diff --git a/Makefile.in b/Makefile.in
index 365416a..ea0c943 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -353,6 +353,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
@@ -583,7 +584,7 @@ distdir: $(DISTFILES)
 	  ! -type d ! -perm -444 -exec $(install_sh) -c -m a+r {} {} \; \
 	|| chmod -R a+r "$(distdir)"
 dist-gzip: distdir
-	tardir=$(distdir) && $(am__tar) | eval GZIP= gzip $(GZIP_ENV) -c >$(distdir).tar.gz
+	tardir=$(distdir) && $(am__tar) | GZIP=$(GZIP_ENV) gzip -c >$(distdir).tar.gz
 	$(am__post_remove_distdir)
 
 dist-bzip2: distdir
@@ -609,7 +610,7 @@ dist-shar: distdir
 	@echo WARNING: "Support for shar distribution archives is" \
 	               "deprecated." >&2
 	@echo WARNING: "It will be removed altogether in Automake 2.0" >&2
-	shar $(distdir) | eval GZIP= gzip $(GZIP_ENV) -c >$(distdir).shar.gz
+	shar $(distdir) | GZIP=$(GZIP_ENV) gzip -c >$(distdir).shar.gz
 	$(am__post_remove_distdir)
 
 dist-zip: distdir
@@ -627,7 +628,7 @@ dist dist-all:
 distcheck: dist
 	case '$(DIST_ARCHIVES)' in \
 	*.tar.gz*) \
-	  eval GZIP= gzip $(GZIP_ENV) -dc $(distdir).tar.gz | $(am__untar) ;;\
+	  GZIP=$(GZIP_ENV) gzip -dc $(distdir).tar.gz | $(am__untar) ;;\
 	*.tar.bz2*) \
 	  bzip2 -dc $(distdir).tar.bz2 | $(am__untar) ;;\
 	*.tar.lz*) \
@@ -637,7 +638,7 @@ distcheck: dist
 	*.tar.Z*) \
 	  uncompress -c $(distdir).tar.Z | $(am__untar) ;;\
 	*.shar.gz*) \
-	  eval GZIP= gzip $(GZIP_ENV) -dc $(distdir).shar.gz | unshar ;;\
+	  GZIP=$(GZIP_ENV) gzip -dc $(distdir).shar.gz | unshar ;;\
 	*.zip*) \
 	  unzip $(distdir).zip ;;\
 	esac
diff --git a/configure b/configure
index 5d4ee94..5209704 100755
--- a/configure
+++ b/configure
@@ -779,6 +779,7 @@ infodir
 docdir
 oldincludedir
 includedir
+runstatedir
 localstatedir
 sharedstatedir
 sysconfdir
@@ -871,6 +872,7 @@ datadir='${datarootdir}'
 sysconfdir='${prefix}/etc'
 sharedstatedir='${prefix}/com'
 localstatedir='${prefix}/var'
+runstatedir='${localstatedir}/run'
 includedir='${prefix}/include'
 oldincludedir='/usr/include'
 docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
@@ -1123,6 +1125,15 @@ do
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;
 
+  -runstatedir | --runstatedir | --runstatedi | --runstated \
+  | --runstate | --runstat | --runsta | --runst | --runs \
+  | --run | --ru | --r)
+    ac_prev=runstatedir ;;
+  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
+  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
+  | --run=* | --ru=* | --r=*)
+    runstatedir=$ac_optarg ;;
+
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1260,7 +1271,7 @@ fi
 for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
 		datadir sysconfdir sharedstatedir localstatedir includedir \
 		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-		libdir localedir mandir
+		libdir localedir mandir runstatedir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -1413,6 +1424,7 @@ Fine tuning of the installation directories:
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
+  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
diff --git a/lib/Makefile.in b/lib/Makefile.in
index 9ddb705..349b897 100644
--- a/lib/Makefile.in
+++ b/lib/Makefile.in
@@ -400,6 +400,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
diff --git a/lib/hcl-s.c b/lib/hcl-s.c
index 257eca0..19fca6a 100644
--- a/lib/hcl-s.c
+++ b/lib/hcl-s.c
@@ -222,6 +222,8 @@ typedef enum hcl_server_worker_state_t hcl_server_worker_state_t;
 struct hcl_server_worker_t
 {
 	pthread_t thr;
+	hcl_oow_t wid;
+
 	int sck;
 	/* TODO: peer address */
 
@@ -236,6 +238,13 @@ struct hcl_server_worker_t
 	hcl_server_worker_t* next_worker;
 };
 
