Operating System
Unit 4 Assignment
WEEK 3 ASSIGNMENT OPERATING SYSTEM
1.What is a File system ? Explain the Linux file system with a diagram ?
Answer:
A file system is a way of organizing and storing data on a storage device such as a hard drive or a solid-state drive. It provides a structure for organizing files and directories and enables users to create, modify, and delete files and directories.
The Linux file system is a hierarchical file system that organizes files and directories in a tree-like structure. The root directory is the top-level directory of the file system, and all other directories and files are located within it. The Linux file system follows a standard directory structure known as the Filesystem Hierarchy Standard (FHS), which specifies the layout and naming conventions for directories and files.
The diagram below shows the Linux file system hierarchy:
The root directory (/) is at the top of the hierarchy and contains all other directories and files. The bin directory contains executable files (i.e., programs or commands) that can be run by users or the system. The dev directory contains device files that represent hardware devices such as hard drives, USB drives, or printers.
The etc directory contains configuration files for the system and applications installed on it. The var directory contains files that change frequently, such as log files or temporary files. The lib directory contains libraries (i.e., code used by applications) that are shared between programs.
Finally, the log directory contains log files that record system events and messages. By following this standard directory structure, the Linux file system provides a consistent and organized way to store and access files and directories.
2.Explain the dual modes of an Operating system ?
Answer:
The dual mode of an Operating System refers to the existence of two different modes in which an Operating System operates. These two modes are:
- User Mode: In user mode, the CPU executes the code that belongs to a user program, and it has limited access to system resources. In this mode, a user program cannot directly access hardware resources or memory, and it can only execute instructions that are non-privileged.
- Kernel Mode: In kernel mode, the CPU executes the code that belongs to the operating system, and it has complete access to all system resources. In this mode, the operating system can access hardware resources, memory, and other system resources, and it can execute privileged instructions.
The dual mode architecture of the Operating System is designed to provide security and protection to the system. User mode is designed to protect user programs from accessing system resources that could cause harm or instability. In contrast, kernel mode is designed to allow the operating system to manage hardware resources and provide system services. This separation ensures that user programs cannot interfere with the operation of the system, and it provides a layer of protection against malicious programs.
The dual mode architecture is implemented using hardware features such as a memory management unit (MMU) and privileged instructions. The MMU provides memory protection by creating virtual memory spaces for each process, and it maps virtual addresses to physical addresses. The privileged instructions are instructions that can only be executed in kernel mode, and they provide access to hardware resources that are not accessible in user mode.
Overall, the dual mode architecture is an essential feature of modern operating systems, and it plays a critical role in ensuring the stability and security of the system.
3.What are system program ? Highlight few characteristics of it.
Answer:
System programs are software programs that are designed to manage and control the operation of a computer system. They are a type of application software that provides essential services and functions to the operating system, other system software, and user applications.
Some common examples of system programs include device drivers, utility programs, file management tools, and system libraries.
Here are a few characteristics of system programs:
- They run in kernel mode: System programs require privileged access to hardware and system resources, so they run in kernel mode. This allows them to perform low-level functions such as managing system memory, controlling hardware devices, and interacting with the operating system kernel.
- They provide essential services: System programs provide essential services to the operating system and other system software. For example, device drivers allow the operating system to interact with hardware devices such as printers, keyboards, and mice. Utility programs provide tools for system maintenance and troubleshooting.
- They are written in low-level languages: System programs are often written in low-level programming languages such as C and assembly language. This is because they need to interact closely with the hardware and operating system, and these languages provide direct access to system resources.
- They are typically not visible to users: System programs are typically not visible to users, and they run in the background without user interaction. This is because their functions are essential to the operation of the system, but they do not provide a direct benefit to the user.
Overall, system programs play a critical role in managing and controlling the operation of a computer system, and they are essential for the proper functioning of the system.
4.How are server systems classified? What is asymmetric clustering?
Answer:
Server systems can be classified based on different criteria, such as their hardware architecture, operating system, purpose, or functionality. Here are some common ways of classifying server systems:
- Based on hardware architecture: Servers can be classified based on their hardware architecture, such as single-processor or multi-processor systems, blade servers, rack-mounted servers, or mainframe systems.
- Based on operating system: Servers can be classified based on the operating system they run, such as Windows Server, Linux server, or macOS server.
- Based on purpose: Servers can be classified based on their intended purpose, such as file servers, web servers, email servers, database servers, or application servers.
- Based on functionality: Servers can also be classified based on their functionality, such as load balancers, firewalls, proxy servers, or DNS servers.
Asymmetric clustering is a type of clustering technique in which each server in the cluster performs a different role or function. In asymmetric clustering, there is a primary node that manages the cluster resources, and one or more secondary nodes that perform specific tasks or provide specialized services. The secondary nodes are typically designed to complement the primary node by providing additional functionality or redundancy.
Asymmetric clustering is often used in high-availability environments where continuous uptime is critical. For example, in a web server cluster, the primary node might handle the incoming web requests and distribute them to the secondary nodes, which might handle database queries or content delivery. This way, the workload is distributed across multiple servers, and the system can continue to operate even if one node fails or is taken offline for maintenance.