anchor.diff:      chmod 755 "$TMPDIR"
       echo "running nixos-install..."
       nixos-install --root $root --no-bootloader --no-root-passwd \
  -      --system ${config.system.build.toplevel} --channel ${channelSources} --substituters ""
  +      --system ${config.system.build.toplevel} \
  +      ${if copyChannel then "--channel ${channelSources}" else "--no-channel-copy"} \
  +      --substituters ""
   
       diskImage=nixos.raw
   
  
positive.code:   users   = map (x: x.user  or "''") contents;
    groups  = map (x: x.group or "''") contents;
  
    closureInfo = pkgs.closureInfo { rootPaths = [ config.system.build.toplevel channelSources ]; };
  
    blockSize = toString (4 * 1024); # ext4fs block size (not block device sector size)
  
  
negative.code: 
  , # Disk image format, one of qcow2, qcow2-compressed, vdi, vpc, raw.
    format ? "raw"
  
  , # Whether a nix channel based on the current source tree should be
    # made available inside the image. Useful for interactive use of nix
    # utils, but changes the hash of the image when the sources are
    # updated.
    copyChannel ? true
  }:
  
  assert partitionTableType == "legacy" || partitionTableType == "legacy+gpt" || partitionTableType == "efi" || partitionTableType == "hybrid" || partitionTableType == "none";
  