diff --git a/src/ctx.cpp b/src/ctx.cpp
index d8783be8..b29f8b60 100644
--- a/src/ctx.cpp
+++ b/src/ctx.cpp
@@ -41,8 +41,6 @@ zmq::ctx_t::ctx_t (uint32_t io_threads_) :
     tag (0xbadcafe0),
     terminating (false)
 {
-    int rc;
-
     //  Initialise the array of mailboxes. Additional three slots are for
     //  internal log socket and the zmq_term thread the reaper thread.
     slot_count = max_sockets + io_threads_ + 3;
@@ -73,12 +71,6 @@ zmq::ctx_t::ctx_t (uint32_t io_threads_) :
         empty_slots.push_back (i);
         slots [i] = NULL;
     }
-
-    //  Create the logging infrastructure.
-    log_socket = create_socket (ZMQ_PUB);
-    zmq_assert (log_socket);
-    rc = log_socket->bind ("sys://log");
-    zmq_assert (rc == 0);
 }
 
 bool zmq::ctx_t::check_tag ()
@@ -122,14 +114,6 @@ int zmq::ctx_t::terminate ()
 
     //  First attempt to terminate the context.
     if (!restarted) {
-
-        //  Close the logging infrastructure.
-        log_sync.lock ();
-        int rc = log_socket->close ();
-        zmq_assert (rc == 0);
-        log_socket = NULL;
-        log_sync.unlock ();
-
         //  First send stop command to sockets so that any blocking calls can be
         //  interrupted. If there are no sockets we can ask reaper thread to stop.
         slot_sync.lock ();
@@ -302,24 +286,3 @@ zmq::endpoint_t zmq::ctx_t::find_endpoint (const char *addr_)
      endpoints_sync.unlock ();
      return *endpoint;
 }
-
-void zmq::ctx_t::log (const char *format_, va_list args_)
-{
-    //  Create the log message.
-    msg_t msg;
-    int rc = msg.init_size (strlen (format_) + 1);
-    errno_assert (rc == 0);
-    memcpy (msg.data (), format_, msg.size ());
-
-    //  At this  point we migrate the log socket to the current thread.
-    //  We rely on mutex for executing the memory barrier.
-    log_sync.lock ();
-    if (log_socket)
-        log_socket->send (&msg, 0);
-    log_sync.unlock ();
-
-    rc = msg.close ();
-    errno_assert (rc == 0);
-}
-
-
diff --git a/src/ctx.hpp b/src/ctx.hpp
index d259f594..9e345598 100644
--- a/src/ctx.hpp
+++ b/src/ctx.hpp
@@ -91,9 +91,6 @@ namespace zmq
         void unregister_endpoints (zmq::socket_base_t *socket_);
         endpoint_t find_endpoint (const char *addr_);
 
-        //  Logging.
-        void log (const char *format_, va_list args_);
-
         enum {
             term_tid = 0,
             reaper_tid = 1
@@ -146,11 +143,6 @@ namespace zmq
         //  Synchronisation of access to the list of inproc endpoints.
         mutex_t endpoints_sync;
 
-        //  PUB socket for logging. The socket is shared among all the threads,
-        //  thus it is synchronised by a mutex.
-        zmq::socket_base_t *log_socket;
-        mutex_t log_sync;
-
         ctx_t (const ctx_t&);
         const ctx_t &operator = (const ctx_t&);
     };
diff --git a/src/object.cpp b/src/object.cpp
index 622754cc..04044d39 100644
--- a/src/object.cpp
+++ b/src/object.cpp
@@ -149,14 +149,6 @@ void zmq::object_t::destroy_socket (socket_base_t *socket_)
     ctx->destroy_socket (socket_);
 }
 
-void zmq::object_t::log (const char *format_, ...)
-{
-    va_list args;
-    va_start (args, format_);
-    ctx->log (format_, args);
-    va_end (args);
-}
-
 zmq::io_thread_t *zmq::object_t::choose_io_thread (uint64_t affinity_)
 {
     return ctx->choose_io_thread (affinity_);
diff --git a/src/socket_base.cpp b/src/socket_base.cpp
index e3f10c0f..94906bc3 100644
--- a/src/socket_base.cpp
+++ b/src/socket_base.cpp
@@ -179,7 +179,7 @@ int zmq::socket_base_t::check_protocol (const std::string &protocol_)
 {
     //  First check out whether the protcol is something we are aware of.
     if (protocol_ != "inproc" && protocol_ != "ipc" && protocol_ != "tcp" &&
-          protocol_ != "pgm" && protocol_ != "epgm" && protocol_ != "sys") {
+          protocol_ != "pgm" && protocol_ != "epgm") {
         errno = EPROTONOSUPPORT;
         return -1;
     }
@@ -318,7 +318,7 @@ int zmq::socket_base_t::bind (const char *addr_)
     if (rc != 0)
         return -1;
 
-    if (protocol == "inproc" || protocol == "sys") {
+    if (protocol == "inproc") {
         endpoint_t endpoint = {this, options};
         return register_endpoint (addr_, endpoint);
     }
@@ -392,7 +392,7 @@ int zmq::socket_base_t::connect (const char *addr_)
     if (rc != 0)
         return -1;
 
-    if (protocol == "inproc" || protocol == "sys") {
+    if (protocol == "inproc") {
 
         //  TODO: inproc connect is specific with respect to creating pipes
         //  as there's no 'reconnect' functionality implemented. Once that