Operating Systems
Students must be able to explain which resources are managed by an operating system, including temporary and persistent memory, communication with peripherals and networking devices, as well as providing security and user interface, and explain why these resources need to be managed.
An operating system (OS) is a software program that manages the hardware and software resources of a computer. Some of the resources that are managed by an operating system include:
Temporary and persistent memory: An operating system manages the allocation of temporary memory (e.g., random access memory, or RAM) and persistent memory (e.g., hard drive, solid state drive) to ensure that programs and processes have access to the memory they need to function.
Communication with peripherals and networking devices: An operating system manages the communication between the computer and external devices such as printers, scanners, and external hard drives, as well as networking devices such as routers and modems.
Security: An operating system provides security features such as user authentication and file permissions to protect the computer and its data from unauthorized access or tampering.
User interface: An operating system provides a user interface (UI) that allows users to interact with the computer and its programs. The UI typically includes a graphical user interface (GUI) with a desktop, windows, and icons, as well as command-line interfaces and other methods of input and output.
These resources need to be managed by the operating system because they are essential to the proper functioning of the computer. Without proper management, the computer may not be able to effectively allocate and use its resources, may be vulnerable to security threats, and may be difficult for users to interact with.
Students must be able to discuss why management strategies (including Scheduling, Virtual memory, Paging, Interrupts, Buffer, Task division, Polling, Multi-threading and File systems) are used.
There are several management strategies that are used by operating systems to effectively manage the hardware and software resources of a computer. These strategies include:
Scheduling: Scheduling is the process of determining which tasks or processes should be given access to the computer's resources at any given time. This helps to ensure that the computer is used efficiently and that different tasks and processes do not interfere with each other.
Virtual memory: Virtual memory is a feature of an operating system that allows a computer to compensate for shortages of physical memory by temporarily transferring data from RAM to a hard drive or other persistent storage. This allows the computer to run programs that require more memory than is physically available.
Paging: Paging is a memory management technique that allows an operating system to divide physical memory into fixed-size blocks called pages, and then temporarily store inactive pages on a hard drive or other persistent storage. This allows the operating system to allocate physical memory more efficiently.
Interrupts: An interrupt is a signal to the operating system that indicates that an event has occurred that requires the operating system's attention. Interrupts are used to manage events such as input/output operations, system failures, and timer expiration.
Buffers: A buffer is a temporary storage area that is used to hold data while it is being transferred from one location to another. Buffers are used to smooth out the flow of data and help to prevent data loss or corruption.
Task division: Task division is the process of dividing a large task or process into smaller, more manageable parts that can be completed independently. This can help to improve the efficiency and performance of the task or process.
Polling: Polling is a technique in which an operating system periodically checks for the availability of a resource or the occurrence of an event. This can help to ensure that the operating system is aware of changes in the status of the resource or event.
Multi-threading: Multi-threading is the ability of an operating system to execute multiple threads (smaller units of a process) concurrently. This can help to improve the performance and responsiveness of the operating system.
File systems: A file system is a method of organizing and storing files on a computer. Different file systems have different features and capabilities, and an operating system must manage the file system in order to access and manipulate files on the computer.
These management strategies are used to ensure that the operating system can effectively allocate and use the computer's resources, respond to events and requests in a timely manner, and provide a stable and reliable platform for running programs and performing tasks.
Students must be able to explain user authentication and permission handling for all users in a system.
User authentication is the process of verifying the identity of a user who is attempting to access a system. This typically involves the user providing a username and password, and the system checking these credentials against a database of valid users.
Permission handling refers to the process of controlling access to resources within a system. This may involve granting users different levels of access based on their roles or responsibilities, or limiting access to certain resources based on the user's identity.
There are several methods of user authentication that can be used, including:
Password-based authentication: This is the most common method of user authentication, and involves the user providing a username and password to access the system. The system checks the entered credentials against a database of valid users, and if they match, the user is granted access.
Two-factor authentication: This involves adding an additional layer of security to the authentication process by requiring the user to provide a second form of identification in addition to a username and password. This may include a security token, a biometric identifier (e.g., a fingerprint), or a code sent to a mobile phone.
Single sign-on (SSO): SSO is a method of authentication that allows a user to access multiple systems with a single set of login credentials. This can improve the user experience and reduce the risk of password-related security breaches.
Permission handling can be implemented in a number of ways, including:
Access control lists (ACLs): ACLs are lists of permissions that are associated with specific resources within a system. Users are granted or denied access to resources based on their entries in the ACL.
Role-based access control (RBAC): RBAC is a method of permission handling that assigns users to specific roles and grants access to resources based on the role that a user occupies.
Attribute-based access control (ABAC): ABAC is a method of permission handling that grants or denies access to resources based on the attributes of the user and the resource. This can be used to implement more fine-grained access control policies.
Overall, user authentication and permission handling are important for ensuring the security and integrity of a system, and for controlling access to resources within the system.
Students must be able to describe why operating systems have to continually evolve to address security faults, the overall performance of the system and user interface issues.
Operating systems have to continually evolve in order to address a number of issues, including security faults, overall performance, and user interface issues.
Security faults: As cyber threats and security vulnerabilities become more sophisticated, it is important for operating systems to be regularly updated in order to address any security faults that may have been discovered. This helps to protect users and their data from potential security breaches.
Overall performance: Operating systems also need to be updated in order to improve the overall performance of the system. This may involve fixing bugs, optimizing the system for different hardware configurations, or adding new features and functionality.
User interface issues: In addition, operating systems need to be updated to address user interface issues. This may involve improving the usability of the system, adding new features or tools, or updating the look and feel of the user interface.
Overall, operating systems must be continually evolved in order to address a variety of issues and meet the changing needs and expectations of users. This helps to ensure that the system is secure, performs well, and is easy to use.