diff --git a/ChangeLog b/ChangeLog
index 5af03869..e44fe7dc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -12,6 +12,11 @@
 - better thread safety for vips8 operation dispatch
 - better thread safety for upstream / downstream image linking
 - added "rs" open mode, removed "rd"
+- added vips_operation_get_flags() ... system for attaching sets of flags to
+  operations
+- added VIPS_OPERATION_SEQUENTIAL flag
+- vips8 command-line interface uses this to turn sequential mode on
+  automatically when possible
 
 18/6/12 started 7.28.9
 - slightly more memory debugging output
diff --git a/TODO b/TODO
index a1a19b70..06c486a9 100644
--- a/TODO
+++ b/TODO
@@ -1,4 +1,3 @@
-
 - test "rs" mode
 
   can't see the code for "rd" mode?
diff --git a/libvips/arithmetic/arithmetic.c b/libvips/arithmetic/arithmetic.c
index 3fa79cd4..b746dccb 100644
--- a/libvips/arithmetic/arithmetic.c
+++ b/libvips/arithmetic/arithmetic.c
@@ -370,6 +370,7 @@ vips_arithmetic_class_init( VipsArithmeticClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	gobject_class->set_property = vips_object_set_property;
 	gobject_class->get_property = vips_object_get_property;
@@ -378,6 +379,8 @@ vips_arithmetic_class_init( VipsArithmeticClass *class )
 	vobject_class->description = _( "arithmetic operations" );
 	vobject_class->build = vips_arithmetic_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
 	VIPS_ARG_IMAGE( class, "out", 100, 
 		_( "Output" ), 
 		_( "Output image" ),
diff --git a/libvips/conversion/bandary.c b/libvips/conversion/bandary.c
index 673825ea..45bb4647 100644
--- a/libvips/conversion/bandary.c
+++ b/libvips/conversion/bandary.c
@@ -163,6 +163,7 @@ vips_bandary_class_init( VipsBandaryClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	VIPS_DEBUG_MSG( "vips_bandary_class_init\n" );
 
@@ -173,6 +174,7 @@ vips_bandary_class_init( VipsBandaryClass *class )
 	vobject_class->description = _( "operations on image bands" );
 	vobject_class->build = vips_bandary_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
 }
 
 static void
diff --git a/libvips/conversion/cast.c b/libvips/conversion/cast.c
index a18c2357..ee420694 100644
--- a/libvips/conversion/cast.c
+++ b/libvips/conversion/cast.c
@@ -462,6 +462,7 @@ vips_cast_class_init( VipsCastClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	VIPS_DEBUG_MSG( "vips_cast_class_init\n" );
 
@@ -472,6 +473,8 @@ vips_cast_class_init( VipsCastClass *class )
 	vobject_class->description = _( "cast an image" );
 	vobject_class->build = vips_cast_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
 	VIPS_ARG_IMAGE( class, "in", 1, 
 		_( "Input" ), 
 		_( "Input image" ),
diff --git a/libvips/conversion/copy.c b/libvips/conversion/copy.c
index 7570ef70..73927fd0 100644
--- a/libvips/conversion/copy.c
+++ b/libvips/conversion/copy.c
@@ -304,6 +304,7 @@ vips_copy_class_init( VipsCopyClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	VIPS_DEBUG_MSG( "vips_copy_class_init\n" );
 
@@ -314,6 +315,8 @@ vips_copy_class_init( VipsCopyClass *class )
 	vobject_class->description = _( "copy an image" );
 	vobject_class->build = vips_copy_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
 	VIPS_ARG_IMAGE( class, "in", 1, 
 		_( "Input" ), 
 		_( "Input image" ),
diff --git a/libvips/conversion/embed.c b/libvips/conversion/embed.c
index 1cf54d50..e90203a9 100644
--- a/libvips/conversion/embed.c
+++ b/libvips/conversion/embed.c
@@ -507,6 +507,7 @@ vips_embed_class_init( VipsEmbedClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	VIPS_DEBUG_MSG( "vips_embed_class_init\n" );
 
