Linux FAQ

1. What is Linux?
    Linux is an operating system based on UNIX and it was introduced by LINUS TORVALDS. it is based on the Linux Kernel and can run on different hardware platforms manufactured by Intel, MIPS, HP, IBM, SPARC and Motorola. Another popular element in Linux is its mascot, a penguin figure named Tux.

2. What is the difference between UNIX and LINUX?
    Unix originally began as a propriety operating system from Bell Laboratories, which later on spawned into different commercial versions. On the other hand Linux is free open source and intended as a no-propriety operating system for the masses.

3. What is BASH?
    BASH is short for Bourne Again Shell. it was written by Steve Bourne as a replacement to the original Bourne Shell (represented by /bin/sh). it combines all the features from the original version of Bourne Shell, plus additional functions to make it easier and more convenient to use.
It has since been adapted as the default shell for most systems running Linux.

4. What is Linux Kernel?
    Linux Kernel is a low-level systems software whose main role is to manage hardware resources for the user. It is also used to provide an interface for user-level interaction.

5. What is LILO?
    LILO is a boot loader for Linxu. It is used maily to load the Linux operating system int main memory so that it can begin its operations.

6. What is a swap space?
    A swap space is a certain amount of space used by Linux to temporarily hold some programs that are running concurrently. This happens when RAM does not have enough memory to hold all programs that are executing.

7. What is the advantage of open source?
    Open source allows your to distribute your software, including source codes freely to anyone who is interested. People would then be able to add features and even debug and correct errors that are in the source code. They can even make it run better, and then redistribute these enhanced source code freely again. This eventually benefits everyone in the community.

8. What are the basic components of Linux?
    Just like any other typical operating system, Linux has all of these components: Kernel, Shells and UGIs, system utilities, and application program. what makes Linux advantageous over other operating system is that every aspect comes with additional features and all codes for these are downloadable for free.

9. Does it help for a Linux system to have multiple desktop environments installed?
    In general, one desktop environment, like KDE or Gnome, is good enough to operate without issues. Its all a matter of preference for the user, although the system allows switching from one environment to another. Some programs will work on one environment and not work on the other, so it could also be considered a factor in selecting which environment to use.

10. What is the basic difference between BASH and DOS?
    The key differences between the BASH and DOS console lies in 3 areas:

• BASH commands are case sensitive while DOS commands are not
• BASH / character is a directory separator and \ acts as an escape character. under DOS / serves as a command argument delimiter and \ is the directory separator
• DOS follows a convention in naming files, which is 8 character file name followed by a dot and 3 character for the extension. BASH follows no such convention.

11. What is the importance of the GNU project?

     This so-called free software movement allows several advantages, such as the freedom to run programs for any purpose and freedom to study and modify a program to your needs. it also allows you to redistribute copies of a software to other people, as well as freedom to improve software and have it released to the public.

12. Describe the root account.

     The root account is like a systems administrator account and allows you full control of the system. here you can create and maintain user accounts, assigning different permissions for each account. It is the default account every time you install Linux.

13. What is CLI?

     CLI is short for Command Line Interface. This interface allows user to type declarative commands to instruct the computer to perform operations. CLI offers an advantage in the there difficult to remember commands including attributes that come with it.

14. What is GUI? 

     GUI (Graphical User Interface) makes use of images and icons that users click and manipulate as a way of communicating with the computer. instead of having to remember and type commands, the use of graphical elements makes it easier to interact with the system, as well as adding more attraction through images icons and colors.

15. How do you open a command prompt when issuing a command?

   To open the default shell(which is where the command prompt can be found) press Ctrl+Alt+F1 This will provide a command line interface(CLI) from which you can run commands as needed. 

30 FAQ on Networking

1. What is a Link?
  A link refers to the connectivity between tow devices. It includes the type of cables and protocols used to order for one device to be able to communicate with the other.

2. What are the layers of the OSI reference model?
     There are 7 OSI layers:
    1. Physical Layer,
    2. Data Link Layer
    3. Network Layer
    4. Transport Layer
    5. Session Layer
    6. Presentation Layer
    7. Application Layer

3. What is backbone network?
    A backbone network is a centralized infrastructure that is designed to distribute different routes and data to various networks. It also handles management of bandwidth and various channels.

4. What is a LAN?
   LAN is short for Local Area Network. It refers to the connection between computer and other network devices that are located within a small physical location.

5. What is a node?

A node refers to a point or joint where a connection takes place. It can computer or device that is part of a network. Two or more nodes are needed in order to form a network connection.

6. What are routers?

   Routers can connect tow or more network segments. These are intelligent network devices that store information in its routing table such as paths, hopes and bottlenecks. With this info, they are able to determine the best path for data transfer. Routers operate at the OSI Network Layer.

