@@ -40,6 +40,7 @@ import (

 	"github.com/docker/docker/pkg/pidfile"

 	"github.com/docker/docker/pkg/plugingetter"

 	"github.com/docker/docker/pkg/signal"

+	"github.com/docker/docker/pkg/system"

 	"github.com/docker/docker/plugin"

 	"github.com/docker/docker/registry"

 	"github.com/docker/docker/runconfig"

@@ -210,6 +211,10 @@ func (cli *DaemonCli) start(opts *daemonOptions) (err error) {

 		logrus.Fatalf("Error creating middlewares: %v", err)

 	}

+	if system.LCOWSupported() {

+		logrus.Warnln("LCOW support is enabled - this feature is incomplete")

+	}

+

 	d, err := daemon.NewDaemon(cli.Config, registryService, containerdRemote, pluginStore)

 	if err != nil {

 		return fmt.Errorf("Error starting daemon: %v", err)

@@ -14,6 +14,7 @@ import (

 	"github.com/docker/docker/image"

 	"github.com/docker/docker/layer"

 	"github.com/docker/docker/pkg/progress"

+	"github.com/docker/docker/pkg/system"

 	refstore "github.com/docker/docker/reference"

 	"github.com/docker/docker/registry"

 	"github.com/docker/libtrust"

@@ -143,8 +144,8 @@ func (s *imageConfigStore) RootFSFromConfig(c []byte) (*image.RootFS, error) {

 	}

 	// fail immediately on Windows when downloading a non-Windows image

-	// and vice versa

-	if runtime.GOOS == "windows" && unmarshalledConfig.OS == "linux" {

+	// and vice versa. Exception on Windows if Linux Containers are enabled.

+	if runtime.GOOS == "windows" && unmarshalledConfig.OS == "linux" && !system.LCOWSupported() {

 		return nil, fmt.Errorf("image operating system %q cannot be used on this platform", unmarshalledConfig.OS)

 	} else if runtime.GOOS != "windows" && unmarshalledConfig.OS == "windows" {

 		return nil, fmt.Errorf("image operating system %q cannot be used on this platform", unmarshalledConfig.OS)

@@ -2,26 +2,9 @@ package system

 import (

 	"os"

-	"syscall"

 	"time"

-	"unsafe"

 )

-var (

-	maxTime time.Time

-)

-

-func init() {

-	if unsafe.Sizeof(syscall.Timespec{}.Nsec) == 8 {

-		// This is a 64 bit timespec

-		// os.Chtimes limits time to the following

-		maxTime = time.Unix(0, 1<<63-1)

-	} else {

-		// This is a 32 bit timespec

-		maxTime = time.Unix(1<<31-1, 0)

-	}

-}

-

 // Chtimes changes the access time and modified time of a file at the given path

 func Chtimes(name string, atime time.Time, mtime time.Time) error {

 	unixMinTime := time.Unix(0, 0)

new file mode 100644

@@ -0,0 +1,22 @@

+package system

+

+import (

+	"syscall"

+	"time"

+	"unsafe"

+)

+

+// Used by chtimes

+var maxTime time.Time

+

+func init() {

+	// chtimes initialization

+	if unsafe.Sizeof(syscall.Timespec{}.Nsec) == 8 {

+		// This is a 64 bit timespec

+		// os.Chtimes limits time to the following

+		maxTime = time.Unix(0, 1<<63-1)

+	} else {

+		// This is a 32 bit timespec

+		maxTime = time.Unix(1<<31-1, 0)

+	}

+}

new file mode 100644

@@ -0,0 +1,17 @@

+package system

+

+import "os"

+

+// LCOWSupported determines if Linux Containers on Windows are supported.

+// Note: This feature is in development (06/17) and enabled through an

+// environment variable. At a future time, it will be enabled based

+// on build number. @jhowardmsft

+var lcowSupported = false

+

+func init() {

+	// LCOW initialization

+	if os.Getenv("LCOW_SUPPORTED") != "" {

+		lcowSupported = true

+	}

+

+}

new file mode 100644

@@ -0,0 +1,6 @@

+package system

+

+// LCOWSupported returns true if Linux containers on Windows are supported.

+func LCOWSupported() bool {

+	return lcowSupported

+}