In Ubuntu Linux

  •  The time interval between the submission of a process and its completion is known as "Process Turnaround Time."
  • The time for which a process waits in the ready queue until it starts execution is known as "Waiting Time" or "Wait Time."
  • Process Response Time is the duration between the submission of a process and the initiation of its execution.
  • The full form of FCFS is "First Come, First Served." It's a scheduling algorithm used in computer science and operating systems, where processes are executed based on their arrival time. The process that arrives first is executed first, followed by the next one in the order of arrival.
  • In memory management, PMT stands for "Page Map Table"
  • MMU: Memory Management Unit
  • TLB: Translation Lookaside Buffer
  • List out basic types of files in unix :
    • Regular Files
    • Directories
    • Symbolic Links (symlinks)
    • Device Files (Character and Block)
    • FIFOs (Named Pipes)
    • Sockets
  • In Unix, there are three types of permissions, commonly abbreviated as:
    • Read (r)
    • Write (w)
    • Execute (x)

  • In Unix, there are several tools available for mathematical calculations. Some commonly used ones include:

    1. bc: Basic Calculator
    2. expr: Expression evaluator
    3. awk: Powerful text processing tool that can also perform mathematical operations
    4. Perl: General-purpose scripting language with strong support for mathematical calculations
    5. Python: General-purpose programming language with extensive mathematical libraries

    These tools allow users to perform various mathematical calculations directly from the command line or within scripts.

  • In Unix, "pwd" stands for "Print Working Directory." It's a command used to display the current working directory in the terminal.

  • In shell programming, there are mainly two types of variables:

    1. Scalar Variables: Hold a single value.

    2. Array Variables: Hold multiple values.

    Scalar variables hold a single value such as strings or numbers, while array variables can hold multiple values accessed by index (indexed arrays) or keys (associative arrays).

  • In Unix shell programming, "IFS" stands for "Internal Field Separator." It's a special variable that determines how the shell recognizes word boundaries or field separations when processing strings. The default value of IFS is whitespace characters (space, tab, newline), but it can be customized by the user to specify different delimiters for field splitting.
  • In Unix shell programming, "GPL" typically stands for the "GNU Public License." It's a widely used free software license that guarantees users the freedom to use, study, modify, and distribute software.
  • In Unix, "CUI" stands for "Command-Line User Interface"
  • In Unix shell programming, "CUI" typically stands for "Character User Interface"
  • In Unix, "CDE" stands for "Common Desktop Environment" It is a desktop environment for Unix systems that provides a graphical user interface (GUI) for users to interact with the operating system and its applications. CDE was developed in the 1990s and aimed to provide a consistent user experience across various Unix platforms.
  • In Unix, "KDE" stands for "K Desktop Environment" It's a popular desktop environment for Unix-like operating systems, providing a graphical user interface (GUI) for users to interact with the system and its applications. KDE offers a range of features and customization options to enhance the user experience.

  • In the KDE desktop environment on Unix systems, the start menu items include:

    1. Applications: Access to installed applications and utilities.
    2. Computer: Provides shortcuts to various system directories and settings.
    3. Favorites: Allows users to customize a list of frequently used applications or directories.
    4. Leave: Options for shutting down, restarting, or logging out of the system.
    5. Recent Documents: Quick access to recently opened files.
    6. Help: Documentation and user manuals for KDE and installed applications.
    7. Run Command: Opens a dialog to execute commands directly.
    8. Lock Session: Locks the current session to secure the desktop.
    9. Switch User: Allows switching between user accounts.
    10. Logout: Logs out the current user session.

    These menu items provide users with easy access to applications, system settings, and various other functionalities within the KDE desktop environment.

  • In Unix, "APT" stands for "Advanced Package Tool" It is a package management system used primarily in Debian-based Linux distributions, such as Debian itself, Ubuntu, and others. APT enables users to install, upgrade, and manage software packages on their Unix systems, including handling dependencies and repositories effectively.

