diff --git a/Cargo.lock b/Cargo.lock
index 56bd823c1..14ebabb6e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -15,6 +15,7 @@ dependencies = [
  "ethsync 1.1.0",
  "fdlimit 0.1.0",
  "log 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "number_prefix 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "rpassword 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.18 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/Cargo.toml b/Cargo.toml
index e468799ea..f281cb854 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,6 +18,7 @@ time = "0.1"
 ctrlc = { git = "https://github.com/tomusdrw/rust-ctrlc.git" }
 fdlimit = { path = "util/fdlimit" }
 daemonize = "0.2"
+num_cpus = "0.2"
 number_prefix = "0.2"
 rpassword = "0.1"
 clippy = { version = "0.0.54", optional = true }
diff --git a/miner/src/lib.rs b/miner/src/lib.rs
index ca25e3993..06faf057e 100644
--- a/miner/src/lib.rs
+++ b/miner/src/lib.rs
@@ -65,7 +65,7 @@ pub use transaction_queue::{TransactionQueue, AccountDetails};
 pub use miner::{Miner};
 
 use std::sync::Mutex;
-use util::{H256, Address, Bytes};
+use util::{H256, Address, FixedHash, Bytes};
 use ethcore::client::{BlockChainClient};
 use ethcore::block::{ClosedBlock};
 use ethcore::error::{Error};
@@ -77,6 +77,12 @@ pub trait MinerService : Send + Sync {
 	/// Returns miner's status.
 	fn status(&self) -> MinerStatus;
 
+	/// Get the author that we will seal blocks as.
+	fn author(&self) -> Address { Address::zero() }
+
+	/// Get the extra_data that we will seal blocks wuth.
+	fn extra_data(&self) -> Bytes { vec![] }
+
 	/// Imports transactions to transaction queue.
 	fn import_transactions<T>(&self, transactions: Vec<SignedTransaction>, fetch_account: T) -> Vec<Result<(), Error>>
 		where T: Fn(&Address) -> AccountDetails;
diff --git a/miner/src/miner.rs b/miner/src/miner.rs
index e1b314d57..d4f6c8a00 100644
--- a/miner/src/miner.rs
+++ b/miner/src/miner.rs
@@ -146,6 +146,14 @@ impl MinerService for Miner {
 		}
 	}
 
+	fn author(&self) -> Address {
+		*self.author.read().unwrap()
+	}
+
+	fn extra_data(&self) -> Bytes {
+		self.extra_data.read().unwrap().clone()
+	}
+
 	fn import_transactions<T>(&self, transactions: Vec<SignedTransaction>, fetch_account: T) -> Vec<Result<(), Error>>
 		where T: Fn(&Address) -> AccountDetails {
 		let mut transaction_queue = self.transaction_queue.lock().unwrap();
diff --git a/parity/main.rs b/parity/main.rs
index 946e409bb..731bba9a1 100644
--- a/parity/main.rs
+++ b/parity/main.rs
@@ -20,6 +20,7 @@
 #![cfg_attr(feature="dev", feature(plugin))]
 #![cfg_attr(feature="dev", plugin(clippy))]
 extern crate docopt;
+extern crate num_cpus;
 extern crate rustc_serialize;
 extern crate ethcore_util as util;
 extern crate ethcore;
@@ -269,9 +270,7 @@ fn setup_rpc_server(
 			}
 		}
 	}
-	// 4 is the number of threads which also happens to be the maximum number of concurrent 
-	// connections our jsonrpc can manage.
-	Some(server.start_http(url, cors_domain, 4))
+	Some(server.start_http(url, cors_domain, ::num_cpus::get()))
 }
 
 #[cfg(not(feature = "rpc"))]
diff --git a/rpc/src/v1/impls/eth.rs b/rpc/src/v1/impls/eth.rs
index d7ee478bf..df21623fd 100644
--- a/rpc/src/v1/impls/eth.rs
+++ b/rpc/src/v1/impls/eth.rs
@@ -168,8 +168,8 @@ impl<C, S, A, M, EM> Eth for EthClient<C, S, A, M, EM>
 	// TODO: do not hardcode author.
 	fn author(&self, params: Params) -> Result<Value, Error> {
 		match params {
-			Params::None => to_value(&Address::new()),
-			_ => Err(Error::invalid_params())
+			Params::None => to_value(&take_weak!(self.miner).author()),
+			_ => Err(Error::invalid_params()),
 		}
 	}