{
  fetchFromGitHub,
  stdenv,
  isWattch ? false,
}:
stdenv.mkDerivation {
  pname =
    if isWattch
    then "wattchg7"
    else "SimpleSim";
  version =
    if isWattch
    then "master-2014-03-20"
    else "2003-10-08"; # !!!

  src =
    if isWattch
    then
      fetchFromGitHub
      {
        repo = "wattchg7";
        owner = "n-sreek";

        rev = "b1c2c1447584b7e850c6dc0743a2209c9d021a39";
        sha256 = "sha256-JMM2+6dgReSP3MKSC0ZOYt0Pcmef8DRzIkC26e4dk+Y=";
      }
    else
      fetchTarball {
        name = "simplesim-3.0";

        url = "https://www.cse.iitd.ac.in/~cs5070217/csl718/simplesim-3v0d.tgz";
        sha256 = "sha256:022rlniimzl30c1874765hl001dxc716vfwm40ij256h1qk2dwgw";
      };

  configurePhase = ''
    make config-pisa
  '';

  installPhase =
    ''
      mkdir -p $out/bin
    ''
    + (
      if isWattch
      then ''
        cp sim-outorder $out/bin/wattch-outorder
      ''
      else ''
        cp {sim-{outorder,cache,profile,bpred,eio,safe,fast},sysprobe} $out/bin/
      ''
    );
}