  • here are the shortened steps for creating and renaming a folder in Ubuntu:

    • Creating a Folder:
      • Open a terminal (Ctrl + Alt + T).
      • Type mkdir FolderName and press Enter.
    • Renaming a Folder:
      • Open a terminal (Ctrl + Alt + T).
      • Type mv OldFolderName NewFolderName and press Enter.
  • Alternatively, you can use the graphical file manager (Nautilus):
    • To create a folder: Right-click in the desired location, select "New Folder," and enter the folder name.
    • To rename a folder: Right-click on the folder, select "Rename," and enter the new name.
  • In Ubuntu, as well as in general computing, "FQDN" stands for "Fully Qualified Domain Name." It refers to the complete domain name for a specific host, including its top-level domain (TLD). An example of a FQDN is "www.example.com", where "www" is the host or subdomain, "example" is the second-level domain, and ".com" is the top-level domain. FQDNs are used to uniquely identify hosts on the internet.
  • In Ubuntu, "UFW" stands for "Uncomplicated Firewall." It is a user-friendly command-line utility used to manage netfilter firewall rules. UFW simplifies the process of configuring and managing firewall settings on Ubuntu systems by providing a straightforward syntax and easy-to-use interface.
  • In Ubuntu or in the context of computing in general, "DIT" typically stands for "Directory Information Tree." This term is commonly used in the context of LDAP (Lightweight Directory Access Protocol), referring to the hierarchical structure of directory information stored within an LDAP directory server.
  • In Ubuntu, as well as in general computing, "SAMBA" stands for "Server Message Block." It is an open-source software suite that provides file and print services interoperability between Unix-like systems, including Linux and Ubuntu, and Windows-based systems. SAMBA allows Ubuntu systems to act as file servers or print servers for Windows clients by implementing the SMB/CIFS networking protocol.
  • In Ubuntu, as well as in general computing, "CIFS" stands for "Common Internet File System." It is a network file system protocol that provides a way for clients to access files and resources over a network. CIFS is an enhanced version of the Server Message Block (SMB) protocol and is commonly used for sharing files and printers between Unix-like systems, such as Ubuntu, and Windows-based systems.
  • In Ubuntu, as well as in general computing, "SMB" stands for "Server Message Block." It is a network communication protocol used for providing shared access to files, printers, and other resources between devices on a network, particularly in Windows environments. SMB is the underlying protocol used by SAMBA for interoperability between Unix-like systems, such as Ubuntu, and Windows-based systems.
  • In Ubuntu, "WINE" stands for "WINE Is Not an Emulator." WINE is a compatibility layer that allows users to run Windows applications on Unix-like operating systems, including Ubuntu, without needing to emulate a full Windows environment. Instead of emulating Windows, WINE translates Windows API calls into native Unix-like system calls, enabling Windows applications to run directly on the Unix-like system.
  • The memory allocated from secondary storage is typically referred to as "Virtual Memory". It's a memory management technique used by operating systems to extend the available memory beyond the physical RAM by temporarily transferring data to and from secondary storage devices such as hard drives or SSDs. This allows the system to run more applications concurrently without running out of physical memory.

  • The scheduling algorithm that automatically executes the process in the queue at the end of a quantum is called Round Robin scheduling.

    In Round Robin scheduling, each process is assigned a fixed time interval, known as a quantum or time slice. The scheduler executes each process for its quantum, and if the process does not complete within that time, it is preempted and moved to the back of the ready queue. The scheduler then selects the next process in the queue to execute, and the cycle continues. This way, Round Robin ensures fairness among processes and prevents any single process from monopolizing the CPU for an extended period.

  • When a process is halted due to an I/O interruption, it is commonly referred to as "Blocked" or "Waiting".

