# Installation of the SimH pdp11 simulator 

The w11 project uses the pdp11 simulator from the
[SimH](https://en.wikipedia.org/wiki/SIMH) project. The project was started
by Bob Supnik under [simh.trailing-edge.com](http://simh.trailing-edge.com).
This site contains the "classic" version of SimH, the 3.X stream, with v3.11-1
as the last release. Since about 2014 the project is continued by a team led by
Mark Pizzolato as GitHub project [simh/simh](https://github.com/simh/simh).
The new, functionally much enhanced, version is called V4.*. However, the
team decided not to provide releases anymore, just a stream of commits,
more than 4200 as of April 2022.

Debian and Ubuntu offer `simh` packages, but with the obsolete version V3.8.1,
released in February 2009. The main obstacle to the inclusion of newer
versions is, according to the Debian maintainer, the unclear license situation.

The only practical way to obtain the pdp11 simulator is by installation from
sources. The GitHub repository contains also the classical versions, nicely
marked with tags.

The `scmd` scripts provided in the w11 project were originally developed for
SimH 3.8, and worked for SimH 3.9 and later releases. The SimH 4.* development
over time became incompatible with the `scmd` scripts used for w11 verification.
See issue [#30](https://github.com/wfjm/w11/issues/30) for details.

The bottom line at the moment:
- install SimH from [simh/simh](https://github.com/simh/simh)
- checkout `v3.11-1`

## SimH license changes
The maintainer of the [simh/simh](https://github.com/simh/simh) GitHub project,
[Mark Pizzolato](https://github.com/markpizz), decided on May 15th, 2022 with
commit [ce2adce6](https://github.com/simh/simh/commit/ce2adce6) to change the
license of the repository. The bottom line of the change is, that some files
are declared proprietary and this repository is no longer a
[FOSS](https://en.wikipedia.org/wiki/Free_and_open-source_software) project,
see also issue [#1163](https://github.com/simh/simh/issues/1163).
This triggered massive reactions, see issue
[#1161](https://github.com/simh/simh/issues/1161) and discussions on the
SimH mailing list [simh@groups.io](https://groups.io/g/simh), starting with post
[New license?](https://groups.io/g/simh/topic/new_license/91108560).
See especially Bob Supnik's post
[SimH licensing and the state of the project](https://groups.io/g/simh/topic/simh_licensing_and_the_state/91173868).

Given that situation using version `v3.11-1` as described above is the
only prudent option for the time being.

## Open-SimH relaunch
The post
[Announcing the Open SIMH project](https://groups.io/g/simh/topic/91528716)
announed on 2022-06-03 a re-launch of SimH as FOSS project.
A new repository [open-simh/simh](https://github.com/open-simh/simh#readme)
has been set up and provides the SimH code-base under an
[MIT-style licence](https://en.wikipedia.org/wiki/MIT_License), see
[LICENSE.txt](https://github.com/open-simh/simh/blob/master/LICENSE.txt).

The community will certainly move to open-simh, so best solution is currently
- install SimH from [open-simh/simh](https://github.com/simh/open-simh)
- checkout `v3.11-1`