Operating System Concepts and Mechanisms
Operating System
An operating system (OS) is the program that, after being initially loaded into the computer by a boot program, manages all of the other application programs in a computer. The application programs make use of the operating system by making requests for services through a defined application program interface (API). In addition, users can interact directly with the operating system through a user interface, such as a command-line interface (CLI) or a graphical UI (GUI). The operating
Read MoreHalftone Shading, Ambient Light, and Other Computer Graphics Concepts
Halftone Shading, Ambient Light, and Other Computer Graphics Concepts
Halftone shading is a rendering technique used to simulate continuous-tone images, such as grayscale, using patterns of dots or lines in black and white. This method is commonly used in printing and graphic design to create the illusion of different shades of gray or colors with limited resources.
In the context of computer graphics, halftone shading involves creating shading effects by varying the density and size of dots or patterns
Read MoreCybersecurity Essentials: Attacks, Cryptography, and Security
What is an Active Attack in Security?
In cybersecurity, an active attack is a type of network attack where the attacker actively interacts with the target system to disrupt, modify, or steal information. Active attacks are often aimed at gaining unauthorized access, manipulating data, or compromising system integrity.
Types of Active Attacks
- Masquerade Attack: The attacker pretends to be an authorized user by stealing or forging credentials, allowing unauthorized access to sensitive data.
- Replay Attack:
Regular Languages, Expressions, and Automata
Item 2 – Regular Languages
2.1 – Languages on Literacy
Consider the alphabet = {a, b}. For all natural numbers n, there are only a finite number of words whose length is n. These strings can be ordered lexicographically, numbered 0, 1, 2… For example, for length 1: 0 is a, 1 is b. For length 2: 0 is aa, 1 is ab, and so on. So, assuming an arbitrary alphabet Q, since all alphabets are finite, we can assign an arbitrary order to the characters. Without loss of generality, we can write Q = {a0, a1,
Read MoreSemantics, Typing, and Paradigms in Programming Languages
Operational Semantics
Describes the meaning of a program in terms of its execution on an abstract machine or step-by-step behavior. It is concerned with how a program executes (correctness).
Denotational Semantics
Maps programs to mathematical objects (functions, sets, etc.) to describe their meaning. It focuses on what a program computes, abstracting away how it executes.
Axiomatic Semantics
Specifies the behavior of programs using logical assertions (preconditions and postconditions). It is used to
Read MoreOperating Systems: Core Concepts and Mechanisms
Distributed and Parallel Operating Systems
Distributed Operating Systems:
- Manages a group of independent computers and makes them appear as a single system to the user.
- Focuses on resource sharing, fault tolerance, and transparency.
- Examples: Network OS, Cloud OS.
Parallel Operating Systems:
- Manages multiple processors in a single system to perform tasks simultaneously.
- Aims to enhance computation speed and resource utilization.
- Examples: Symmetric Multiprocessing (SMP), Cluster systems.