Notes, summaries, assignments, exams, and problems for Computers

Essential Concepts in Information Security

Threat vs. Threat Agent: Key Distinctions

The word “threat” usually stands for a category of things that pose a potential danger. Viruses, worms, and other types of malware, for example, are threats. A “threat agent,” by contrast, is a specific threat, or a specific type of virus, worm, or other malware. For example, the Blaster Worm is a threat agent.

Vulnerability vs. Exposure in Security Systems

Vulnerability is a fault within the system, such as software package flaws, unlocked doors, or an unprotected system port. It leaves things open to an attack or damage.

Exposure is a single instance when a system is open to damage. Vulnerabilities can in turn be the cause of exposure.

Infrastructure Protection

THE WEB:

1. WEB1.0, WEB 2.0, WEB 3.0:

-WEB 1.0 or the read-only web: In the 1990s, information on the Internet was only for reading. It was a network of documents and people could not interact with the content. For example, they couldn’t give their opinions, ask for information or register as users. In addition, the information online was not updated very frequently. Almost everything that people used online was also part of the World Wide Web (www).

WEB 2.0 or the social network:

This was developed during the first decade of the 21st century. In this new web, information became bidirectional. Users could not only receive information, but also create and share it. New services appeared and became popular, such as email, chats, videoconferences,... Continue reading "Evolution of the Web and Information Management" »

Designing Forms and Reports

• Process of designing forms and reports
• General guidelines for formatting forms and reports

Designing Interfaces and Dialogues

• Process of designing interfaces and dialogues
• General guidelines for interface design
• Guidelines for the design of human-computer dialogues

Designing Web and Mobile Interfaces

• General guidelines
• Principles of mobile interface design

Understanding Forms and Reports

What is a Form?

A form is a business document that contains predefined data and may include areas where additional data is to be filled in. Traditionally, forms are paper-based. Today, the layout of almost any paper-based form can be displayed on a video display. Form interaction is a standard method for gathering and displaying information... Continue reading "Effective Interface and Report Design Strategies" »

Boston Housing Data Analysis

library(mlbench)
install.packages("dplyr")
library(dplyr)
library(ggplot2)
library(reshape2)
data("BostonHousing")
housing <- BostonHousing
str(housing)

housing %>%   ggplot(aes(x = medv)) +
  stat_density() +
  labs(x = "Median Value ($1000s)", y = "Density", title = "Density Plot of Median Value House Price in Boston") +
  theme_minimal()

summary(housing$medv)

housing %>%   select(c(crim, rm, age, rad, tax, lstat, medv)) %>%   melt( id.vars = "medv") %>%   ggplot(aes(x = value, y = medv, colour = variable)) +
  geom_point(alpha = 0.7) +
  stat_smooth(aes(colour = "black")) +
  facet_wrap(~variable, scales = "free", ncol = 2) +
  labs(x = "Variable Value", y = "Median House Price ($1000s)") +
  theme_minimal(

Vulnerabilities in Von Neumann Architecture

The system architect of the von Neumann is the way that it can allow direct memory access to the low level languages like C and C++.

If the program goes and tries to access the memory out of bound by allocating code injection to the system, it allows the system to access the memory out of the stack which causes buffer overflow and the attacker can access the other memory from the allocated stack. This way an attacker can get access to the system. Therefore von Neumann architecture is vulnerable to code injection, the effect of the buffer overflow.

Understanding Threats and Attacks

Threats

• It is a potential security violation that might exploit vulnerability of the system or assets.
• Threats can be accidental,

C++ Fundamentals

Let's learn about basic C++

Source: GeeksforGeeks

Loops in C++

For Loop

#include <iostream>
using namespace std;
int main() {
    for(int i = 1; i <= 5; i++) {
        cout << "Good morning \n";
    }
    return 0;
}

While Loop

#include <iostream>
using namespace std;
int main() {
    int i = 0; // Initialization
    while(i < 5) { // Test expression
        cout << "Good morning\n";
        i++; // Update expression
    }
    return 0;
}

Do-While Loop

#include <iostream>
using namespace std;
int main() {
    int i = 2; // Initialization
    do {
        cout << "Good morning\n";
        i++; // Update expression
    } while(i < 1); // Test expression
    return 0;
}

C++ Interview Questions

1.

JavaScript Cheat Sheet

JavaScript Arrays

var cars = ["Mercedes", "Tesla","Volvo"];

• pop(): Removes the last element of an array.
• push(): Adds a new element at the end of an array.
• concat(): Joins various arrays into a single array.
• reverse(): Reverses the order of elements in an array.
• indexOf(): Returns the first index of a given element in an array.
• lastIndexOf(): Returns the last index of a given element in an array.
• join(): Combines elements of an array into a single string.
• sort(): Sorts array elements based on a condition.

Global Functions

These functions are built-in to every browser that runs JavaScript:

• parseFloat(): Parses the argument and returns a floating-point number.
• parseInt(): Parses the argument and returns an integer.
• Number(): Returns a

Pentium P5 Processor Pipelining Stages

The Pentium processor, specifically the Pentium Classic (P5) architecture, featured a five-stage pipeline. The five stages of pipelining in the Pentium processor are as follows:

1. Instruction Fetch (IF): This stage is responsible for fetching instructions from the memory. The instruction pointer determines the next instruction to be fetched, and the instruction cache is utilized to improve performance by storing frequently accessed instructions.
2. Instruction Decode (ID): In this stage, the fetched instruction is decoded. The opcode and operands are identified, and any necessary data dependencies or control hazards are resolved.
3. Execution (EX): The execution stage performs the actual computation or operation specified

Essential Web and Software Terminology

Web Navigation and Structure

• External Hyperlink

  A hyperlink that opens a webpage located on a remote computer. External hyperlinks provide the links that tie the Web together and rely on HTML anchor tags.

• Back Button

  A basic control used across various technologies. In a web browser, a back button allows an end user to navigate to a previously viewed webpage. A back button is also a feature of smartphone software and other consumer-oriented technologies.

• Navigation Structure

  When using navigation requests, for each BSP application, determine the initial page, the navigation methods, and the target pages in a table with navigation paths.

• Refresh

  An act or function of updating the display on a screen.

Web Elements