7. What is point to point link?
  It refers to a direct connection between tow computers on a network. A pint to point connection does not need any other network devices other than connecting a cable to the NIC cards of both computers.

8. What is anonymous FTP?
   Anonymous FTP is a way of granting user access to files in public severs. Users that are allowed access to data in these servers do not need to identify themselves, but instead log in as an anonymous guest.

9. What is subnet mask?
  A subnet mask is combined with an IP address in order to identify two parts: the extended notwork address and the host address. Like an IP address, a subnet mask is made up of 32 bits.

10. What is the maximum length allowed for a UTP cable?
  A single segment of UTP cable has an allowable length of 90 to 100 meters. This limitation can be overcome by using repeaters and switches.

11. What is data encapsulation?
    Data encapsulation is the process of breaking down information into smaller manageable chunks before it is transmitted across the network. it is also in this process that the source and destination addresses are attached into the headers, along with parity checks.

12. Describe Network Topology
    Network Topology refers to the layout of a computer network. it shows how devices and cables are physical laid out, as well as how they connect to one and another.

13. Briefly describe NAT?
   NAT is Network Address Translation. This is a protocol that provides a way for multiple computers on a common network to share single connection to the internet.

14. What is VPN?
    VPN (Virtual Private Network) a technology that allows a secure tunnel to be created across a network such as the internet.
EX: VPNs allow your to establish a secure dial-up connection to a remote server

15. What is RIP?
   RIP means Routing Information Protocol is used by router to send data from one network to another. It efficiently manages routing data by broadcasting its routing table to all other routers within the network. it determines the network distance in units of hopes.

16. What is the job of ne Network layer under the OSI model?
    The network layer is responsible for data routing, packet switching and control of network congestion. Routers operate under this layer.

17. How does a network topology affect your decision in setting up a network?
    Network topology dictates what media you must use to interconnect devices. It also serves as basis on what materials, connector and terminations that is applicable for the setup.

18. What is NIC?
    NIC means Network Interface Card. This is a peripheral card that is attached to a PC in order to connect to a network. Every NIC has its own MAC address that identifies the PC on the network.

19. What are different ways of securing a computer network?
    there are several ways to securing a computer network. Install reliable and updated anti-virus program on all computers. Make sure firewalls are setup and configured properly. user authentication will also help a lot. All of these combined would make a highly secured network.

20. What is the importance of the OSI Physical Layer?
    Physical layer does the conversion from data bits to electrical signal, and vice versa. This is where network devices and cable types are considered and setup.

21. What is WAN?
   WAN(Wide Area Network) It is an interconnection of computers and devices that are geographically dispersed. it connects networks that are located in different regions and countries.

22. How Many layers are there under TCP/IT?
    Under the TCP/IP there are 4 layers
    1. Network layer
    2. Internet layer
    3. Transport layer
    4. Application layer.

23. What is a private IP Address?
    Private IP addresses are assigned for use on intranets. These addresses are used for internal networks and are not routable on external public networks. These ensures that no conflicts are presents among internal networks while at the same time the same range of private IP addresses are reusable for multiple intranets since they do not see each other.

24. What are proxy servers and how to protect computer networks?
   Proxy servers primarily prevent external users who identifying the IP addresses of an internal network. without knowledge of the correct IP address even the physical location of the network cannot be identified. Proxy servers can make a network virtually invisible to external users.

25. What is the function of the OSI session layer?
    This layer provides the protocols and means for tow devices on the network to communicate with each other by holding a session. This includes setting up the session, managing information exchange during the session and tear-down process upon termination of the session.

26. What is the importance of implementing a Fault Tolerance System? Are there limitations?
    A Fault tolerance system ensures continuous data availability. This is done by eliminating a single point of failure. However, this type of system would not be able to protect data in some cases, such as in accidental deletions.

27. What does 10Base-T mean?
    10 refers to the data transfer rate, in this case is 10Mbps. The word base refers to base band, as oppose to broad band. T means twisted pair, which is the cable used for that network.


28. What is NOS?
   NOS(Network Operating System) is specialized software whose main task is to provide network connectivity to a computer in order for it to be able to communicate with other computer and connected devices.

29. what is DoS?
    DoS (Denial-of-Service attack) is an attempt ot prevent users form being able to access the internet or any other network services. such attacks may come in different forms and are done by a group of perpetrators. one common method of doing this is to overload the system server so it cannot anymore process legitimate traffic and will be forced to reset.

30. what is OSI and what role does it play in computer networks?
    OSI(Open Systems Interconnect) serves as a reference model for data communication. it is made up of 7 layers, with each layer defining a particular aspect on how network devices connect and communicate with one another. one layer may deal with the physical media used, while another layer dictates how data is actually transmitted across the network.