@@ -517,6 +518,8 @@ vips_embed_class_init( VipsEmbedClass *class )
 	vobject_class->description = _( "embed an image in a larger image" );
 	vobject_class->build = vips_embed_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
 	VIPS_ARG_IMAGE( class, "in", -1, 
 		_( "Input" ), 
 		_( "Input image" ),
diff --git a/libvips/conversion/extract.c b/libvips/conversion/extract.c
index 495c1005..d1b334e0 100644
--- a/libvips/conversion/extract.c
+++ b/libvips/conversion/extract.c
@@ -180,6 +180,7 @@ vips_extract_area_class_init( VipsExtractAreaClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	VIPS_DEBUG_MSG( "vips_extract_area_class_init\n" );
 
@@ -190,6 +191,8 @@ vips_extract_area_class_init( VipsExtractAreaClass *class )
 	vobject_class->description = _( "extract an area from an image" );
 	vobject_class->build = vips_extract_area_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
 	VIPS_ARG_IMAGE( class, "input", 0, 
 		_( "Input" ), 
 		_( "Input image" ),
diff --git a/libvips/conversion/flatten.c b/libvips/conversion/flatten.c
index 93946ddc..d4cd0461 100644
--- a/libvips/conversion/flatten.c
+++ b/libvips/conversion/flatten.c
@@ -358,6 +358,7 @@ vips_flatten_class_init( VipsFlattenClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	VIPS_DEBUG_MSG( "vips_flatten_class_init\n" );
 
@@ -368,6 +369,8 @@ vips_flatten_class_init( VipsFlattenClass *class )
 	vobject_class->description = _( "flatten alpha out of an image" );
 	vobject_class->build = vips_flatten_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
 	VIPS_ARG_IMAGE( class, "in", 1, 
 		_( "Input" ), 
 		_( "Input image" ),
diff --git a/libvips/conversion/ifthenelse.c b/libvips/conversion/ifthenelse.c
index e0756e33..e2ac66a2 100644
--- a/libvips/conversion/ifthenelse.c
+++ b/libvips/conversion/ifthenelse.c
@@ -458,6 +458,7 @@ vips_ifthenelse_class_init( VipsIfthenelseClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	VIPS_DEBUG_MSG( "vips_ifthenelse_class_init\n" );
 
@@ -468,6 +469,8 @@ vips_ifthenelse_class_init( VipsIfthenelseClass *class )
 	vobject_class->description = _( "ifthenelse an image" );
 	vobject_class->build = vips_ifthenelse_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
 	VIPS_ARG_IMAGE( class, "cond", -2, 
 		_( "Condition" ), 
 		_( "Condition input image" ),
diff --git a/libvips/conversion/insert.c b/libvips/conversion/insert.c
index 6b39c1cd..c100fa82 100644
--- a/libvips/conversion/insert.c
+++ b/libvips/conversion/insert.c
@@ -339,6 +339,7 @@ vips_insert_class_init( VipsInsertClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	VIPS_DEBUG_MSG( "vips_insert_class_init\n" );
 
@@ -349,6 +350,8 @@ vips_insert_class_init( VipsInsertClass *class )
 	vobject_class->description = _( "insert an image" );
 	vobject_class->build = vips_insert_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
 	VIPS_ARG_IMAGE( class, "main", -1, 
 		_( "Main" ), 
 		_( "Main input image" ),
diff --git a/libvips/conversion/join.c b/libvips/conversion/join.c
index 815f4ccb..bcc6e307 100644
--- a/libvips/conversion/join.c
+++ b/libvips/conversion/join.c
@@ -200,6 +200,7 @@ vips_join_class_init( VipsJoinClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	VIPS_DEBUG_MSG( "vips_join_class_init\n" );
 
