Search the California Content Standards

Standard:
Identify and fix security issues that might compromise computer programs.

Descriptive Statement:
Some common forms of security issues arise from specific programming languages, platforms, or program implementation choices. Students read a given a piece of code that contains a common security vulnerability, explain the code's intended function or purpose, provide and explain examples of how a specific input could exploit that vulnerability (e.g., the program accessing data or performing in unintended ways), and implement a change in the code to mitigate this vulnerability. For example, students could review code that takes a date as input, recognize that the code doesn't check for appropriate last days of the month, and modify the code to do that. Alternatively, students could review code that supports entry of patient data (e.g., height and weight) and doesn't prompt users to double check unreasonable values (e.g., height at 6 feet and weight at 20 pounds).

Standard:
Develop and use a series of test cases to verify that a program performs according to its design specifications.

Descriptive Statement:
Testing software is a critically important process. The ability of students to identify a set of important test cases communicates their understanding of the design specifications and potential issues due to implementation choices. Students select and apply their own test cases to cover both general behavior and the edge cases which show behavior at boundary conditions. For example, for a program that is supposed to accept test scores in the range of [0,100], students could develop appropriate tests (e.g, a negative value, 0, 100, and a value above 100). Alternatively, students developing an app to allow users to create and store calendar appointments could develop and use a series of test cases for various scenarios including checking for correct dates, flagging for user confirmation when a calendar event is very long, checking for correct email address format for invitees, and checking for appropriate screen display as users go through the process of adding, editing, and deleting events.

Standard:
Modify an existing program to add additional functionality and discuss intended and unintended implications.

Descriptive Statement:
Modularity and code reuse is key in modern software. However, when code is modified, the programmer should consider relevant situations in which this code might be used in other places. Students create and document modifications to existing programs that enhance functionality, and then identify, document, and correct unintended consequences. For example, students could take an existing a procedure that calculates the average of a set of numbers and returns an integer (which lacks precision) and modify it to return a floating-point number instead. The student would explain how the change might impact multiple scenarios.

Standard:
Evaluate key qualities of a program through a process such as a code review.

Descriptive Statement:
Code reviews are a common software industry practice and valuable for developing technical communication skills. Key qualities of code include correctness, usability, readability, efficiency, and scalability. Students walk through code they created and explain how it works. Additionally, they follow along when someone else is explaining their code and ask appropriate questions. For example, students could present their code to a group or visually inspect code in pairs. Alternatively, in response to another student's presentation, students could provide feedback including comments on correctness of the code, comments on how code interacts with code that calls it, and design and documentation features.

Standard:
Use version control systems, integrated development environments (IDEs), and collaborative tools and practices (e.g., code documentation) while developing software within a group.

Descriptive Statement:
Software development is a process that benefits from the use of tools that manage complexity, iterative development, and collaboration. Large or complex software projects often require contributions from multiple developers. Version control systems and other collaborative tools and practices help coordinate the process and products contributed by individuals on a development team. An integrated development environment (IDE) is a program within which a developer implements, compiles or interprets, tests, debugs, and deploys a software project. Students use common software development and documentation support tools in the context of a group software development project. At this level, facility with the full functionality available in the collaborative tools is not expected. For example, students could use common version control systems to modify and improve code or revert to a previous code version. Alternatively, students could use appropriate IDEs to support more efficient code design and development. Additionally, students could use various collaboration, communication, and code documentation tools designed to support groups engaging in complex and interrelated work.

Standard:
Compare multiple programming languages, and discuss how their features make them suitable for solving different types of problems.

Descriptive Statement:
Particular problems may be more effectively solved using some programming languages than other programming languages. Students provide a rationale for why a specific programming language is better suited for a solving a particular class of problem. For example, students could explain how a language with a large library base can make developing a web application easier. Alternatively, students could explain how languages that support particular programming paradigms (e.g., object-oriented or functional) can make implementation more aligned with design choices. Additionally, students could discuss how languages that implement garbage collection are good for simplicity of memory management, but may result in poor performance characteristics.

Standard:
Illustrate ways computing systems implement logic through hardware components.

Descriptive Statement:
Computing systems use processors (e.g., a central processing unit or CPU) to execute program instructions. Processors are composed of components that implement the logical or computational operations required by the instructions. AND, OR, and NOT are examples of logic gates. Adders are examples of higher-leveled circuits built using low-level logic gates. Students illustrate how modern computing devices are made up of smaller and simpler components which implement the logic underlying the functionality of a computer processor. At this level, knowledge of how logic gates are constructed is not expected. For example, students could construct truth tables, draw logic circuit diagrams, or use an online logic circuit simulator. Students could explore the interaction of the CPU, RAM, and I/O by labeling a diagram of the von Neumann architecture. Alternatively, students could design higher-level circuits using low-level logic gates (e.g., adders).

Standard:
Examine the scalability and reliability of networks, by describing the relationship between routers, switches, servers, topology, and addressing.

Descriptive Statement:
Choice of network topology is determined, in part, by how many devices can be supported and the character of communication needs between devices. Each device is assigned an address that uniquely identifies it on the network. Routers function by comparing addresses to determine how information on the network should reach its desgination. Switches compare addresses to determine which computers will receive information. Students explore and explain how network performance degrades when various factors affect the network. For example, students could use online network simulators to describe how network performance changes when the number of devices increases. Alternatively, students could visualize and describe changes to the distribution of network traffic when a router on the network fails.

Standard:
Explain how the characteristics of the Internet influence the systems developed on it.

Descriptive Statement:
The design of the Internet includes hierarchy and redundancy to help it scale reliably. An end-to-end architecture means that key functions are placed at endpoints in the network (i.e., an Internet user's computer and the server hosting a website) rather than in the middle of the network. Open standards for transmitting information across the Internet help fuel its growth. This design philosophy impacts systems and technologies that integrate with the Internet. Students explain how Internet-based systems depend on these characteristics. For example, students could explain how having common, standard protocols enable products and services from different developers to communicate. Alternatively, students could describe how the end-to-end architecture and redundancy in routing enables Internet users to access information and services even if part of the network is down; the information can still be routed from one end to another through a different path.