Understanding Bits, Bytes, and Data Representation

What are the two states of a bit?

On or off.

How many distinct values can a sequence of x bits represent?

2^x distinct values.

What is the maximum number that can be represented with n bits?

2^n - 1.

How many bits are in a byte?

8 bits.

How do you convert bits to bytes?

Divide by 8.

How do you convert bytes to bits?

Multiply by 8.

What is Floating Point Representation?

Scientific notation in base 2 used to represent non-integers.

What is the structure of a 64-bit floating point number?

1 bit for the sign, 11 bits for the exponent, 52 bits for the number.

What is an overflow error?

When you try to represent data greater than the maximum capacity of the data type.

What is a roundoff error?

When a computer cannot store infinite numbers, causing truncation or rounding off.

What does encoding in binary represent?

It represents the desired data type.

What are ASCII and Unicode?

Character sets used for representing text.

What is UTF-8?

An encoder for both Unicode and ASCII.

How does UTF-8 determine the number of bytes for a character?

By looking at the number of 1's in the first byte.

What is the difference between analog data and digital data?

Analog data is continuous, while digital data is finite and represented in binary.

What are the three steps to convert analog to digital data?

Sampling, Quantization, Binary Encoding.

What is the Nyquist-Shannon Sampling Theorem?

The sampling rate must be greater than twice the highest frequency in the signal.

What is bit depth?

The number of bits per sample.

What is lossless compression?

Reduces file size without losing any data.

What is lossy compression?

Reduces file size by removing unimportant data.

What is RLE Compression?

A method that replaces each row with numbers indicating how many consecutive pixels are the same color.

What is Chroma Subsampling?

A technique that keeps brightness while reducing color information.

What is Perceptual Audio Coding?

A method that removes inaudible sounds to reduce audio file size.

What does IP stand for in networking?

Internet Protocol, which uniquely identifies every internet device.

What are TCP and UDP used for?

They are transport protocols that help with issues regarding packets in IP packets.

What is the purpose of TLS?

TLS encrypts data to secure communications over the internet.

What does HTTP stand for and where is it found?

HTTP stands for Hypertext Transfer Protocol and is found in IP packets.

What is a Local Area Network (LAN)?

A LAN is a network that covers a limited area, such as a house or school.

What distinguishes a Wide Area Network (WAN) from a LAN?

A WAN covers a large geographic area and is composed of many LANs.

What is a Data Center Network (DCN)?

A DCN is designed for minimal delay in data transmission.

How do copper cables transmit data?

Copper cables use four twisted wires to send electricity and are fast.

What is the advantage of fiber-optic cables over copper cables?

Fiber-optic cables send light, making them faster than copper cables.

What type of signals do wireless connections use?

Wireless connections transmit data using radio waves.

What is line coding in networking?

Line coding is the process of sending binary data as time-based signals (pulses of electricity or light).

What does bit rate measure?

Bit rate measures the number of bits sent per second, typically in megabits per second (mbps).

What is bandwidth in networking?

Bandwidth refers to the maximum bit rate that can be transmitted over a network connection.

What does latency or ping indicate?

Latency or ping indicates the time it takes for a bit to be sent across the network.

What is the structure of an IPv4 address?

An IPv4 address is split into four numbers ranging from 0 to 255, stored in binary (4 bytes).

What does the first two bytes of an IPv4 address represent?

The first two bytes represent the network the device is on, typically the internet service provider.

What does the last two bytes of an IPv4 address represent?

The last two bytes represent a specific device on that provider's network.

What is the main difference between IPv4 and IPv6?

IPv6 is the successor to IPv4 and uses hexadecimal for a much larger address space.

What are the components of an IP packet?

An IP packet consists of a header (20 or 24 bytes long) and data (variable length).

What is the purpose of a router in internet routing?

A router forwards packets to the final destination using a routing/forwarding table.

What is fault tolerance in networking?

Fault tolerance allows a network to continue operating despite failures due to redundancy.

What is the primary function of User Datagram Protocol (UDP)?

UDP detects corrupt packets but does not attempt to solve other problems associated with packets.

What are the steps involved in the TCP three-way handshake?

1. First computer sends a packet with SYN bit set. 2. Second computer responds with ACK & SYN bits set. 3. First computer sends a packet with ACK bit set.

What happens during the TCP timeout process?

If an ACK is not received after a timer expires, the data is resent.

What are the three parts of a domain name in the Domain Name System (DNS)?

The three parts are the third-level domain, second-level domain, and top-level domain (e.g., es.khanacademy.org).

What is a Second-Level Domain?

The name of the company, for example, wikipedia or khanacademy.

What is a Third-Level Domain (subdomain)?

It directs you to a subset of the website, such as es.khanacademy.org or spanish-khanacademy.

What is the purpose of a DNS Resolver?

