Q1 : Why we use LINUX?
A : LINUX is used widely because it is completely different from other operating systems where every aspect comes with something extra i.e. some additional features. Some of the major reasons to use LINUX are listed below
- It is an open source operating system where programmers get the advantage of designing their own custom OS
- Software and the server licensing required to install Linux is completely free and can be installed on many computers as required
- It has low or minimum but controllable issues with viruses, malware, etc
- It is highly secured and supports multiple file systems
Q2 : What is the difference between UNIX and LINUX?
A : 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 non-propriety operating system for the masses.
Q3 : How secured is Linux? Explain.
A : Security is the most important aspect of an operating system. Due to its unique authentication module, Linux is considered as more secured than other operating systems. Linux consists of PAM. PAM is Pluggable Authentication Modules. It provides a layer between applications and the actual authentication mechanism. It is a library of loadable modules which are called by the application for authentication. It also allows the administrator to control when a user can log in. All PAM applications are configured in the directory “/etc/pam.d” or in a file “/etc/pam.conf”. PAM is controlled using the configuration file or the configuration directory.
A : Below are the list of modes used in Network Bonding :</div
- balance-rr or 0 – round-robin mode for fault tolerance and load balancing.
- active-backup or 1 – Sets the active-backup mode for fault tolerance.
- balance-xor or 2 – Sets an XOR (exclusive-or) mode for fault tolerance and load balancing.
- broadcast or 3 – Sets a broadcast mode for fault tolerance. All transmissions are sent on all slave interfaces.
- 802.3ad or 4 – Sets an IEEE 802.3ad dynamic link aggregation mode. Creates aggregation groups that share the same speed & duplex settings.
- balance-tlb or 5 – Sets a Transmit Load Balancing (TLB) mode for fault tolerance & load balancing.
- balance-alb or 6 – Sets an Active Load Balancing (ALB) mode for fault tolerance & load balancing.
Q5 : Which account is created on Linux installation?
A : With the installation of Linux, a superuser account is created called as ‘root’.
Q6 : What are the basic components of Linux?
A : Just like any other typical operating system, Linux has all of these components: kernel, shells and GUIs, system utilities, and an 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.
Q7 : Enlist the features of Linux operating system?
A : Following are some important features of LINUX operating system
- Linux kernel and application programs can be installed on any kind of hardware platform and thus is considered portable.
- It serves the purpose of multitasking by serving various functions simultaneously.
- It provides security services in three ways namely, Authentication, Authorization, and Encryption.
- It supports multiple users to access the same system resource but by using different terminals for operation.
- Linux provides a hierarchical file system and its code is freely available to all.
- It has its own application support (to download and install applications) and customized keyboards.
- Linux distros provide live CD/USB to their users for installation.
Q8 : What is the advantage of open source?
A : Open source allows you 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.
Q9 : What are Linux file systems?
A : By default, Linux supports and use ext3 or ext4 file systems. UNIX supports file systems like jfs, gpfs (AIX), jfs, gpfs (HP-UX), jfs, gpfs (Solaris).
Q10 : What are the Linux Distribution (Operating System) Names?
A : Here are the some Linux operating system names:
- Redhat Enterprise Linux
- Fedora Linux
- Debian Linux
- Suse Enterprise Linux
- Ubuntu Linux
First, entries in the shadowed file which don’t exist in the main file are removed. Then, shadowed entries which don’t have `x’ as the password in the main file are updated. Any missing shadowed entries are added. Finally, passwords in the main file are replaced with `x’. These programs can be used for initial conversion as well to update the shadowed file if the main file is edited by hand.
A : LILO (Linux Loader) is the boot loader for Linux operating system to load it into the main memory so that it can begin its operations. Bootloader here is a small program that manages a dual boot. LILO resides in MBR (Master Boot Record).
Its major advantage is that it allows the fast boot up of Linux when installing in the MBR.
Its limitation lies in the fact that it is not possible for all computers to tolerate modification of MBR.
A : The syslogd daemon tracks the system information and saves it to specified log files.
A : When you select only a portion of your file hierarchy or a single partition to back up, it is called partial backup
Q16 : What is the minimum number of partitions that you need to install Linux?
A : Minimum 2 partitions are needed for installing Linux. The one is “/ or root” which contains all the files and the other is swap. Linux file system is function specific which means that files and folders are organized according to their functionality. For example, all executables are in one folder, all devices in another, all libraries in another and so on. “/ or root” is the base of this file system. All the other folders are under this one. “/” can be considered as “C:”. Swap is a partition that will be used as virtual memory. If there is no more available RAM a Linux computer will use an area of the hard disk, called swap, to temporarily store data. In other words, it is a way of expanding your computers RAM.
A : Both Linux and UNIX share many common applications such as:
- GUI, file, and windows managers (KDE, Gnome)
- Shells (ksh, csh, bash)
- Various office applications such as OpenOffice.org
- Development tools like perl, php, python, GNU c/c++ compilers
- Posix interface
A : In Linux, curl command is used to test an application’s endpoint or connectivity to an upstream service endpoint. curl command will be used to determine if the application can reach another service, like a database, or checking if your service is healthy.
curl Example:
$ curl -I -s myapplication:5000
HTTP/1.0 500 INTERNAL SERVER ERROR
This example through an exception saying that your application can’t reach your server.
In the above command, the -I option shows the header information and the -s option silences the response body.
A : Some of the most used UNIX operating systems are:
- HP-UX
- IBM AIX
- Sun Solairs
- Mac OS X
- IRIX
Q22: What are System Startup Scripts?
A : By default, Linux and UNIX come with system initialization script but they are located in different directories:
- HP-UX – /sbin/init.d
- AIX – /etc/rc.d/init.d
- Linux – /etc/init.d
Q23 : What is Swap space?
A : Swap space is the amount of physical memory that is allocated for use by Linux to hold some concurrent running programs temporarily. This condition usually occurs when Ram does not have enough memory to support all concurrent running programs. This memory management involves the swapping of memory to and from physical storage.
There are different commands and tools available to manage the Swap space usage.
Q24 : Explain virtual desktop?
A : When there are multiple windows available on the current desktop and there appears the problem of minimizing and maximizing windows or restoring all the current programs, there ‘Virtual Desktop’ serves as an alternative. It allows you to open one or more programs on a clean slate. Virtual desktops are basically stored on a remote server and serve the following benefits:
Virtual desktops are basically stored on a remote server and serve the following benefits
- Cost savings as the resources can be shared and allocated as and when required.
- Resources and energy are more efficiently used.
- Data integrity is improved.
- Centralized administration
- Less compatibility issues.
Q25 : Does it help for a Linux system to have multiple desktop environments installed?
A : In general, one desktop environment, like KDE or Gnome, is good enough to operate without issues. It’s all a matter of preference for the user, although the system allows switching from one environment to another. Some programs will work in one environment and not work on the other, so it could also be considered a factor in selecting which environment to use.