Yaffs - GPL Licence

Yaffs is the property of Aleph One Limited.

  • Yaffs is available free of charge under the GNU General Public Licence, version 2 (GPL).
  • Linking Yaffs to other software creates a derived work and our interpretation of linking includes dynamic and runtime linking; any use of Yaffs creates a derived work. 
  • Under the GPL, you can test Yaffs with your product on your computers. Do not distribute this test version unless your product is normally licensed under the GPL. If you do not copy and distribute it, there are no requirement under the GPL regarding distribution of a derived work.  
  • Under the terms of the GPL, derived works must be licensed using the GPL, unless you have a Commercial Licence for Yaffs.
  • When you distribute GPLed object code you must make the full source code available too, to anyone who uses your product. (Sections 3.a and 3.b of the GPL, and the sections that follow.)  

Circumstances where you need to licence Yaffs other than under the GPL include:-

  • If you want to use Yaffs, but want to distribute your code under your licence.
  • If you want to run a statically-linked commercial RTOS on top of a Yaffs filesystem.
  • if you want to sublicence Yaffs to your customers (under terms other than the GPL).
  • If you want to use Yaffs with WindowsCE version 4. WinCE version 3 can use GPL code but WinCE v.4 and later need an additional filesystem interface layer which is not part of Yaffs. This is available at extra cost; please contact us.

In these cases, our Commercial Licence is appropriate.

If you aren't sure whether your needs will be covered by the GPL version, get in touch with us.


While Yaffs is released under GPL we can provide standard support options, consulting in its application to your particular product, or development of specific features to suit your needs or hardware. 

Helping us to improve Yaffs

Although the code is downloadable at no charge, buying this product allows you to express your appreciation of Yaffs. Alternatively you can make a Donation to Aleph One Ltd via PayPal. You can do this at PayPal by sending any sum to sales@aleph1.co.uk  We shall appreciate it!