| # Overview |
| |
| Fuchsia is an open-source operating system designed from the ground up for |
| security and updatability. |
| |
| ## Fuchsia is… |
| |
| ### Fuchsia is designed for security and privacy |
| |
| Security and privacy are woven deeply into the architecture of Fuchsia. The |
| basic building blocks of Fuchsia, the kernel primitives, are exposed to |
| applications as object-capabilities, which means that applications running on |
| Fuchsia have no ambient authority: applications can interact only with the |
| objects to which they have been granted access explicitly. |
| |
| Software is delivered in hermetic packages and everything is sandboxed, which |
| means all software that runs on the system, including applications and system |
| components, receives the least privilege it needs to perform its job and gains |
| access only to the information it needs to know. |
| |
| ### Fuchsia is designed to be updatable |
| |
| Fuchsia works by combining components delivered in packages. Fuchsia packages |
| are designed to be updated independently or even delivered ephemerally, which |
| means packages are designed to come and go from the device as needed and the |
| software is always up-to-date, like a Web page. |
| |
| Fuchsia aims to provide drivers with a binary-stable interface. In the future, |
| drivers compiled for one version of Fuchsia will continue to work in future |
| versions of Fuchsia without needing to be modified or even recompiled. This |
| approach means that Fuchsia devices will be able to update to newer versions of |
| Fuchsia seamlessly while keeping their existing drivers. |
| |
| ### Fuchsia is designed to be language and runtime agnostic |
| |
| Fuchsia currently supports a variety of languages and runtimes, including C++, |
| Rust, Flutter, and Web. Fuchsia is designed to let developers bring their own |
| runtime, which means a developer can use a variety of languages or runtimes |
| without needing to change Fuchsia itself. |
| |
| Applications interact with each other and the system using message passing, |
| which means any application that can format messages appropriately can |
| participate fully in the system regardless of its language or runtime. Fuchsia |
| is defined by these protocols, much like the Internet is defined by its |
| protocols rather than a particular client or server implementation. |
| |
| ### Fuchsia is designed for performance |
| |
| Fuchsia makes heavy use of asynchronous communication, which reduces latency by |
| letting the sender proceed without waiting for the receiver. Fuchsia optimizes |
| memory use by avoiding garbage collection in the core operating system, which |
| helps to minimize memory requirements to achieve equivalent performance. |
| |
| ### Fuchsia is open source |
| |
| Fuchsia is built in the open using BSD/MIT-style open source licenses. |
| Fuchsia has an inclusive community that welcomes high-quality, well-tested |
| contributions from everyone. |
| |
| ## Fuchsia is not… |
| |
| ### Fuchsia is not based on Linux |
| |
| Fuchsia does not use the Linux kernel. Instead, Fuchsia has its own kernel, |
| Zircon, which evolved from LittleKernel. Fuchsia implements some, but not all, |
| of the POSIX specification as a library on top of the underlying kernel |
| primitives, which focus on secure message passing and memory management. Many |
| core system services, such as file systems and networking, run outside the |
| kernel in least-privilege, need-to-know sandboxes. |
| |
| ### Fuchsia is not a microkernel |
| |
| Although Fuchsia applies many of the concepts popularized by microkernels, |
| Fuchsia does not strive for minimality. For example, Fuchsia has over 170 |
| syscalls, which is vastly more than a typical microkernel. Instead of |
| minimality, the system architecture is guided by practical concerns about |
| security, privacy, and performance. As a result, Fuchsia has a pragmatic, |
| message-passing kernel. |
| |
| ### Fuchsia is not a user experience |
| |
| Fuchsia is not tied to a specific end-user experience. Instead, Fuchsia is |
| general purpose and contains the building blocks necessary for creating a wide |
| variety of high-quality user experiences. |
| |
| Fuchsia does have a developer experience, which lets developers write software |
| for Fuchsia via SDKs and tools. |
| |
| ### Fuchsia is not a science experiment |
| |
| Fuchsia's goal is to power production devices and products used for |
| business-critical applications. As such, Fuchsia is not a playground for |
| experimental operating system concepts. Instead, the platform roadmap is driven |
| by practical use cases arising from partner and product needs. |
