifies architecture-independent data transfer format
Encodes and decodes data; Encrypts and decrypts data; Compresses and decompresses
data
Layer 5:Session Layer
Manages user sessions and dialogues
Controls establishment and termination of logic links between users
Reports upper layer errors
Layer 4:Transport Layer
Manages end-to-end message delivery in network
Provides reliable and sequential packet delivery through error recovery and flow control
mechanisms
Provides connectionless oriented packet delivery
Layer 3:Network Layer
Determines how data are transferred between network devices

6. Routes packets according to unique network device addresses
Provides flow and congestion control to prevent network resource depletion
Layer 2:Data Link Layer
Defines procedures for operating the communication links
Frames packets
Detects and corrects packets transmit errors
Layer 1:Physical Layer
Defines physical means of sending data over network devices
Interfaces between network medium and devices
9. How to enable Firewall in Windows XP.
A. Click Start, Control Panel, double–click Network Connections, right-click the
desired connection, Properties, Advanced tab, Under Internet Connection Firewall,
uncheck or check the Protect my computer and network by limiting or
preventing access to this computer from the Internet check box.
10. How to Disable Firewall in Windows XP
11. Minimum System requirement of Windows XP, Vista, 2003 and 2008
12. Explain ping command.
Ping is a basic Internet program that allows a user to verify that a particular IP address
exists and can accept requests.
Ping is used diagnostically to ensure that a host computer the user is trying to reach is
actually operating. Ping works by sending an Internet Control Message Protocol (ICMP) Echo
Request to a specified interface on the network and waiting for a reply. Ping can be used for
troubleshooting to test connectivity and determine response time.
13. pst file location
Win xp – c:doc & setting user name Local SettingsApplication DataMicrosoftOutlook
14. What is a port number ?
a port number is part of the addressing information used to identify the senders and receivers
of messages. Port numbers are most commonly used with TCP/IP connections
15. Where is the HOSTS file located
C: windows system32driversetc

7. 16. Lan cable code –
Straight – 1. White orange
2. Orange
3. White green
4. Blue
5. White blue
6. Green
7. White brawn
8. Brawn
Cross - 1–3
2-6
3–1
4–4
5–5
6–2
7–7
8 – 8.
17. type of backup –
Normal. - When an administrator chooses to use a normal backup, all selected files and folders
are backed up and the archive attribute of all files are cleared. A normal backup does not use the
archive attribute to determine which files to back up. A normal backup is used as the first step of any
backup plan
Copy. - Copy backup is a backup that copies all selected files but does not mark each file as
having been backed up. In other words, the archive attribute is not cleared. Copying can be

8. carried out between normal and incremental backups because copying does not affect these
other backup operations.
Incremental. - A backup of those files which have changed since the last backup of any type.
An incremental backup is the fastest backup and requires the least storage space on the
backup media. However, incremental backups also require the longest time and many tapes
to restore.
Differential - A backup of those files which have changes since the last full backup. Should be
performed at regular intervals.
Daily. - Daily backup refers to making daily copies of data so that these additional copies
may be used to restore the original after a data loss event. Daily backups can also be
combined with weekly or monthly full backups, according to the backup scenario used
18. command to create domain – dcpramo.
The Active Directory Database is Stored in %SYSTEM ROOT%NDTS folder. the active
directory uses the sysvol folder as well
The file is called as ntds.dit. Along with this file there are other files also present in this folder.
The files are created when you run dcpromo.
What is DNS?
Domain Name System (DNS) is a database system that translates a computer's fully qualified
domain name into an IP address.

9. 19.
20. Explain different RAID levels
21. Explain APIPA, IP address and Subnet mask
22. Difference between IP v4 and IP v6
23. How to remove virus from a computer
24. How to make a computer run faster
25. What is attrib command ?
26. What is edit command ?
27. How to copy a file or folder using copy command
28. How to format the hard disk using command line utilities
29. Explain Cookies
30.
31. How to boot the computer in Safe mode
32. What is Disk clean up, Disk Defragmentation, Device manager and System Restore
33. USB port Vs Firewire port
34. How to install a printer in Windows XP
35.
36. Explain mkdir, rmdir and chdir commands
37. Types of hard disk
38. Difference between primary and secondary partition
39. Types of back in Window OS
40. Differential Backup Vs Incremental Backup Vs Copy backup
41. What is remote desktop.
42. Recovery Console Vs Automated System Recovery
43. What is NTLDR file
44. How to tackle "missing NTLDR file" error
45. How many bytes are there in MAC address
46. Range of Class A IP address
47. Range of Class B IP address
48. Range of Class C IP address
49. Default subnet mask of Class A, Class B and Class C IP address
50. What is BSOD (Blue Screen of Death) and how to overcome it
51. Difference between Preferred DNS and Alternate DNS server
52. Transmission speed of T1 carrier