Big Idea 4: Computer Systems and Networks (copy)

The Internet

• Internet: is a network of networks.

  • The word Internet came from “interconnection of computer networks.”

• The Internet is hardware-driven with wires, cables, and devices such as routers and servers.

• Routers are computing devices along a path that send information to the next stop on the path.

• Routing: is the process of finding a path from sender to receiver

• Bandwidth: is a measure of the maximum amount of data that can be transferred through a channel or network connection.

  • It's measured in bits per second, and it determines how quickly you can download and upload files from the internet.

• Internet protocol (IP): is responsible for addressing and routing your online requests.

• Transmission control protocol (TCP): is a protocol that defines how computers send packets of data to each other.

• User datagram protocol (UDP): is a protocol that allows computer applications to send messages without checking for missing packets to save on time needed to retransmit missing packets.

Scalability

• Scalability: is the ability of a system, network, or process to handle a growing amount of work efficiently.

• It can also be defined as the capacity to increase services and products quickly with minimal interruption and cost.

  • This is especially important in software engineering, where scalability is crucial when developing applications that are expected to handle large amounts of traffic or data.

• Minimizing HTTP requests can reduce load time

Fault Tolerance

Hardware Failure

• Hardware failure: is when a hardware device, such as a computer or printer, stops working properly due to an issue with the physical components.

• The cause of the failure can be anything from electrical wiring issues to incorrect installation and configuration of hardware components.

• In any case, diagnosing and repairing hardware failures can be difficult without proper tools and experience in dealing with this type of issue.

Operational Failures

• Operational failures: are any issues or breakdowns in the operation of a business, machine, system, process, etc.

• They can range from unexpected downtime to incorrect results due to faulty programming.

• Operational failures can have significant impacts on profitability and reputation if not addressed swiftly and appropriately.

Weather

• The internet has cables and wires spanning the world that connect computers.

• Natural disasters: could cause the hardware to be destroyed, bringing the network activity to a halt.

• Solar Flare: is an intense radiation that is released from the sun.

  • This happens because of the release from the sun.

Cyberattacks

• Cyberattacks: are malicious attempts to damage or disrupt computer systems, networks, and data.

• They can be carried out by individuals, groups, or organizations with malicious intent.

• Cyberattacks typically involve the use of malware such as viruses and ransomware that allow attackers to gain access to a system for a variety of nefarious purposes including stealing data and financial information or launching denial-of-service attacks.

• Some cyberattack methods used today include phishing campaigns; social engineering attacks; website defacement; distributed denial of service (DDoS) attacks; SQL injection exploits; man-in-the middle (MITM) attack vectors etc.

• DDoS attacks

  • Works by overwhelming a network with a flood of internet traffic

  • Can be mitigated by increasing the bandwidth

• SQL Injection

  • A code injection

  • Placed malicious code in SQL statements —> input these statements into entry fields

  • Targets vulnerabilities in web applications’ databases

  • Can read and manipulate data

Parallel and Distributed Computing

Parallel Computing

• Parallel computing solution takes as long as the longest of the tasks done in parallel.

  • A parallel computing solution takes as long as its sequential tasks plus the longest of its parallel tasks.

• Parallel computing can consist of a parallel portion and a sequential portion.

Why Is Parallel Computing Used?

• Parallel computing is needed for real-world simulations and modeling.

• Multiple processors can operate independently but share the same memory resources.

Distributed Computing

• Distributed computing allows problems to be solved that could not be solved on a single computer because of either the processing time or storage needs involved.

• Parallel computing uses a single computer with multiple processors.

• Distributed computing uses multiple computing devices to process those tasks.

Content distributing networks

• Stores content in multiple geographical locations

• When a user requests content, it can be received from the nearest server location

  • Reduces the time it takes for the content to travel over the internet

Cloud services

• Allows you to easily scale your resources up and down based on your current needs

  • Cloud computing resources —> scalability

• Useful for testing applications

HTTP vs HTTPs

• HTTP: Many people can attack websites

• HTTPs (Hypertext Transfer Protocol Secure): Protests the privacy of users and prevents tampering

  • A.K.A. HTTP over TLS —> encrypts HTTP requests and responses with TLS protocol

  • Ensures that only the browser and secured domain can see the data in the HTTP requests and responses

  • Prevents tampering with website content —> TLS can detect packet alterations