Bcs 011 Solved Free Assignment 2024-25 Sem 1 Part 3

Question 2:  (7×4=28 Marks) 

(a) Why do you need virus detection software? What are their drawbacks? What are the techniques to identify a virus? List any 4 latest for desktop systems.

 Ans : Why Do You Need Virus Detection Software? 

Virus detection software, often called antivirus software, is essential for several reasons: 

1. Protection Against Malware: Antivirus software protects systems from a variety of malware, including viruses, trojans, worms, ransomware, and spyware, which can steal, damage, or delete data. 

2. Data and Identity Security: It helps safeguard sensitive information, including personal, financial, and business data, from being stolen by cybercriminals. 

3. Prevention of System Damage: Malware can corrupt files, slow down system performance, or even crash systems entirely. Antivirus software detects and removes these threats before they can cause harm. 

4. Protection from Phishing Attacks: Many antivirus programs also offer features that prevent phishing attempts by blocking malicious links and identifying fake websites. 

5. Real-Time Threat Detection: Continuous monitoring and real-time scanning of files and emails help prevent infections before they spread.

Drawbacks of Virus Detection Software 

System Performance Impact: Antivirus software can consume significant system resources, which can slow down the computer, especially during scans or updates. 

7. False Positives: Sometimes, antivirus programs incorrectly identify safe programs as threats, which can disrupt legitimate activities. 

8. Incomplete Protection: No antivirus software can guarantee 100% protection, especially against new or sophisticated malware. Some advanced threats might bypass detection. 

9. Cost: Many antivirus programs require a subscription fee for full protection, which might be an extra expense for users. 

10. User Dependence: Some users may become overly reliant on antivirus software and neglect other important security practices, such as updating their systems or being cautious online. 

Techniques to Identify a Virus 

Signature-Based Detection: This method identifies known viruses by comparing the code of a file with a database of virus signatures. It is effective against known threats but not against new, unknown viruses. 

12. Heuristic Analysis: This technique analyzes the behavior of a file or program to identify suspicious activities that could indicate a virus, such as modifying system files or creating unauthorized network connections. 

13. Behavior-Based Detection: It monitors the behavior of programs in real-time. If a program performs actions typical of malware, such as replicating itself or encrypting files, it is flagged as a potential virus. 

14. Sandboxing: Suspect programs are run in a virtual, isolated environment where their behavior can be observed without risking harm to the actual system. If the program behaves maliciously, it is identified as a threat. 

Four Latest Viruses for Desktop Systems (as of recent times) 

15. Raspberry Robin: A worm spread through USB drives, potentially linked to various forms of ransomware. 

16. Emotet (2024 variants): A modular banking trojan known for spreading through malicious email attachments and links, capable of delivering other malware. 

17. BlackCat (ALPHV): A highly sophisticated ransomware variant targeting enterprise networks, demanding ransom payments in cryptocurrency. 

18. QBot (aka QakBot): A financial malware and banking trojan that spreads via phishing emails, often used to install other malware or ransomware. 

(b) Consider that you have to run several computer programs simultaneously on a computer. Each program takes input from a file and output information on a printer. How does different components of an Operating system (like memory management, I/O management, Process management, file system and user interface) will help in execution of these programs. 

Ans: When running multiple computer programs simultaneously, the Operating System (OS) plays a critical role in managing resources to ensure smooth and efficient execution. Various components of the OS help in managing these tasks, including memory management, I/O management, process management, file system, and the user interface. Here’s how each of these components supports running multiple programs: 

1. Memory Management 

Memory management in an OS is responsible for allocating and deallocating memory to the programs running on the system. Multiple programs require different portions of memory to store their instructions and data. The memory management component ensures: 

• Memory Allocation: Each program is given its own space in RAM (Random Access Memory) to avoid conflicts. 

• Multitasking Support: Using techniques like paging or segmentation, the OS efficiently switches between programs, giving the illusion that they are all running simultaneously. 

• Virtual Memory: If the physical memory is insufficient, the OS uses virtual memory, extending memory to the hard disk and allowing more programs to run concurrently. 

• Memory Protection: Ensures that one program cannot access or modify the memory allocated to another, protecting the integrity of each process. 

2. I/O Management 

Input/Output (I/O) management deals with handling communication between programs and the various I/O devices such as printers, keyboards, and storage devices. When multiple programs need to interact with these devices, the OS ensures: 

• Scheduling of I/O Requests: The OS uses I/O scheduling algorithms to decide the order in which programs access devices like the printer. 

• Buffering: The OS uses buffers to store data temporarily while waiting for the printer to become available. This allows programs to continue running without being delayed by slow I/O operations. 

• Device Drivers: The OS uses device drivers to communicate with hardware devices. It abstracts the complexity of hardware interactions, making it easier for programs to perform I/O tasks. 

3. Process Management 

Process management is responsible for creating, scheduling, and terminating processes (programs in execution). When running several programs simultaneously, the OS ensures that each program runs smoothly and fairly by: 

• Process Scheduling: The OS uses a scheduler to manage the execution of multiple programs. It divides CPU time among all the running processes using scheduling algorithms (e.g., Round Robin, Priority Scheduling) to ensure that each program gets a fair share of processing time. 

• Context Switching: When switching between programs, the OS performs context switching, saving the state of the current program and loading the state of the next program, ensuring smooth multitasking. 

• Process Synchronization: If programs need to interact or share data, the OS manages synchronization mechanisms (e.g., semaphores, locks) to avoid conflicts and ensure proper coordination between processes. 

• Inter-Process Communication (IPC): The OS provides IPC mechanisms like message passing or shared memory so that programs can communicate and share data efficiently. 

4. File System 

The file system component of the OS handles the organization, storage, retrieval, and management of files on storage devices (e.g., hard drives, SSDs). Each program may need to access input files or create output files, and the OS facilitates this by: 

• File Access Management: The OS allows programs to read from and write to files stored on the disk. It ensures that multiple programs can safely access files without interfering with each other using file locks or access control. 

• File Permissions: The OS manages who can read, write, or execute certain files, ensuring the right programs have appropriate permissions to access the required data. 

• File Organization: The OS organizes files in a hierarchical structure (using directories) to make it easier for programs to locate and access the files they need. 

5. User Interface (UI) 

The user interface allows users to interact with the OS and the programs running on it. There are two main types of UIs: Graphical User Interface (GUI) and Command Line Interface (CLI). The UI helps in: 

• Program Execution: Users can launch and manage multiple programs either through a GUI (e.g., clicking on icons) or a CLI (e.g., running commands in a terminal). 

• Monitoring Processes: The user interface (via Task Manager in GUI or system commands in CLI) allows users to monitor the status of programs, CPU usage, memory consumption, and I/O activity. 

• Interaction with Files: Through the UI, users can manage files needed by the programs (e.g., copying, moving, or deleting files) and view file structures. 

 

Summary of OS Components’ Roles in Executing Multiple Programs 

Component	Role in Program Execution
Memory Management	Allocates memory for each program, enables multitasking, and uses virtual memory if needed.
I/O Management	Manages communication with input/output devices like printers, ensures efficient scheduling.
Process Management	Handles process creation, scheduling, and coordination, ensuring CPU time distribution.
File System	Organizes and manages file access for program inputs/outputs.
User Interface	Provides a way for users to launch and monitor multiple programs simultaneously.