T-License

{{notability|date=June 2011}}

{{Infobox software licence

| name = T-License

| image =

| caption =

| author = TRON Forum

| version = 2.2

| publisher = TRON Forum

| date = {{Release date and age|2020|4|01|br=yes}}

| spdx =

| OSI approved =

| Debian approved =

| FSF approved =

| GPL compatible =

| copyleft =

| linking =

| website = [https://www.tron.org/download/index.php?route=information/information&information_id=62&language=en T-License]

}}

T-License is the software license used by TRON Forum {{Cite web |date=2024-05-10 |title=TRON Forum |url=https://www.tron.org/ |access-date=2024-10-12 |website=www.tron.org |language=en-US}} for distributing the source code of its real-time operating systems (RTOSs) such as T-Kernel and Micro T-Kernel (often written as μT-Kernel: μ pronounced as "micro", not "mu"). The license fee is free if products are developed according to T-License conditions.

The current version of T-License is version 2.2.

T-License has been created to fit the need of embedded computer system market where the source code may contain information tied to proprietary hardware information.

So, unlike GNU General Public License, T-License does not require the release of the (modified) source code of a program even if such a program is used by a third party.

The requirement to express that the use of T-Kernel or μT-Kernel by a logo in a product somewhere on the product itself or the manual {{Cite web |last=TRON Forum |date=2020-04-01 |title=Form of Notice for Use of Source Code of T-Kernel 2.0 under T-License 2.2 |url=https://www.tron.org/download/index.php?route=information/information&information_id=51&language=en |access-date=2024-10-12 |website=www.tron.org}} can be alleviated by a TRON Forum member. Because of this, not all products released in the market that use T-Kernel or μT-Kernel mention the use of the RTOS inside.

Usage Examples<ref>{{Cite web |title=eT-Kernel {{!}} Products {{!}} eSOL - Real-time embedded software platform solutions |url=https://www.esol.com/embedded/product/et-kernel.html |access-date=2024-10-12 |website=eSOL |language=en}}</ref>

As noted above, not all the products mention the use of T-Kernel or μT-Kernel.

Here are some examples of products or companies whose online manual refers to T-License because they either use T-Kernel or μT-Kernel.

  • A licensing sheet that is provided for Brother TD-4000 printer.: {{Cite web |last=Brother USA |title=Open Source Licensing Remarks |url=https://download.brother.com/welcome/docp100436/cv_td4000d_eng_license_100.pdf |access-date=2024-10-12}}
  • A Samsung network camera.The Japanese manual refers to T-License on page 122. {{Cite web |title=SAMSUNG TECHWIN ネットワークカメラ ユーザーマニュアル SNF-7010/SNF-7010V |url=https://www.tokaisecurity.net/pdf2/User%20Manual-SNF-7010-JAPANESE.pdf |access-date=2024-10-12}}
  • Clarion's open source web page (in Japanese) which lists the T-License among other licenses under which their products have been produced.: {{Cite web |title=Clarionクラリオン {{!}} オープンソースコードサイト |url=https://www.clarion.com/jp/ja/open-source/2017/index.html |access-date=2024-10-12 |website=www.clarion.com}}
  • Extended T-Kernel RTOS from eSOL.: {{Cite web |title=eT-Kernel {{!}} Products {{!}} eSOL - Real-time embedded software platform solutions |url=https://www.esol.com/embedded/product/et-kernel.html |access-date=2024-10-12 |website=eSOL |language=en}}
  • Customized ports of T-Kernel from Personal Media Corp. (in Japanese): {{Cite web |title=PMC T-Kernel - PMC T-Engine/T-Kernel ポータルサイト |url=http://www.t-engine4u.com/products/pmc_tk.html |access-date=2024-10-12 |website=www.t-engine4u.com}}
  • "OpenTK", an enhanced version of T-Kernel with MMU support, etc. (in Japanese) {{Cite web |title=T-Kernel 2.0 オープンソース・パッケージ「OpenTK」:日立ソリューションズ・テクノロジー |url=https://www.hitachi-solutions-tech.co.jp/eos/system/opentk/index.html |access-date=2024-10-12 |website=www.hitachi-solutions-tech.co.jp}}

There are other products that use T-Kernel or μT-Kernel under T-License. Some of them are listed at the TRON Forum web page (in Japanese). {{Cite web |last=TRON Forum |title=TRON PROJECT 30th Anniversary: Produtcs that use TRON RTOS family (in Japanese) |url=https://30th.tron.org/products.html |access-date=2024-10-12 |website=30th.tron.org}}

History

T-License was originally proposed by T-Engine Forum,{{cite web |title=T-Engine {{pipe}} Renesas Electronics |url=http://www.renesas.com/_full_product_info_/products/tools/introductory_evaluation_tools/t_engine_solution_engine/t_engine_solution_engine_mid_level_landing.jsp |url-status=dead |archive-url=https://web.archive.org/web/20111002041310/http://www.renesas.com/_full_product_info_/products/tools/introductory_evaluation_tools/t_engine_solution_engine/t_engine_solution_engine_mid_level_landing.jsp |archive-date=2 October 2011 |access-date=14 March 2022 |website=www.renesas.com}}{{Cite web |title=The T-Engine: Tomorrow Happening Today |url=http://www.itmagz.com/index.php/technology-mainmenu/news-mainmenu-41/273-the-t-engine-tomorrow-happening-today.html?showall=1 |url-status=dead |archive-url=https://web.archive.org/web/20120326140740/http://www.itmagz.com/index.php/technology-mainmenu/news-mainmenu-41/273-the-t-engine-tomorrow-happening-today.html?showall=1 |archive-date=2012-03-26 |access-date=2011-07-04 |website=itmagz.com}} which was merged into the current TRON Forum.

There is an online PDF Japanese article that explains the motivation behind T-License that was born with T-Engine, a hardware platform for developing IoT applications. {{Cite web |last=Sakamura |first=Ken |date=2004-08-01 |title=ITRON から T-Engine へ - T-Engine の思想 (From ITRON to T-Engine - The Philosophy of T-Engine) |url=https://www.cqpub.co.jp/interface/sample/200408/if0408_chap1.pdf |access-date=2024-10-12 |website=CQ 出版 (CQ Publishing Co., Ltd)}}

According to the original version of T-License, changing or modifying the T-Kernel source code could only be done by certain parties like A-members of T-Engine Forum and these parties must notify and register their changes with T-Engine Forum.http://tronweb.super-nova.co.jp/gpl-vs-t-license.html GPL vs T-License

But this restriction has been mostly lifted since the 2.0 version, which has been in force since May, 2011.[https://www.tron.org/download/index.php?route=information/information&information_id=57&language=en T-License 2.0 FAQ]

See also

References

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