anchor.diff: -{ pkgs }:
  +{ pkgs
  +, linuxKernel ? pkgs.linux
  +, img ? "bzImage"
  +, rootModules ? [ "cifs" "virtio_net" "virtio_pci" "virtio_blk" "virtio_balloon" "nls_utf8" "ext2" "ext3" "unix" ]
  +}:
   
   with pkgs;
   
  
positive.code:   # The 15 second CIFS timeout is too short if the host if heavily
    # loaded (e.g., in the Hydra build farm when it's running many jobs
    # in parallel).  So apply a patch to increase the timeout to 120s.
    kernel = assert pkgs.linux.features.cifsTimeout; pkgs.linux;
  
    kvm = pkgs.qemu_kvm;
  
  
    modulesClosure = makeModulesClosure {
      inherit kernel;
      rootModules =
        [ "cifs" "virtio_net" "virtio_pci" "virtio_blk" "virtio_balloon"
          "nls_utf8" "ext2" "ext3" "unix" ];
    };
  
  
  
negative.code:       -chardev socket,id=samba,path=./samba \
        -net user,guestfwd=tcp:10.0.2.4:445-chardev:samba \
        -drive file=$diskImage,if=virtio,boot=on,cache=writeback,werror=report \
        -kernel ${kernel}/${img} \
        -initrd ${initrd}/initrd \
        -append "console=ttyS0 panic=1 command=${stage2Init} tmpDir=$TMPDIR out=$out mountDisk=$mountDisk" \
        $QEMU_OPTS
  