diff --git a/arch/agat/encoder.cc b/arch/agat/encoder.cc
index b60d591c..4ece7bab 100644
--- a/arch/agat/encoder.cc
+++ b/arch/agat/encoder.cc
@@ -1,9 +1,9 @@
 #include "lib/core/globals.h"
+#include "lib/core/utils.h"
 #include "lib/decoders/decoders.h"
 #include "lib/encoders/encoders.h"
 #include "agat.h"
 #include "lib/core/crc.h"
-#include "lib/readerwriter.h"
 #include "lib/data/image.h"
 #include "lib/data/layout.h"
 #include "arch/agat/agat.pb.h"
diff --git a/arch/amiga/encoder.cc b/arch/amiga/encoder.cc
index bec5d82e..6a1f5bb1 100644
--- a/arch/amiga/encoder.cc
+++ b/arch/amiga/encoder.cc
@@ -1,9 +1,9 @@
 #include "lib/core/globals.h"
+#include "lib/core/utils.h"
 #include "lib/decoders/decoders.h"
 #include "lib/encoders/encoders.h"
 #include "amiga.h"
 #include "lib/core/crc.h"
-#include "lib/readerwriter.h"
 #include "lib/data/image.h"
 #include "arch/amiga/amiga.pb.h"
 #include "lib/encoders/encoders.pb.h"
diff --git a/arch/apple2/encoder.cc b/arch/apple2/encoder.cc
index 089f528e..24355939 100644
--- a/arch/apple2/encoder.cc
+++ b/arch/apple2/encoder.cc
@@ -1,9 +1,9 @@
 #include "lib/core/globals.h"
+#include "lib/core/utils.h"
 #include "arch/apple2/apple2.h"
 #include "lib/decoders/decoders.h"
 #include "lib/encoders/encoders.h"
 #include "lib/data/sector.h"
-#include "lib/readerwriter.h"
 #include "lib/data/image.h"
 #include "fmt/format.h"
 #include "lib/encoders/encoders.pb.h"
diff --git a/arch/brother/encoder.cc b/arch/brother/encoder.cc
index 188a27f6..f41cf98a 100644
--- a/arch/brother/encoder.cc
+++ b/arch/brother/encoder.cc
@@ -1,9 +1,9 @@
 #include "lib/core/globals.h"
+#include "lib/core/utils.h"
 #include "lib/decoders/decoders.h"
 #include "lib/encoders/encoders.h"
 #include "brother.h"
 #include "lib/core/crc.h"
-#include "lib/readerwriter.h"
 #include "lib/data/image.h"
 #include "arch/brother/brother.pb.h"
 #include "lib/encoders/encoders.pb.h"
diff --git a/arch/build.py b/arch/build.py
index f6ed5a7f..4fa9c2f9 100644
--- a/arch/build.py
+++ b/arch/build.py
@@ -98,5 +98,5 @@ cxxlibrary(
         "arch/tartu/tartu.h": "./tartu/tartu.h",
         "arch/arch.h": "./arch.h",
     },
-    deps=["+lib"],
+    deps=["lib/core", "lib/data", "lib/config", "lib/encoders", "lib/decoders"],
 )
diff --git a/arch/c64/encoder.cc b/arch/c64/encoder.cc
index ae0c0469..0bf45e0b 100644
--- a/arch/c64/encoder.cc
+++ b/arch/c64/encoder.cc
@@ -1,10 +1,10 @@
 #include "lib/core/globals.h"
+#include "lib/core/utils.h"
 #include "lib/decoders/decoders.h"
 #include "lib/encoders/encoders.h"
 #include "c64.h"
 #include "lib/core/crc.h"
 #include "lib/data/sector.h"
-#include "lib/readerwriter.h"
 #include "lib/data/image.h"
 #include "fmt/format.h"
 #include "arch/c64/c64.pb.h"
diff --git a/arch/ibm/encoder.cc b/arch/ibm/encoder.cc
index 2ad9c644..25c3496a 100644
--- a/arch/ibm/encoder.cc
+++ b/arch/ibm/encoder.cc
@@ -4,7 +4,6 @@
 #include "lib/encoders/encoders.h"
 #include "ibm.h"
 #include "lib/core/crc.h"
-#include "lib/readerwriter.h"
 #include "lib/data/image.h"
 #include "arch/ibm/ibm.pb.h"
 #include "lib/encoders/encoders.pb.h"
diff --git a/arch/macintosh/encoder.cc b/arch/macintosh/encoder.cc
index 50b6e6b7..75fd59a3 100644
--- a/arch/macintosh/encoder.cc
+++ b/arch/macintosh/encoder.cc
@@ -1,9 +1,9 @@
 #include "lib/core/globals.h"
+#include "lib/core/utils.h"
 #include "lib/decoders/decoders.h"
 #include "lib/encoders/encoders.h"
 #include "macintosh.h"
 #include "lib/core/crc.h"
-#include "lib/readerwriter.h"
 #include "lib/data/image.h"
 #include "fmt/format.h"
 #include "lib/encoders/encoders.pb.h"
diff --git a/arch/tids990/encoder.cc b/arch/tids990/encoder.cc
index f87d2b8b..0b78b99d 100644
--- a/arch/tids990/encoder.cc
+++ b/arch/tids990/encoder.cc
@@ -3,7 +3,6 @@
 #include "lib/encoders/encoders.h"
 #include "tids990.h"
 #include "lib/core/crc.h"
-#include "lib/readerwriter.h"
 #include "lib/data/image.h"
 #include "arch/tids990/tids990.pb.h"
 #include "lib/encoders/encoders.pb.h"
diff --git a/arch/victor9k/encoder.cc b/arch/victor9k/encoder.cc
index e5387ac3..683494c5 100644
--- a/arch/victor9k/encoder.cc
+++ b/arch/victor9k/encoder.cc
@@ -1,10 +1,10 @@
 #include "lib/core/globals.h"
+#include "lib/core/utils.h"
 #include "lib/decoders/decoders.h"
 #include "lib/encoders/encoders.h"
 #include "victor9k.h"
 #include "lib/core/crc.h"
 #include "lib/data/sector.h"
-#include "lib/readerwriter.h"
 #include "lib/data/image.h"
 #include "fmt/format.h"
 #include "arch/victor9k/victor9k.pb.h"
diff --git a/build.py b/build.py
index bb7c0c68..4d7fcc2c 100644
--- a/build.py
+++ b/build.py
@@ -22,11 +22,9 @@ clibrary(name="protocol", hdrs={"protocol.h": "./protocol.h"})
 cxxlibrary(
     name="lib",
     srcs=[
-        "./lib/encoders/encoders.cc",
         "./lib/readerwriter.cc",
     ],
     hdrs={
-        "lib/encoders/encoders.h": "./lib/encoders/encoders.h",
         "lib/readerwriter.h": "./lib/readerwriter.h",
     },
     deps=[
@@ -47,6 +45,7 @@ cxxlibrary(
         "lib/imagereader",
         "lib/imagewriter",
         "lib/decoders",
+        "lib/encoders",
     ],
 )
 
