NOTE: these steps refer to installing the Ruby version of Synthea on Windows -- the Ruby version of Synthea has been retired so these steps are not necessary to install the current Java implementation. These installation steps are preserved for posterity

Installing Synthea on a Windows system that hasn't had any Ruby on it before took a little more effort. These are all the steps I had to do on a Windows 7 X64 machine. An alternative is to use a Docker container.

Note: the 'cd', 'git' and other commands are to be run from a command line window (cmd.exe).

1. Download Ruby 2.3.1 (X64) from RubyInstaller.org (direct link)

   1. run the installer and install it to C:\Programs\Ruby23-x64\

2. Download the DevKit for Ruby 2.0 and above, for x64 from RubyInstaller.org (direct link)

   1. run the installer: it wil auto-unzip,
      unzip it to C:\Programs\Ruby23-x64\DevKit
   2. register the DevKit in your path with devkitvars.bat / .ps1, included in this directory
      if you skip this, you wil get in trouble with the installation of bson, a part of step 5e.

3. Log off & on again to reload the changed environment variables.

4. Install rubygems-update 2.6.7, primarily to get an updated certificate

   1. otherwise you will encounter:

      SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed

   2. we follow these instructions:

      1. Download the update
      2. cd c:\programs\ruby (or anywhere, gem is now in your path).
      3. gem install --local \rubygems-update-2.6.7
      4. update_rubygems --no-ri --no-rdoc

5. Now we can follow the instructions on the Synthea Git page

   1. cd c:\git
   2. git clone https://github.com/synthetichealth/synthea.git
   3. cd synthea
   4. gem install bundler
   5. bundle install

6. Check your hosts file:

   1. %SystemRoot%\System32\drivers\etc\hosts (you can open it in Notepad.exe)
   2. make sure the line '127.0.0.1 localhost' is present and uncommented.
   3. otherwise the Ruby MongoDB driver Moped / Mongoid won't find your Mongo service.