In general, new, original software developed under the ZeptoOS project is distributed under the GNU GPL / LGPL licenses, as appropriate. Those licenses can be found in the top-level directory of the ZeptoOS tarball. If you are not familiar with the GPL or LGPL licensing, please see the files above and also visit http://www.gnu.org/.
However, ZeptoOS is a collection of many existing software components, packaged and distributed under a number of licenses, such as:
- GPL / LGPL
- Linux kernel, GNU libc, FUSE, PVFS, BusyBox, iptables, NBD, psmisc,
- CPL (Common Public License)
- DCMF, SPI,
- MPICH, TAU (note that TAU is distributed separately from the ZeptoOS tarball), netkit-rsh
The important thing is that all these licenses are free/open source, OSI-approved licenses.