    In the context of process scheduling, this state is also known as "Blocked" or "Waiting for I/O." When a process initiates an I/O operation, such as reading from or writing to a file or interacting with a device like a keyboard or a network interface, it must wait until the operation completes before it can proceed. During this time, the process is said to be blocked or waiting for the I/O operation to finish. Once the I/O operation is completed, the process can resume execution.

  • The Bourne Shell, often abbreviated as "sh", was invented by Stephen Bourne, a computer scientist who worked at Bell Labs. Stephen Bourne created the Bourne Shell in the late 1970s as a replacement for the Thompson shell (sh) in Unix Version 7. The Bourne Shell became one of the foundational components of Unix-like operating systems and served as the basis for subsequent shell implementations and scripting languages.

  • Storing data in a specific format on magnetic media is commonly referred to as "Formatting."

    Formatting involves organizing the magnetic media (such as hard drives, floppy disks, or magnetic tapes) into logical structures that can be accessed and managed by a computer system. This process typically involves creating tracks, sectors, and filesystem structures on the magnetic media to facilitate efficient data storage and retrieval.

    There are different types of formatting, including low-level formatting, which prepares the physical media for use, and high-level formatting, which creates filesystem structures and allocates space for storing files.

  • The whoami command displays the username of the current user who executed the command.

  • The command that changes the mode (permissions) of a file in Unix-like operating systems is chmod.

  • The command used to print text in the shell is echo.

  • The software with source code that anyone can modify and enhance is called "Open-source software".

  • In Ubuntu, as well as in general computing, "GUI" stands for "Graphical User Interface." It refers to a visual way of interacting with a computer using graphical elements such as windows, icons, buttons, and menus, rather than solely relying on text-based commands. GUIs provide a more intuitive and user-friendly environment for users to perform tasks and interact with software applications.

  • The variable that typically stores the absolute pathname of the user's mailbox in Unix-like systems, including Ubuntu, is $MAIL.

  • To copy a file named "abc.txt" to a folder named "sybca" in Ubuntu, you can use the cp command followed by the source file and the destination directory. Here's the command:

    • cp abc.txt sybca/
    • This command will copy the file "abc.txt" to the "sybca" folder in the current directory.
    • If the "sybca" folder is located in a different directory, you would need to specify the absolute or relative path to that directory instead of just "sybca/". For example:
    • cp abc.txt /path/to/sybca/
    • Replace "/path/to/sybca/" with the actual path to the "sybca" folder.
  • In Linux systems, particularly those using the X Window System (X11), the configuration file responsible for configuring graphics settings is usually /etc/X11/xorg.conf or /etc/X11/xorg.conf.d/. These files contain configuration directives that specify settings such as display resolution, refresh rates, graphics drivers, and other parameters related to the graphics hardware and display configuration. However, modern Linux distributions often auto-detect and configure graphics settings without the need for manual intervention in these files.
  • To add a new user in Ubuntu, you can use the adduser command. Here's the syntax:
    • sudo adduser username
    • Replace "username" with the desired username for the new user. When you run this command, you'll be prompted to set a password and provide additional information for the new user, such as their full name, phone number, etc. You can press Enter to skip optional information. Once you've completed the prompts, the new user will be created on your Ubuntu system.

  • In Ubuntu, as well as in many other Linux distributions, the service used to resolve hostnames to IP addresses and vice versa is called the "Domain Name System" (DNS).

    The DNS service resolves human-readable domain names (such as example.com) to their corresponding IP addresses (such as 192.0.2.1) and vice versa. This translation process is crucial for internet communication, as it allows devices to locate each other on the network using domain names instead of IP addresses.

  • The service used for directory services authentication in Ubuntu and many other Unix-like operating systems is called "LDAP" (Lightweight Directory Access Protocol).

    LDAP is a protocol used for accessing and maintaining distributed directory information services over a network. It provides a centralized directory of user accounts, groups, and other resources, allowing systems to authenticate users and manage access to network resources. LDAP is commonly used in enterprise environments for centralized authentication and authorization.