eT-Kernel is an upgraded version of open source RTOS T-Kernel 2.0, extended with unique eSOL technology for embedded systems. Taking advantage of the specific T-License2.0 of T-Kernel 2.0, it can be commercialized without making the software open-source. Source code is provided to eSOL customers however to allow more efficient development and integration. 

The core of all eT-Kernel profiles, eT-Kernel Compact, has been certified to the following Functional Safety standards.
・ISO 26262 ASIL D (For automotive)
・IEC 61508 SIL 4 (For industrial equipment)

In addition, the eSOL RTOS product development process has been certified in compliance with IEC 62304: 2006 Medical Device Software-Software Life Cycle Processes, which are safety standards for the development and maintenance of medical device software.

Product Line of eT-Kernel Safety Package

For users who strive to conform with functional safety standards, eSOL offers the following eT-Kernel Safety Packages, including various documents including a safety Manual and Safety Reports.

  • Automotive Safety Package (ISO 26262-compliant)
  • Industrial Safety Package (IEC 61508-compliant)

Open source T-Kernel has been extended

As an RTOS vendor, eSOL has put great effort and know-how into enhancing T-Kernel 2.0 (distributed by TRON Forum) with T-Kernel/Standard Extension source code as a basis. When compared to open source T-Kernel, eT-Kernel offers the following additional features:  

  • High-speed operation for the entire system with "Fast Boot"
  • "Logical File System (LFS)" offers transparent access to multiple file systems
  • "Exception Manager" offers problem-solving support while the system is running
  • "Target Shell" adds extended commands, useful for final system maintenance and inspection
  • Multi-core compatibility using a unique scheduling method makes it possible to mix SMP and AMP
  • System protection function helps to ensure multi-core system quality and reliability
  • Unique verification in addition to standards test suite

Compatibility with T-Kernel is retained 

    eT-Kernel retains backward-compatibility with TRON Forum’s T-Kernel 2.0. eSOL is certified by Tron Forum to distribute a modified version of their product, so that you can use eT-Kernel with peace of mind.

Two profiles available 

Two profiles are available so that you can select what is best for your system’s scale and usage requirements. One model is small, resembling µITRON with excellent real-time capability; another includes a process model with the same memory protection function as Linux.

RTOS for large-scale systems, featuring memory protection and process model

Compact RTOS with remarkable real-time capability, with a structure resembling μITRON

Multi-core compatible, able to mix SMP and AMP

A multi-core compatible version called eT-Kernel MCE (*Multi-Core Edition) is available. Even when using the eT-Kernel MCE, an ideal profile can be selected from the option above. A unique "Blended Scheduling" technology allows mixing SMP-type programs and AMP-type programs in a single system. Also, a system protection function helps to ensure complex multi-core system quality and reliability.

Multi-Core processor compatible eT-Kernel

Software assets can be re-used with two profiles 

Since core kernels are the same for eT-Kernel Extended and eT-Kernel Compact, developments such as device drivers and middleware can be re-used as kernel applications. When the user has a product line and wants to change the profile to match a product series, development can run effectively while re-using software.

eBinder offers an efficient development for all two profiles  

eBinder is available as a development environment for T-Kernel based embedded software development. eBinder can be used for development with eT-Kernel Compact and eT-Kernel Extended. eT-Kernel MCE is also supported. There is no need to learn how to use new development tools, etc. each time you change your OS or profile, allowing you to move forward with development more efficiently.

Logical File System supports POSIX file system APIs  

A Logical File System (LFS) is provided, providing ANSI/POSIX file system APIs. It is fully integrated with the provided thread-safe C library. It can be called from anywhere, including processes and kernel applications including system programs. FAT file system is integrated as a standard file system that can be used via POSIX interface. 

Successfully implemented in various fields 

eT-Kernel has been successfully deployed in a wide range of diverse fields. It is also being used for numerous products that are currently under development. 

Source code and documentation provided 

eT-Kernel provides the source code for each of its three profiles.
Comprehensive documentations are provided as well, including a User Guide, Board Support Guide, Getting Started document, etc.

Maintenance and customization services 

Using maintenance services allows you to safety use eT-Kernel to tackle development tasks. eT-Kernel includes the following maintenance services : 

  • Product-related queries are accepted and answered through email
  • Minor version upgrades and bugfixes

Also, a customization service is provided to ensure eT-Kernel is compatible with your specific hardware and different development environments.

T-Kernel framework

T-Kernel’s software architecture features a flexible, layer-type scalable structure, allowing you to change it accordingly to match the system you’re developing. Various setups are available to promote re-use of software. A simple explanation of each program feature that makes up the architecture is provided here.


T-Kernel consists of: The T-Kernel/Operating System (T-Kernel/OS), the T-Kernel/System Manager (T-Kernel/SM), and T-Kernel/Debugger Support (T-Kernel/DS). The list below shows their functions. T-Kernel/OS is the main part of T-Kernel and includes all task management features, memory management features, and system control features included in a standard Real-Time OS such as µITRON. T-Kernel/OS can only be called T-Kernel in a strict sense.

(Operating System)
(System Manager)
(Debugger Support)
    • Task management
    • Task-included synchronization
    • Task-excluded processing
    • Synchronization / communication
    • Memory pool management
    • Time management
    • Interruption management
    • System status management
    • Subsystem status management
    • System memory management
    • Address space management
    • Device management
    • Interruption management
    • I/O port access support
    • Energy saving management
    • System structure information management
    • Memory cache control
    • Physical timer
    • Utility
    • Subsystem and device driver operation
    • Kernel internal status acquisition
    • Execution trace

Device drivers

T-Kernel follows the device driver specifications prescribed for driver interfaces and drivers. When transitioning programs that use a driver to a new hardware environment, driver interface standardization allows you to re-use applications such as middleware and libraries without changing interface parts.


A subsystem is a setup used for expanding T-Kernel functions. As shown in the diagram, subsystems operate in T-Kernel, with T-Kernel/OS offering a subsystem management function. T-Kernel can also be statically linked to or statically loaded. For example, middleware such as the file system and the TCP/IP protocol stack can be implemented as subsystems. User-created unique libraries, etc. can also be added as subsystems. By implementing middleware or user-created libraries as subsystems, a shared interface can be provided for upper-level applications. Also, since subsystems do not depend on a CPU or board thanks to the layer-type T-Kernel architecture, subsystems simply need to be recompiled to operate when changing hardware, with no repair necessary.

Use Case

Related materials

Catalog: Embedded Software Platform Products and Services (P) Embedded Software Platform Products and Services (20 pages)

Leaflet: Embedded Platform Solutions with RTOS (P) Leaflet: Embedded Platform Solutions with RTOS


Materials available for Download!