Unit 4: How the Internet WorksLab 1: Computer Networks4.1.1 Show
4.1.1
Your computer probably uses a router that is somewhere in your home to connect to your ISP. The computers connected to the Internet and the connections among them don't belong to any one organization. Different ISPs provide the Internet to different communities. And typically within a large organization (such as a university), the Internet connections are provided by the organization itself. 4.1.1
4.1.2 CSN-1.A.5, CSN-1.A.6, CSN-1.B.6, CSN-1.E.2, CSN-1.E.5
4.1.3 CSN-1.B.3, CSN-1.C.1
4.1.3 TCP/IP is a pair of protocols that provide two levels of abstraction:
Lab 2: Cybersecurity4.2.1: Encryption and Decryption
4.2.1: Symmetric Encryption Substitution ciphers are examples of symmetric encryption because they use the same key for both encryption and decryption. 4.2.3 Public key encryption uses a pair of keys: a public key for encryption and a private key for decryption. The sender uses the public key to encrypt the message, and receiver uses their private key to decrypt it. 4.2.3 SSL/TLS (secure sockets layer/transport layer security) is the standard used for cryptographically secured information transfer on the Internet. 4.2.3 Certificate authorities are organizations that issue digital certificates to verify who owns the encryption keys used for secured communications. Instead of trusting that the website is who they say they are, you now have to trust that the Certificate Authority is reliable. 4.2.5
4.2.5 A DDoS (Distributed Denial of Service) attack uses a virus to flood a server with many requests from many computers at once so that users of that server are denied service. 4.2.5: A rogue access point is a wireless access point that gives access to a secure network without the authorization of the network administrator. Lab 3: Community and Online Interactions4.3.5 The digital divide refers to unequal access to computers and the Internet based on poverty, racism, sexism, isolation in the countryside, age, and other factors. The digital divide affects both individuals within a country and countries themselves. 4.3.6
4.3.6
Lab 4: Data Representation and Compression4.4.1: Bit DAT-1.A.3 A bit is a single unit of data that can only have one of two values. We usually represent the two values as 0 (off) and 1 (on). 4.4.1: Byte and Word A byte is eight bits. A word is a sequence of however many bits the CPU processes at a time. As of 2017, words are 32 or 64 bits. 4.4.2 A binary sequence (also called a bitstream) is a string of ones and zeros. 4.4.2 Analog data have values that change smoothly, unlike digital data which change in discrete intervals. Sampling means measuring values, called samples, of an analog signal at regular intervals. The sampling rate is the number of samples measured per second. 4.4.3 width: the number of bits that a CPU processes at a time word: a binary sequence of that many bits 4.4.4 Scientific notation (such as 2,350,000 = 2.35 × 106) uses powers of ten to represent very large or very small values. Floating point is the same idea but with powers of two. 4.4.5: Bit DAT-1.A.3 The word "bit" is an abbreviation for binary digit. 4.4.6: Lossless Compression Lossless data compression algorithms (such as PNG) are reversible (there is no loss in quality); you can reconstruct the original data. 4.4.6: Lossy Compression Lossy data compression algorithms are not fully reversible; you can reconstruct only an approximation of the original data. Which device can be used to send data into the computer?The most common input devices are the keyboard, mouse, and touch screen. Portable keyboard, wireless mouse, and iPhone. There are hundreds of other input devices, like microphones to capture sound waves, scanners to capture image data, and virtual reality devices to capture our body movements.
Can be a devices which is capable of sending or receiving data?A computer network is any group of interconnected computing devices capable of sending or receiving data. A computing device isn't just a computer—it's any device that can run a program, such as a tablet, phone, or smart sensor.
Which devices allows us to receive information from the computer?Output devices allow us to receive information from the computer. An output device is any hardware device used to send data from a computer to another device or user. monitors and projectors (video), headphones and speakers (audio), or printers and plotters (physical reproduction in the form of text or graphics).
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