UDS

Unix domain sockets (UDS) are an inter-process communication method used on Unix-like systems. They use the file system namespace or an abstract namespace (on Linux) to address endpoints, avoiding network addresses and ports. UDS supports two main types: stream sockets (SOCK_STREAM), which provide a reliable, connection-oriented channel, and datagram sockets (SOCK_DGRAM), which are message-oriented. Because they operate within the kernel and do not traverse the network stack, they typically offer lower latency and higher throughput than network sockets. Security is mainly through filesystem permissions and ownership; additional hardening can be achieved with socket namespaces. Common uses include server-daemon communication, database backends, and IPC in on-host microservices. Limitations include locality (not designed for remote hosts), portability concerns across non-Unix systems, and potential complexity when scaling beyond a single machine.

Unified Diagnostic Services (UDS) is an automotive diagnostic protocol defined by ISO 14229. It enables standardized communication between diagnostic tools and vehicle ECUs to access or control functions. Services include session control, security access, read/write data by identifier, input/output control, and diagnostic trouble code management. UDS can operate over CAN, CAN-FD, Ethernet, or other vehicle networks, depending on architecture. It is widely used for OBD-II diagnostics and for manufacturer-specific tooling, including fault code retrieval, software updates, and ECU reprogramming. Implementations vary by vendor, so conformance testing and security considerations, such as authentication and access control, are important in practice.

Other uses of the acronym UDS include historical references such as the Ubuntu Developer Summit (UDS), a planning event for Ubuntu releases, and discussions of Urban Data Space in smart-city contexts. The meaning of UDS depends on domain.