diff --git a/lib/core/utils.cc b/lib/core/utils.cc
index 812700e4..a63b1cec 100644
--- a/lib/core/utils.cc
+++ b/lib/core/utils.cc
@@ -249,3 +249,18 @@ void warning(const std::string msg)
 {
     log(msg);
 }
+
+void fillBitmapTo(std::vector<bool>& bitmap,
+    unsigned& cursor,
+    unsigned terminateAt,
+    const std::vector<bool>& pattern)
+{
+    while (cursor < terminateAt)
+    {
+        for (bool b : pattern)
+        {
+            if (cursor < bitmap.size())
+                bitmap[cursor++] = b;
+        }
+    }
+}
diff --git a/lib/core/utils.h b/lib/core/utils.h
index 89e87a9a..c5903ee4 100644
--- a/lib/core/utils.h
+++ b/lib/core/utils.h
@@ -23,6 +23,11 @@ extern int countSetBits(uint32_t word);
 extern uint32_t unbcd(uint32_t bcd);
 extern int findLowestSetBit(uint64_t value);
 
+extern void fillBitmapTo(std::vector<bool>& bitmap,
+    unsigned& cursor,
+    unsigned terminateAt,
+    const std::vector<bool>& pattern);
+
 template <class K, class V>
 std::map<V, K> reverseMap(const std::map<K, V>& map)
 {
diff --git a/lib/encoders/build.py b/lib/encoders/build.py
index 7972f9f6..fe7a8ba4 100644
--- a/lib/encoders/build.py
+++ b/lib/encoders/build.py
@@ -1,5 +1,5 @@
 from build.protobuf import proto, protocc
-
+from build.c import cxxlibrary
 
 proto(
     name="proto",
@@ -11,3 +11,10 @@ protocc(
     srcs=[".+proto"],
     deps=["lib+common_proto_lib", "arch+proto_lib"],
 )
+
+cxxlibrary(
+    name="encoders",
+    srcs=["./encoders.cc"],
+    hdrs={"lib/encoders/encoders.h": "./encoders.h"},
+    deps=["lib/core", "lib/data", "lib/config", ".+proto_lib"],
+)
diff --git a/lib/encoders/encoders.cc b/lib/encoders/encoders.cc
index 11d776b2..dd51e723 100644
--- a/lib/encoders/encoders.cc
+++ b/lib/encoders/encoders.cc
@@ -1,7 +1,6 @@
 #include "lib/core/globals.h"
 #include "lib/config/config.h"
 #include "lib/data/fluxmap.h"
-#include "lib/decoders/decoders.h"
 #include "lib/encoders/encoders.h"
 #include "lib/encoders/encoders.pb.h"
 #include "lib/config/proto.h"
diff --git a/lib/readerwriter.cc b/lib/readerwriter.cc
index a85aaea7..fc0bf839 100644
--- a/lib/readerwriter.cc
+++ b/lib/readerwriter.cc
@@ -768,18 +768,3 @@ void rawReadDiskCommand(FluxSource& fluxsource, FluxSink& fluxsink)
 
