diff --git a/arch/brother/brother.proto b/arch/brother/brother.proto
index f9d07f6a..9a314331 100644
--- a/arch/brother/brother.proto
+++ b/arch/brother/brother.proto
@@ -1,6 +1,8 @@
 syntax = "proto2";
 
-message Brother {
+message BrotherInput {}
+
+message BrotherOutput {
 	optional double clock_rate_us = 1 [default = 3.83];
 	optional double post_index_gap_ms = 2 [default = 1.0];
 	optional double sector_spacing_ms = 3 [default = 16.2];
diff --git a/arch/ibm/ibm.proto b/arch/ibm/ibm.proto
index 848042ed..17ba570a 100644
--- a/arch/ibm/ibm.proto
+++ b/arch/ibm/ibm.proto
@@ -1,6 +1,8 @@
 syntax = "proto2";
 
-message IBM {
+message IBMInput {}
+
+message IBMOutput {
 	enum FmMfm {
 		USE_MFM = 0;
 		USE_FM = 1;
diff --git a/lib/config.proto b/lib/config.proto
index 1c21b079..f3bdc687 100644
--- a/lib/config.proto
+++ b/lib/config.proto
@@ -8,28 +8,55 @@ import "google/protobuf/descriptor.proto";
 
 extend google.protobuf.FieldOptions {
   optional string help = 50000;
-  repeated string parameter = 50001;
-}
-
-message DiskEncoding {
-	optional int32 cylinder = 1;
-	optional int32 head = 2;
-	oneof format {
-		IBM ibm = 3;
-		Brother brother = 4;
-	}
-}
-
-message FileEncoding {
-	optional string filename = 1;
-	oneof format {
-		Img img = 2;
-	}
 }
 
 message Config {
-	repeated DiskEncoding disk = 2;
-	optional FileEncoding file = 3;
-	optional Decoder decoder = 4 [(help) = "Options for the flux decoder process"];
+	message InputFile {
+		optional string filename = 1;
+		oneof format {
+			ImgInputOutput img = 2;
+		}
+	}
+
+	message InputDisk {
+		optional int32 drive = 1;
+		oneof format {
+			IBMInput ibm = 2;
+			BrotherInput brother = 3;
+		}
+	}
+
+	message OutputFile {
+		optional string filename = 1;
+		oneof format {
+			ImgInputOutput img = 2;
+		}
+	}
+
+	message OutputDisk {
+		optional int32 drive = 1;
+		oneof format {
+			IBMOutput ibm = 2;
+			BrotherOutput brother = 3;
+		}
+	}
+
+	message Input {
+		oneof input {
+			InputFile file = 1;
+			InputDisk disk = 2;
+		}
+	}
+
+	message Output {
+		oneof output {
+			OutputFile file = 1;
+			OutputDisk disk = 2;
+		}
+	}
+
+	optional Input input = 1;
+	optional Output output = 2;
+	optional Decoder decoder = 3;
 }
 
diff --git a/lib/imagereader/img.proto b/lib/imagereader/img.proto
index 7d85059e..069e3611 100644
--- a/lib/imagereader/img.proto
+++ b/lib/imagereader/img.proto
@@ -1,6 +1,6 @@
 syntax = "proto2";
 
-message Img {
+message ImgInputOutput {
 	message Format {
 		optional int32 track = 1;
 		optional int32 side = 2;
diff --git a/tests/proto.cc b/tests/proto.cc
index 4d1539f2..133d4cf8 100644
--- a/tests/proto.cc
+++ b/tests/proto.cc
@@ -1,6 +1,7 @@
 #include "globals.h"
 #include "bytes.h"
 #include "tests/testproto.pb.h"
+#include "lib/config.pb.h"
 #include "proto.h"
 #include "snowhouse/snowhouse.h"
 #include <google/protobuf/text_format.h>
@@ -9,6 +10,14 @@
 
 using namespace snowhouse;
 
+static std::string cleanup(const std::string& s)
+{
+	auto outs = std::regex_replace(s, std::regex("[ \t\n]+"), " ");
+	outs = std::regex_replace(outs, std::regex("^[ \t\n]+"), "");
+	outs = std::regex_replace(outs, std::regex("[ \t\n]+$"), "");
+	return outs;
+}
+
 static void test_setting(void)
 {
 	TestProto config;
@@ -23,13 +32,40 @@ static void test_setting(void)
 
 	std::string s;
 	google::protobuf::TextFormat::PrintToString(config, &s);
-	s = std::regex_replace(s, std::regex("[ \t\n]+"), " ");
-	AssertThat(s, Equals("i64: -1 i32: -2 u64: 3 u32: 4 d: 5.5 m { s: \"string\" } r { s: \"val2\" } "));
+	s = cleanup(s);
+	AssertThat(s, Equals("i64: -1 i32: -2 u64: 3 u32: 4 d: 5.5 m { s: \"string\" } r { s: \"val2\" }"));
+}
+
+static void test_config(void)
+{
+	Config config;
+
+	const std::string text = R"M(
+		input {
+			file {
+				filename: "filename"
+			}
+		}
+
+		output {
+			disk {
+				drive: 0
+				ibm {
+				}
+			}
+		}
+	)M";
+	google::protobuf::TextFormat::MergeFromString(text, &config);
+
+	std::string s;
+	google::protobuf::TextFormat::PrintToString(config, &s);
+	AssertThat(cleanup(s), Equals(cleanup(text)));
 }
 
 int main(int argc, const char* argv[])
 {
 	test_setting();
+	test_config();
     return 0;
 }