Nuttx is a real-time embedded operating system (RTOS). It has a small footprint that is usable in micro-controller environments. It is fully scalable from tiny (8-bit) to moderate embedded (32-bit) systems. It also aims to be fully compliant to standards, to be fully real time, and to be totally open.
Embedthis Appweb is a fast, little embedded Web server. It is unmatched in efficiency and serves pages at native speed, using an event-driven, non-blocking core to serve multiple requests using minimal resources. It has integrated caching and the Embedded Server Pages C-Language Web framework. Without compromising performance, it has extensive security controls and a rigorous security sandbox that helps protect the server and mitigate denial-of-service attacks. It is one of the most widely deployed embedded Web servers and is used in networking equipment, telephony, mobile devices, industrial control, and consumer and office equipment, and in high-performance Web services.
catnip is a tiny network packet mirroring tool. The server (source) is not based on libpcap and, when compiled and stripped, makes the binary smaller than 20kiB. This makes it very suitable for embedded environments where a libpcap-based tool, typically 100kiB for just libpcap and 500kiB for tcpdump, would be simply too large. What makes catnip stand out from other small packet capturing tools is that it presents the remote systems interface as a local TUN/TAP interface, but additionally can apply a BPF filter at the remote end to send to you only the traffic you are interested in.
The CyaSSL embedded SSL library is a lightweight SSL library written in ANSI C and targeted for embedded and RTOS environments, primarily because of its small size, speed, and feature set. It is commonly used in standard operating environments and cloud services as well because of its royalty-free pricing and excellent cross platform support. CyaSSL supports industry standards up to the current TLS 1.2 and DTLS 1.2 levels, is up to 20 times smaller than OpenSSL, and offers progressive ciphers such as HC-128, RABBIT, and NTRU.
musl is a new implementation of the standard library for Linux-based systems. It is lightweight, fast, simple, free, and strives to be correct in the sense of standards-conformance and safety. It includes a wrapper for building programs against musl in place of the system standard library (e.g. glibc), making it possible to immediately evaluate the library and build compact statically linked binaries with it.
QP is a family of lightweight software frameworks for building responsive and modular real-time embedded applications as systems of cooperating, event-driven active objects (actors). The QP family consists of QP/C, QP/C++, and QP-nano frameworks, which are all strictly quality controlled, superbly documented, and commercially licensable. The behavior of active objects is specified in QP by means of hierarchical state machines (UML statecharts). The frameworks support manual coding of UML state machines in C or C++ as well as automatic code generation by means of the free QM modeling tool. All QP frameworks can run on bare-metal MCUs, completely replacing a traditional RTOS. Ports and ready-to-use examples are provided for all major CPUs, such as ARM Cortex-M, ARM7/9, MSP430, C28x, C55x, RX, R8C, AVR32, AVRMega, PIC24/dsPIC, as well as Arduino and mbed. QP/C and QP/C++ can also work with a traditional OS/RTOS, such as: POSIX (Linux, QNX), Windows, VxWorks, ThreadX, and uC/OS.
yaSSL is a C++ based SSL library for embedded and RTOS environments, designed for individuals who prefer to use the C++ language. For a C-based solution, please see CyaSSL. yaSSL supports the industry standards up to TLS 1.2, and also includes an OpenSSL compatibility interface.
execline is a very light, non-interactive scripting language, which is similar to a shell. Simple shell scripts can be easily rewritten in the execline language, improving performance and memory usage. execline was designed for use in embedded systems, but works on most Unix flavors.
Fakeroot-ng runs a program while fooling it into thinking it is running with root privileges. When the program does something that only root can do (e.g. create a device file), fakeroot-ng emulates the appropriate system calls so that the program gets a consistent view of its actions. Unlike the original fakeroot, fakeroot-ng uses the ptrace interface, which means that it does not suffer some of the limitations that fakeroot does. In particular, fakeroot-ng supports chroot jails.