Keil have traditionally produced a basic RTOS for each of their compilers. Suitable for many applications where basic small and fast systems are required. Keil compilers are also compatible with and recommend Segger emBOS
The RTX Real-Time Kernel is a real-time kernel for ARM7, ARM9, and Cortex-M3 devices. It allows you to create programs that simultaneously perform multiple functions or tasks. Real-Time Library with Flash File System, TCP/IP Networking Suite, CAN Interface, USB Device Interface > Link to
RTX51 is a real-time kernel for the 8051 family of microcontrollers that is designed to solve two problems common to embedded programs. Multitasking: several operations must execute simultaneously. Real-time control: operations must execute within a defined period of time. The RTX-tiny is part of the PK51 suite. > Link to
ARTX-166 is an advanced real-time kernel for the Infineon XC16x and C16x as well as the STMicroelectronics ST10 families of microcontrollers.. > Link to