AP Computer Science Principles Review

• Byte


  8 bits (digits) 0-255
• Bit


  A single unit of information in a computer
• Binary numbers


  A number system with a base of 2 and two possible different digits
• Decimal number


  A number with the base of 10 with 10 possible different digits
• Binary can only precisely represent some fractional values
• Fractional values that cannot be precisely represented in binary

  • 0.34
  • 0.025
  • 0.0125
• Overflow Error


  Error from attempting to represent a number that is too large
• Round off Error


  Error from attempting to represent a number that is too precise
• Analog Data


  Data with values that change continually, or smoothly, over time
• Examples of Analog Data


  • Music
  • Position of a sprinter during a race
  • Painting
• Digital Data is data that changes discreetly through a finite set of values
• Sampling is a process for creating a digits, representation of analog data by measuring the analog data at regular intervals called samples.
• Lossless Compression is a process for reducing the number of bits needed to represent something without any information This is reversible
• Layers of Abstraction are

  Digital Image Layer

  Sampling Layer

  Pixel Layer

  Binary layer
• Lossy Compression is a process for reducing the number of bits needed to represent something in which some info is lost or thrown away this is not reversible.
• Computing Device is a machine that can run a program including computers, tablets, servers, and routers.
• Computing System is a group of computing devices and programs working together for a common purpose
• Computing Network is a group of interconnected computing devices capable of sending or reviewing messages
• Path is the series of connections between computing devices on a network a starting with sender and ending with a receiver.
• Bandwidth is the maximum amount of data that can be sent in A fixed amount of time, usually measured in bits per second
• Protocol is an agreed upon set of rules that specify the behavior of some system
• IP ADDRESS - A unique number assigned to a device on the internet
• Internet Protocol is a protocol for sending data across The internet that assigns unique number (IP address) to each connect device
• Router is a type of computer that forwards data across as network
• Redundancy is the inclusion of extra components so that a system can continue to work even if individual components fail for example having more than one path between two connected devices
• Fault tolerance is when a function can continue to function even after of individual components fail. This is important because components of complex systems fail all the time
• Data stream is info passed through the internet in packets
• Packet is a chunk of data sent over a network. Larger messages are divided into packets that may arrive in order out of order or not at all
• Packet Metadata is data added to packets to help route them through the network and reassemble the original message
• Transmission Control Protocol TCP is a protocol for sending packets that does error checking to ensure all packets are received and properly ordered
• User datagram protocol is a protocol for sending packets quickly with minimal error checking and no resending for dropped packets
• The Domain Name System is the system responsible for translating Domain names like (example.com) in to IP ADRESSES
• World Wide Web is a system of linked page, programs, and files
• Hyper Transfer Protocol isa protocol for computers to request and share the pages that make up the World Wide Web on the internet
• Input: what is put in, taken in, or operated on by any process or system
• Output any data that are sent from a program
• Program statement: A statement that is used to specify the program to be executed.
• Program is a collection of programs statements
• Documentation is an unwritten description of how a command or piece of code works or was developed
• Comment is a form of documentation