uint32_t new_VolSessionId();
/* From acquire.c */
-int acquire_device_for_append(JCR *jcr, DEVICE *dev, DEV_BLOCK *block);
+DEVICE *acquire_device_for_append(JCR *jcr, DEVICE *dev, DEV_BLOCK *block);
int acquire_device_for_read(JCR *jcr, DEVICE *dev, DEV_BLOCK *block);
int release_device(JCR *jcr, DEVICE *dev);