The PiDP-8/I software distribution is an agglomeration of software from multiple sources. Several different licenses apply to its parts. This file guides you to those individual licenses.
SIMH License
Most of the files in this software distribution are released under the terms of the SIMH license, a copy of which typically appears at the top of each file it applies to. This includes not only SIMH proper but also several files written by PiDP-8/I software project contributors who chose to license their contributions under the same license, including E8.
For a few files, textual inclusion of the license inside the file itself was impractical, so this license is applied by reference to a file included with the distribution.
PiDP-8/I Design Files
The PiDP-8/I design files in hardware/pidp8i were released
under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0
International license on the mailing list by their
author, Oscar Vermeulen.
autosetup License
The configure script and the contents of the autosetup directory are
released under the FreeBSD license given in autosetup/LICENSE.
palbart License
The palbart program and its manual page are released under the terms
of the license given in src/palbart/LICENSE.md.
d8tape License
The d8tape program is distributed under the license given in
src/d8tape/LICENSE.md.
CC8 Compiler License
The license for the src/cc8 sub-tree is messy as it comes to us from
multiple authors over many years.
There are two compilers here.
First we have the OS/8 "native" compiler in src/cc8/os8, which is
entirely Ian Schofield's work, released under the terms of the GNU
General Public License version 3.
Then we have the CC8 cross-compiler which is based on Ron Cain's Small-C, originally published in Dr. Dobbs' Journal. Wikipedia describes Small-C as "copyrighted but shareable," which I take to mean that we cannot claim it as our exclusive property, but we can modify it and distribute those modifications to others, which is what we're doing here.
Ian Schofield then took the Small-C source base and added a SABR
back-end, code8.c, which is also distributed under the GPLv3.
There is another PDP-8 C compiler project based on Small-C by Vincent Slyngstad, which uses an entirely different approach for code generation. Ian Schofield took some of the library routines from this implementation.
OS/8 License
The OS/8 media images included with this software distribution are
released under the Digital License Agreement presented in
media/os8/LICENSE.md.
Other DEC Software
The other files in the media and examples directories
that originate from Digital Equipment Corporation are believed to fall
under the public domain license DEC released all their PDP-8
software under after it stopped being economically viable. Documented
releases for specific software (e.g. TSS/8) may be difficult to come by,
however.
ETOS License
ETOS was a commercial product produced outside of DEC. No public documented declaration of license is known to be available for it, but we have a third-hand report that its creators are fine with ETOS being redistributed.