@@ -210,6 +211,8 @@ vips_join_class_init( VipsJoinClass *class )
 	vobject_class->description = _( "join a pair of images" );
 	vobject_class->build = vips_join_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
 	VIPS_ARG_IMAGE( class, "in1", -1, 
 		_( "in1" ), 
 		_( "First input image" ),
diff --git a/libvips/conversion/recomb.c b/libvips/conversion/recomb.c
index 6d1b7ce8..197674ea 100644
--- a/libvips/conversion/recomb.c
+++ b/libvips/conversion/recomb.c
@@ -188,6 +188,7 @@ vips_recomb_class_init( VipsRecombClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *object_class = (VipsObjectClass *) class;
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	gobject_class->set_property = vips_object_set_property;
 	gobject_class->get_property = vips_object_get_property;
@@ -196,6 +197,8 @@ vips_recomb_class_init( VipsRecombClass *class )
 	object_class->description = _( "linear recombination with matrix" );
 	object_class->build = vips_recomb_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
 	VIPS_ARG_IMAGE( class, "in", 0, 
 		_( "Input" ), 
 		_( "Input image argument" ),
diff --git a/libvips/foreign/foreign.c b/libvips/foreign/foreign.c
index 1ca49054..7787b017 100644
--- a/libvips/foreign/foreign.c
+++ b/libvips/foreign/foreign.c
@@ -702,7 +702,7 @@ vips_foreign_load_temp( VipsForeignLoad *load )
 
 		/* You can't reuse sequential operations.
 		 */
-		vips_operation_set_nocache( VIPS_OPERATION( load ), TRUE );
+		load->nocache = TRUE;
 
 		return( vips_image_new() );
 	}
@@ -889,11 +889,26 @@ vips_foreign_load_build( VipsObject *object )
 	return( 0 );
 }
 
+static VipsOperationFlags 
+vips_foreign_load_real_get_flags( VipsOperation *operation )
+{
+	VipsForeignLoad *load = VIPS_FOREIGN_LOAD( operation );
+	VipsOperationFlags flags;
+
+	flags = VIPS_OPERATION_CLASS( vips_foreign_load_parent_class )->
+		get_flags( operation );
+	if( load->nocache )
+		flags |= VIPS_OPERATION_NOCACHE;
+
+	return( flags );
+}
+
 static void
 vips_foreign_load_class_init( VipsForeignLoadClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *object_class = (VipsObjectClass *) class;
+	VipsOperationClass *operation_class = (VipsOperationClass *) class;
 
 	gobject_class->dispose = vips_foreign_load_dispose;
 	gobject_class->set_property = vips_object_set_property;
@@ -905,6 +920,8 @@ vips_foreign_load_class_init( VipsForeignLoadClass *class )
 	object_class->nickname = "fileload";
 	object_class->description = _( "file loaders" );
 
+	operation_class->get_flags = vips_foreign_load_real_get_flags;
+
 	VIPS_ARG_IMAGE( class, "out", 2, 
 		_( "Output" ), 
 		_( "Output image" ),
diff --git a/libvips/include/vips/Makefile.am b/libvips/include/vips/Makefile.am
index ed64a858..138c57a4 100644
--- a/libvips/include/vips/Makefile.am
+++ b/libvips/include/vips/Makefile.am
@@ -63,6 +63,7 @@ vips_scan_headers = \
 	${top_srcdir}/libvips/include/vips/conversion.h \
 	${top_srcdir}/libvips/include/vips/util.h \
 	${top_srcdir}/libvips/include/vips/image.h \
+	${top_srcdir}/libvips/include/vips/operation.h \
 	${top_srcdir}/libvips/include/vips/object.h
 
 enumtypes.h: $(vips_scan_headers) Makefile
diff --git a/libvips/include/vips/enumtypes.h b/libvips/include/vips/enumtypes.h
index e313bd2e..44bc558d 100644
--- a/libvips/include/vips/enumtypes.h
+++ b/libvips/include/vips/enumtypes.h
@@ -57,6 +57,9 @@ GType vips_band_format_get_type (void) G_GNUC_CONST;
 #define VIPS_TYPE_BAND_FORMAT (vips_band_format_get_type())
 GType vips_coding_get_type (void) G_GNUC_CONST;
 #define VIPS_TYPE_CODING (vips_coding_get_type())
+/* enumerations from "../../../libvips/include/vips/operation.h" */
+GType vips_operation_flags_get_type (void) G_GNUC_CONST;
+#define VIPS_TYPE_OPERATION_FLAGS (vips_operation_flags_get_type())
 /* enumerations from "../../../libvips/include/vips/object.h" */
 GType vips_argument_flags_get_type (void) G_GNUC_CONST;
 #define VIPS_TYPE_ARGUMENT_FLAGS (vips_argument_flags_get_type())
diff --git a/libvips/include/vips/foreign.h b/libvips/include/vips/foreign.h
index a1d42e40..cbe30807 100644
--- a/libvips/include/vips/foreign.h
+++ b/libvips/include/vips/foreign.h
@@ -136,6 +136,10 @@ typedef struct _VipsForeignLoad {
 	 * disc foreign or a memory buffer. This must be set by ->load().
 	 */
 	VipsImage *real;
+
+	/* Set this to tag the operation as nocache.
+	 */
+	gboolean nocache;
 } VipsForeignLoad;
 
