Search the California Content Standards

Standard:
Explain the limitations of licenses that restrict use of computational artifacts when using resources such as libraries.

Descriptive Statement:
Software licenses include copyright, freeware, and open-source licensing schemes. Licenses are used to protect the intellectual property of the author while also defining accessibility of the code. Students consider licensing implications for their own work, especially when incorporating libraries and other resources. For example, students might consider two software libraries that address a similar need, justifying their choice of one over the other. The choice could be based upon least restrictive licensing or further protections for their own intellectual property.

Standard:
Document decisions made during the design process using text, graphics, presentations, and/or demonstrations in the development of complex programs.

Descriptive Statement:
Complex programs are often iteratively designed as systems of interacting modules, each with a specific role, coordinating for a common overall purpose. Comments are included in code both to document the purpose of modules as well as the implementation details within a module. Together these support documentation of the design process. Students use resources such as libraries and tools to edit and manage parts of the program and corresponding documentation. For example, during development of a computational artifact students could comment their code (with date, modification, and rationale), sketch a flowchart to summarize control flow in a code journal, and share ideas and updates on a white board. Students may document their logic by explaining the development process and presenting to the class. The presentation could include photos of their white board, a video or screencast explaining the development process, or recorded audio description.

Standard:
Describe ways in which abstractions hide the underlying implementation details of computing systems to simplify user experiences.

Descriptive Statement:
An abstraction is a representation of an idea or phenomenon that hides details irrelevant to the question at hand. Computing systems, both stand alone and embedded in products, are often integrated with other systems to simplify user experiences. For example, students could identify geolocation hardware embedded in a smartphone and describe how this simplifies the users experience since the user does not have to enter her own location on the phone. Alternatively, students might select an embedded device such as a car stereo, identify the types of data (e.g., radio station presets, volume level) and procedures (e.g., increase volume, store/recall saved station, mute) it includes, and explain how the implementation details are hidden from the user.

Standard:
Compare levels of abstraction and interactions between application software, system software, and hardware.

Descriptive Statement:
At its most basic level, a computer is composed of physical hardware on which software runs. Multiple layers of software are built upon various layers of hardware. Layers manage interactions and complexity in the computing system. System software manages a computing device's resources so that software can interact with hardware. Application software communicates with the user and the system software to accomplish its purpose. Students compare and describe how application software, system software, and hardware interact. For example, students could compare how various levels of hardware and software interact when a picture is to be taken on a smartphone. Systems software provides low-level commands to operate the camera hardware, but the application software interacts with system software at a higher level by requesting a common image file format (e.g., .png) that the system software provides.

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:
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:
Categorize and describe the different functions of operating system software.

Descriptive Statement:
Operating systems (OS) software is the code that manages the computer’s basic functions. Students describe at a high level the different functions of different components of operating system software. Examples of functions could include memory management, data storage/retrieval, processes management, and access control. For example, students could use monitoring tools including within an OS to inspect the services and functions running on a system and create an artifact to describe the activity that they observed (e.g., when a browser is running with many tabs open, memory usage is increased). They could also inspect and describe changes in the activity monitor that occur as different applications are executing (e.g., processor utilization increases when a new application is launched).