     log(EndOperationLogMessage{"Raw read complete"});
 }
-
-void fillBitmapTo(std::vector<bool>& bitmap,
-    unsigned& cursor,
-    unsigned terminateAt,
-    const std::vector<bool>& pattern)
-{
-    while (cursor < terminateAt)
-    {
-        for (bool b : pattern)
-        {
-            if (cursor < bitmap.size())
-                bitmap[cursor++] = b;
-        }
-    }
-}
diff --git a/lib/readerwriter.h b/lib/readerwriter.h
index 8295e740..3a2341e2 100644
--- a/lib/readerwriter.h
+++ b/lib/readerwriter.h
@@ -86,11 +86,6 @@ extern void writeTracksAndVerify(FluxSink& fluxSink,
     const Image& image,
     std::vector<std::shared_ptr<const TrackInfo>>& locations);
 
-extern void fillBitmapTo(std::vector<bool>& bitmap,
-    unsigned& cursor,
-    unsigned terminateAt,
-    const std::vector<bool>& pattern);
-
 extern void writeDiskCommand(const Image& image,
     Encoder& encoder,
     FluxSink& fluxSink,
diff --git a/src/fe-analysedriveresponse.cc b/src/fe-analysedriveresponse.cc
index 218af90d..52bfc14e 100644
--- a/src/fe-analysedriveresponse.cc
+++ b/src/fe-analysedriveresponse.cc
@@ -5,7 +5,6 @@
 #include "lib/core/bitmap.h"
 #include "lib/data/fluxmap.h"
 #include "lib/data/fluxmapreader.h"
-#include "lib/readerwriter.h"
 #include "protocol.h"
 #include "lib/config/proto.h"
 #include "lib/fluxsink/fluxsink.h"
diff --git a/src/fe-format.cc b/src/fe-format.cc
index c8440a08..1552c035 100644
--- a/src/fe-format.cc
+++ b/src/fe-format.cc
@@ -3,7 +3,6 @@
 #include "lib/data/fluxmap.h"
 #include "lib/data/sector.h"
 #include "lib/config/proto.h"
-#include "lib/readerwriter.h"
 #include "lib/imagereader/imagereader.h"
 #include "lib/imagewriter/imagewriter.h"
 #include "lib/fluxsource/fluxsource.h"
diff --git a/src/fe-getdiskinfo.cc b/src/fe-getdiskinfo.cc
index 28d890bb..2dc64b9f 100644
--- a/src/fe-getdiskinfo.cc
+++ b/src/fe-getdiskinfo.cc
@@ -3,7 +3,6 @@
 #include "lib/data/fluxmap.h"
 #include "lib/data/sector.h"
 #include "lib/config/proto.h"
-#include "lib/readerwriter.h"
 #include "lib/imagereader/imagereader.h"
 #include "lib/imagewriter/imagewriter.h"
 #include "lib/fluxsource/fluxsource.h"
diff --git a/src/fe-getfile.cc b/src/fe-getfile.cc
index bc4daf80..2a6ffd10 100644
--- a/src/fe-getfile.cc
+++ b/src/fe-getfile.cc
@@ -3,7 +3,6 @@
 #include "lib/data/fluxmap.h"
 #include "lib/data/sector.h"
 #include "lib/config/proto.h"
-#include "lib/readerwriter.h"
 #include "lib/imagereader/imagereader.h"
 #include "lib/imagewriter/imagewriter.h"
 #include "lib/fluxsource/fluxsource.h"
diff --git a/src/fe-getfileinfo.cc b/src/fe-getfileinfo.cc
index 801f5980..9b764a01 100644
--- a/src/fe-getfileinfo.cc
+++ b/src/fe-getfileinfo.cc
@@ -3,7 +3,6 @@
 #include "lib/data/fluxmap.h"
 #include "lib/data/sector.h"
 #include "lib/config/proto.h"
-#include "lib/readerwriter.h"
 #include "lib/imagereader/imagereader.h"
 #include "lib/imagewriter/imagewriter.h"
 #include "lib/fluxsource/fluxsource.h"
diff --git a/src/fe-inspect.cc b/src/fe-inspect.cc
index d024baae..d66cddc4 100644
--- a/src/fe-inspect.cc
+++ b/src/fe-inspect.cc
@@ -1,7 +1,6 @@
 #include "lib/core/globals.h"
 #include "lib/config/config.h"
 #include "lib/config/flags.h"
-#include "lib/readerwriter.h"
 #include "lib/data/fluxmap.h"
 #include "lib/data/fluxmapreader.h"
 #include "lib/decoders/fluxdecoder.h"
diff --git a/src/fe-ls.cc b/src/fe-ls.cc
index 0854cdb9..25e2a23b 100644
--- a/src/fe-ls.cc
+++ b/src/fe-ls.cc
@@ -3,7 +3,6 @@
 #include "lib/data/fluxmap.h"
 #include "lib/data/sector.h"
 #include "lib/config/proto.h"
-#include "lib/readerwriter.h"
 #include "lib/decoders/decoders.h"
 #include "lib/fluxsource/fluxsource.h"
 #include "lib/imagereader/imagereader.h"