 typedef struct _VipsForeignLoadClass {
diff --git a/libvips/include/vips/operation.h b/libvips/include/vips/operation.h
index bae34ae6..8689dcc2 100644
--- a/libvips/include/vips/operation.h
+++ b/libvips/include/vips/operation.h
@@ -36,6 +36,27 @@ extern "C" {
 
 #include <vips/vips.h>
 
+/** 
+ * VipsOperationFlags:
+ * @VIPS_OPERATION_NONE: no flags
+ * @VIPS_OPERATION_SEQUENTIAL: can work sequentially
+ * @VIPS_OPERATION_NOCACHE: must not be cached
+ *
+ * Flags we associate with an operation.
+ *
+ * @VIPS_OPERATION_SEQUENTIAL means that the operation works like vips_copy:
+ * it can happily process images top-to-bottom with only small non-local
+ * references.
+ *
+ * @VIPS_OPERATION_NOCACHE means that the operation must not be cached by
+ * vips. 
+ */
+typedef enum /*< flags >*/ {
+	VIPS_OPERATION_NONE = 0,
+	VIPS_OPERATION_SEQUENTIAL = 1,
+	VIPS_OPERATION_NOCACHE = 2
+} VipsOperationFlags;
+
 #define VIPS_TYPE_OPERATION (vips_operation_get_type())
 #define VIPS_OPERATION( obj ) \
 	(G_TYPE_CHECK_INSTANCE_CAST( (obj), \
@@ -66,12 +87,6 @@ typedef struct _VipsOperation {
 	guint hash;
 	gboolean found_hash;
 
-	/* Set this before the end of _build() to stop this operation from 
-	 * being cached. Some things, like sequential read from a TIFF file, 
-	 * can't be reused.
-	 */
-	gboolean nocache;
-
 } VipsOperation;
 
 typedef struct _VipsOperationClass {
@@ -80,10 +95,17 @@ typedef struct _VipsOperationClass {
 	/* Print the usage message.
 	 */
 	void (*usage)( struct _VipsOperationClass *, VipsBuf * );
+
+	/* Return a set of operation flags. If @get_flags is NULL, just use
+	 * flags.
+	 */
+	VipsOperationFlags (*get_flags)( VipsOperation * ); 
+	VipsOperationFlags flags;
 } VipsOperationClass;
 
 GType vips_operation_get_type( void );
 
+VipsOperationFlags vips_operation_get_flags( VipsOperation *operation );
 void vips_operation_class_print_usage( VipsOperationClass *operation_class );
 
 int vips_operation_call_valist( VipsOperation *operation, va_list ap );
@@ -96,7 +118,6 @@ void vips_call_options( GOptionGroup *group, VipsOperation *operation );
 int vips_call_argv( VipsOperation *operation, int argc, char **argv );
 
 void vips_cache_drop_all( void );
-void vips_operation_set_nocache( VipsOperation *operation, gboolean nocache );
 int vips_cache_operation_buildp( VipsOperation **operation );
 VipsOperation *vips_cache_operation_build( VipsOperation *operation );
 void vips_cache_print( void );
diff --git a/libvips/iofuncs/Makefile.am b/libvips/iofuncs/Makefile.am
index 0d538ae4..3c9cca3e 100644
--- a/libvips/iofuncs/Makefile.am
+++ b/libvips/iofuncs/Makefile.am
@@ -46,6 +46,7 @@ vips_scan_headers = \
 	${top_srcdir}/libvips/include/vips/arithmetic.h \
 	${top_srcdir}/libvips/include/vips/util.h \
 	${top_srcdir}/libvips/include/vips/image.h \
+	${top_srcdir}/libvips/include/vips/operation.h \
 	${top_srcdir}/libvips/include/vips/object.h
 