To find the IP address of a domain.

What are the steps a DNS Resolver follows to find an IP address?

1. Check local cache for IP. 2. Check ISP cache. 3. Ask name servers for TLD and Host Servers.

What is HyperText Transfer Protocol (HTTP)?

A protocol used for transferring web pages, involving sending a request to an IP and receiving a response.

What are the two parts of an HTTP response?

1. Status Code 2. Header (provides information to render content).

What are the four layers of data transmission in networking?

1. Bottom Layer: Mechanism to send data. 2. 2nd Layer: Establish connection with devices. 3. 3rd Layer: Manage transportation of packets. 4. Top Layer: Protocols for web pages.

What is De Morgan's Law in logic?

!(A & B) == !A || !B, meaning NOT(A AND B) is equivalent to NOT A OR NOT B.

What are the three parts of an algorithm?

1. Sequencing: Order of operations. 2. Selection: Conditionals (If, Else). 3. Iteration: Loops (e.g., For, While).

What is empirical analysis in the context of algorithms?

A method of checking algorithms by writing code and testing it with sample inputs.

How does a Linear Search algorithm work?

It starts at the first index and iterates through the list.

How does a Binary Search algorithm work?

It repeatedly divides the search interval in half.

What are the different types of runtimes in algorithms?

1. Constant Runtimes: Do not change with input. 2. Logarithmic Time: Increases with log of input size. 3. Linear Time: Increases directly with input size. 4. Quadratic Time: Increases with input size squared. 5. Exponential Time: Increases to the power of input.

What is the difference between Polynomial and Superpolynomial time?

Polynomial Time does not increase faster than nk, while Superpolynomial Time increases faster than nk.

What is a heuristic in algorithm design?

A guide that helps algorithms make better choices, preventing them from searching every possibility.

What are undecidable problems?

Problems that can never be solved, such as Alan Turing's Halting Problem.

What is speedup in computing?

The ratio of a sequentially-based program to a parallelly-based program.

What is Distributed Computing?

A form of parallel computing where processes run on different computers, useful for complex, large-scale problems.

What is tabular data?

Data formatted in a 'table-like' structure, such as CSV (comma-separated values) or spreadsheets.

What is a database?

A system that stores data, which can be interacted with using query languages like SQL.

What is Reinforcement Learning in machine learning?

A model that interacts with its environment, receiving rewards or penalties based on its actions to optimize itself.

What are common uses of game-playing AI and navigation bots?

Unsupervised Machine Learning.

What does Unsupervised Machine Learning do?

It finds patterns in unlabeled data.

What are common applications of Supervised Machine Learning?

Classification and prediction.

What are the three parts of a Neural Network?

Input, Hidden Layers, and Output.

What connects the neurons in a Neural Network?

Weighted connections, which indicate the value of each neuron's output.

What is Big Data?

Data collected at a massive scale from sources like sensors, social media, and web tracking.

What are the risks associated with Big Data?

Security and manipulation.

What does PII stand for?

Personally Identifiable Information.

What is a VPN?

Virtual Private Network.

What is the purpose of web cookies?

To track user data across a website.

What is a Persistent Cookie?

A type of cookie that remains after the browser is closed.

What is a Session Cookie?

A type of cookie that is deleted after the browser is shut down.

What is the function of GPS?

To determine position through trilateration using signals from GPS satellites.

How does Wi-Fi Positioning System determine location?

By scanning for multiple Wi-Fi access points and measuring signal strength.

What is Fingerprinting in the context of location services?

A method that uses a list of nearby networks and their signal strengths to determine location.

What is Cell-Tower Trilateration?

A method similar to Wi-Fi Positioning System but uses cell towers to determine location.

What is IP-Based Geolocation?

Mapping an IP address to a physical location, though it is the least accurate method.

What are Phishing Attacks?

Attempts to trick users into providing personal information.

What is a Trojan Horse in malware terms?

A malicious program that appears legitimate but causes damage once downloaded.

What is the difference between a Virus and a Worm?

A Virus replicates across the same computer, while a Worm replicates across different computers.

What is Ransomware?

Malware that holds a computer hostage by encrypting user data and demanding payment for access.

What is a Security Patch?

An update to code designed to prevent malware.

What is the purpose of a Firewall?

To monitor network traffic and determine what to allow.

What is the Caesar Cipher?

A method of encryption that substitutes letters by shifting the alphabet.

What is Public Key Encryption?

Asymmetric encryption using different keys for encoding and decoding.

What are the steps involved in the TLS protocol?

TCP Handshake, client-server notification, server confirmation with digital certificate, encryption of master key, sending encrypted data, and server decryption.

What is Crowdsourcing?

The use of the internet to share knowledge, raise funds, or divide work among humans.

What is a Sensor?

A device that detects part of its environment and sends data.