Computer Science Computer Fundamentals

An operating system (OS) is a software that manages computer hardware and software resources and provides common services for computer programs. Its main functions include:

• Managing hardware resources (CPU, memory, I/O devices).
• Providing a user interface.
• Facilitating program execution.
• Managing files and directories.
• Ensuring security and access control.

• Process: An independent program in execution, with its own memory space and resources.
• Thread: The smallest unit of a process that can be scheduled for execution. Threads within the same process share the same memory space.

Virtual memory is a memory management technique that provides an "idealized abstraction of the storage resources" that are actually available on a given machine. It creates an illusion of a very large memory by using both hardware and software to enable a computer to compensate for physical memory shortages, temporarily transferring data from RAM to disk storage

• TCP (Transmission Control Protocol): A connection-oriented protocol that ensures reliable and ordered delivery of a stream of bytes from one program to another.
• UDP (User Datagram Protocol): A connectionless protocol that allows sending messages without establishing a connection, providing lower latency but with no guarantee of delivery, order, or error-checking.

• Stack Memory: A region of memory used for static memory allocation, such as local variables and function call management. It is fast and automatically managed by the CPU.
• Heap Memory: A region used for dynamic memory allocation, where blocks of memory are allocated and freed in an arbitrary order. It is managed by the programmer and typically slower due to the overhead of managing memory allocations.

A database index is a data structure that improves the speed of data retrieval operations on a database table at the cost of additional space and write time. It is used to quickly locate and access the data in a database without having to search every row in a table each time a database table is accessed.

Normalization is a process in database design that organizes data to minimize redundancy and improve data integrity. The purpose is to:

• Reduce data redundancy.
• Ensure data dependencies make sense (only storing related data in a table).
• Improve data integrity and consistency.

A deadlock is a situation in an operating system where two or more processes are unable to proceed because each is waiting for the other to release a resource. It can be avoided by:

• Implementing a deadlock avoidance algorithm like Banker's algorithm.
• Ensuring that at least one of the necessary conditions for deadlock (mutual exclusion, hold and wait, no preemption, circular wait) cannot hold.

The OSI (Open Systems Interconnection) model is a conceptual framework used to understand and implement interoperable network protocols in seven layers. Its purpose is to standardize the functions of a telecommunication or computing system without regard to its underlying internal structure and technology, facilitating interoperability between different products and software.

Polymorphism is an OOP concept that allows objects of different classes to be treated as objects of a common superclass. It enables a single function or method to operate in different ways depending on the context, typically achieved through method overriding (runtime polymorphism) and method overloading (compile-time polymorphism).