 enumtypes.c: $(vips_scan_headers) Makefile
diff --git a/libvips/iofuncs/cache.c b/libvips/iofuncs/cache.c
index 920b3591..55273763 100644
--- a/libvips/iofuncs/cache.c
+++ b/libvips/iofuncs/cache.c
@@ -693,7 +693,8 @@ vips_cache_operation_buildp( VipsOperation **operation )
 
 	if( !hit ) {
 		if( vips__cache_trace ) {
-			if( (*operation)->nocache ) 
+			if( vips_operation_get_flags( *operation ) & 
+				VIPS_OPERATION_NOCACHE )
 				printf( "vips cache: uncacheable %p\n  ", 
 					*operation );
 			else
@@ -706,7 +707,8 @@ vips_cache_operation_buildp( VipsOperation **operation )
 
 		g_mutex_lock( vips_cache_lock );
 
-		if( !(*operation)->nocache ) {
+		if( !(vips_operation_get_flags( *operation ) & 
+			VIPS_OPERATION_NOCACHE) ) {
 			vips_cache_ref( *operation );
 			g_hash_table_insert( vips_cache_table, 
 				*operation, *operation );
diff --git a/libvips/iofuncs/enumtypes.c b/libvips/iofuncs/enumtypes.c
index c8eb8554..676d279b 100644
--- a/libvips/iofuncs/enumtypes.c
+++ b/libvips/iofuncs/enumtypes.c
@@ -492,6 +492,25 @@ vips_coding_get_type( void )
 
 	return( etype );
 }
+/* enumerations from "../../libvips/include/vips/operation.h" */
+GType
+vips_operation_flags_get_type( void )
+{
+	static GType etype = 0;
+
+	if( etype == 0 ) {
+		static const GFlagsValue values[] = {
+			{VIPS_OPERATION_NONE, "VIPS_OPERATION_NONE", "none"},
+			{VIPS_OPERATION_SEQUENTIAL, "VIPS_OPERATION_SEQUENTIAL", "sequential"},
+			{VIPS_OPERATION_NOCACHE, "VIPS_OPERATION_NOCACHE", "nocache"},
+			{0, NULL, NULL}
+		};
+		
+		etype = g_flags_register_static( "VipsOperationFlags", values );
+	}
+
+	return( etype );
+}
 /* enumerations from "../../libvips/include/vips/object.h" */
 GType
 vips_argument_flags_get_type( void )
diff --git a/libvips/iofuncs/object.c b/libvips/iofuncs/object.c
index d809fe48..1c27fde7 100644
--- a/libvips/iofuncs/object.c
+++ b/libvips/iofuncs/object.c
@@ -1466,12 +1466,27 @@ vips_object_set_argument_from_string( VipsObject *object,
 
 	if( g_type_is_a( otype, VIPS_TYPE_IMAGE ) ) { 
 		VipsImage *out;
+		VipsOperationFlags flags;
+
+		flags = 0;
+		if( VIPS_IS_OPERATION( object ) )
+			flags = vips_operation_get_flags( 
+				VIPS_OPERATION( object ) );
 
 		/* Read the filename. vips_foreign_load_options()
 		 * handles embedded options.
 		 */
-		if( vips_foreign_load_options( value, &out, NULL ) )
-			return( -1 );
+		if( flags & VIPS_OPERATION_SEQUENTIAL ) {
+			if( vips_foreign_load_options( value, &out, 
+				"sequential", TRUE,
+				NULL ) )
+				return( -1 );
+		}
+		else {
+			if( vips_foreign_load_options( value, &out, 
+				NULL ) )
+				return( -1 );
+		}
 
 		g_value_init( &gvalue, VIPS_TYPE_IMAGE );
 		g_value_set_object( &gvalue, out );
diff --git a/libvips/iofuncs/operation.c b/libvips/iofuncs/operation.c
index 7c6cda0d..e74e8d33 100644
--- a/libvips/iofuncs/operation.c
+++ b/libvips/iofuncs/operation.c
@@ -148,6 +148,24 @@ vips_operation_usage( VipsOperationClass *class, VipsBuf *buf )
 	vips_argument_class_map( object_class,
 		(VipsArgumentClassMapFn) vips_operation_class_usage_arg, 
 			buf, &usage );
+
+	/* Show flags.
+	 */
+	if( class->flags ) {
+		GFlagsValue *value;
+		VipsOperationFlags flags;
+		GFlagsClass *flags_class = 
+			g_type_class_ref( VIPS_TYPE_OPERATION_FLAGS );
+
+		vips_buf_appendf( buf, "operation flags: " );
+		flags = class->flags; 
+		while( flags && (value = 
+			g_flags_get_first_value( flags_class, flags )) ) {
+			vips_buf_appendf( buf, "%s ", value->value_nick );
+			flags &= ~value->value;
+		}
+		vips_buf_appends( buf, "\n" );
+	}
 }
 
 static void *
@@ -233,6 +251,14 @@ vips_operation_summary( VipsObject *object, VipsBuf *buf )
 		summary( object, buf );
 }
 
+static VipsOperationFlags
+vips_operation_real_get_flags( VipsOperation *operation ) 
+{
+	VipsOperationClass *class = VIPS_OPERATION_GET_CLASS( operation );
+
+	return( class->flags );
+}
+
 static void
 vips_operation_class_init( VipsOperationClass *class )
 {
@@ -248,6 +274,7 @@ vips_operation_class_init( VipsOperationClass *class )
 	vobject_class->dump = vips_operation_dump;
 
 	class->usage = vips_operation_usage;
+	class->get_flags = vips_operation_real_get_flags;
 }
 
 static void
@@ -257,6 +284,22 @@ vips_operation_init( VipsOperation *operation )
 	 */
 }
 
+/**
+ * vips_operation_get_flags:
+ * @operation: operation to fetch flags from
+ *
+ * Returns the set of flags for this operation.
+ *
+ * Returns: 0 on success, or -1 on error.
+ */
+VipsOperationFlags
+vips_operation_get_flags( VipsOperation *operation ) 
+{
+	VipsOperationClass *class = VIPS_OPERATION_GET_CLASS( operation );
+
+	return( class->get_flags( operation ) );
+}
+
 /**
  * vips_operation_class_print_usage: (skip)
  * @operation_class: class to print usage for
@@ -913,24 +956,3 @@ vips_call_argv( VipsOperation *operation, int argc, char **argv )
 
 	return( 0 );
 }
-
-/**
- * vips_operation_set_nocache: 
- * @operation: operation to set
- * @nocache: TRUE means don't cache this operation
- *
- * Set this before the end of _build() to stop this operation being cached.
- * Some operations, like sequential read from a TIFF file, for example, cannot
- * be reused.
- */
-void 
-vips_operation_set_nocache( VipsOperation *operation, gboolean nocache )
-{
-#ifdef VIPS_DEBUG
-	printf( "vips_operation_set_nocache: " );
-	vips_object_print_name( VIPS_OBJECT( operation ) );
-	printf( " %d\n", nocache );
-#endif /*VIPS_DEBUG*/
-
-	operation->nocache = nocache;
-}
diff --git a/libvips/resample/shrink.c b/libvips/resample/shrink.c
index f038c28d..747bdd6b 100644
--- a/libvips/resample/shrink.c
+++ b/libvips/resample/shrink.c
@@ -360,6 +360,7 @@ vips_shrink_class_init( VipsShrinkClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	VIPS_DEBUG_MSG( "vips_shrink_class_init\n" );
 
@@ -370,6 +371,8 @@ vips_shrink_class_init( VipsShrinkClass *class )
 	vobject_class->description = _( "shrink an image" );
 	vobject_class->build = vips_shrink_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
 	VIPS_ARG_DOUBLE( class, "xshrink", 8, 
 		_( "Xshrink" ), 
 		_( "Horizontal shrink factor" ),