+union hcl_server_wid_map_data_t
+{
+	hcl_server_worker_t* worker;
+	hcl_oow_t            next;
+};
+typedef union hcl_server_wid_map_data_t hcl_server_wid_map_data_t;
+		
 struct hcl_server_t
 {
 	hcl_mmgr_t*  mmgr;
@@ -268,6 +277,14 @@ struct hcl_server_t
 		hcl_server_worker_t* tail;
 	} worker_list[2];
 
+	struct
+	{
+		hcl_server_wid_map_data_t* ptr;
+		hcl_oow_t                  capa;
+		hcl_oow_t                  free_first;
+		hcl_oow_t                  free_last;
+	} wid_map;
+
 	int mux_pipe[2]; /* pipe to break the blocking multiplexer in the main server loop */
 
 	pthread_mutex_t worker_mutex;
@@ -588,7 +605,7 @@ static void log_write (hcl_t* hcl, unsigned int mask, const hcl_ooch_t* msg, hcl
 
 	server = xtn->proto->worker->server;
 	pthread_mutex_lock (&server->log_mutex);
-	server->prim.log_write (server, xtn->proto->worker->sck, mask, msg, len);
+	server->prim.log_write (server, xtn->proto->worker->wid, mask, msg, len);
 	pthread_mutex_unlock (&server->log_mutex);
 }
 
@@ -599,7 +616,7 @@ static void log_write_for_dummy (hcl_t* hcl, unsigned int mask, const hcl_ooch_t
 
 	server = xtn->server;
 	pthread_mutex_lock (&server->log_mutex);
-	server->prim.log_write (server, -1, mask, msg, len);
+	server->prim.log_write (server, HCL_SERVER_WID_INVALID, mask, msg, len);
 	pthread_mutex_unlock (&server->log_mutex);
 }
 
@@ -1711,6 +1728,9 @@ hcl_server_t* hcl_server_open (hcl_mmgr_t* mmgr, hcl_oow_t xtnsize, hcl_server_p
 	server->mux_pipe[0] = pfd[0];
 	server->mux_pipe[1] = pfd[1];
 
+	server->wid_map.free_first = HCL_SERVER_WID_INVALID;
+	server->wid_map.free_last = HCL_SERVER_WID_INVALID;
+	
 	pthread_mutex_init (&server->worker_mutex, HCL_NULL);
 	pthread_mutex_init (&server->tmr_mutex, HCL_NULL);
 	pthread_mutex_init (&server->log_mutex, HCL_NULL);
@@ -1732,6 +1752,14 @@ hcl_server_t* hcl_server_open (hcl_mmgr_t* mmgr, hcl_oow_t xtnsize, hcl_server_p
 
 void hcl_server_close (hcl_server_t* server)
 {
+	if (server->wid_map.ptr)
+	{
+		HCL_MMGR_FREE (server->mmgr, server->wid_map.ptr);
+		server->wid_map.capa = 0;
+		server->wid_map.free_first = HCL_SERVER_WID_INVALID;
+		server->wid_map.free_last = HCL_SERVER_WID_INVALID;
+	}
+	
 	pthread_mutex_destroy (&server->log_mutex);
 	pthread_mutex_destroy (&server->tmr_mutex);
 	pthread_mutex_destroy (&server->worker_mutex);
@@ -1743,17 +1771,105 @@ void hcl_server_close (hcl_server_t* server)
 	HCL_MMGR_FREE (server->mmgr, server);
 }
 
-static hcl_server_worker_t* alloc_worker (hcl_server_t*  server, int cli_sck)
+static HCL_INLINE int prepare_to_acquire_wid (hcl_server_t* server)
+{
+	hcl_oow_t new_capa;
+	hcl_ooi_t i, j;
+	hcl_server_wid_map_data_t* tmp;
+
+	HCL_ASSERT (server->dummy_hcl, server->wid_map.free_first == HCL_SERVER_WID_INVALID);
+	HCL_ASSERT (server->dummy_hcl, server->wid_map.free_last == HCL_SERVER_WID_INVALID);
+
+	new_capa = server->wid_map.capa + 128; /* TODO: adjust this incremental size ? */
+	if (new_capa > HCL_SERVER_WID_MAX)
+	{
+		if (server->wid_map.capa >= HCL_SERVER_WID_MAX)
+		{
+			/* too many workers??? */
+			/* TODO: error handling */
+			//hcl_seterrbfmt (hcl, HCL_EPFULL, "maximum number(%zd) of processes reached", HCL_SMOOI_MAX);
+printf ("too many workers??? \n");
+			return -1;
+		}
+
+		new_capa = HCL_SERVER_WID_MAX;
+	}
+
+	tmp = (hcl_server_wid_map_data_t*)HCL_MMGR_REALLOC(server->mmgr, server->wid_map.ptr, HCL_SIZEOF(*tmp) * new_capa);
+	if (!tmp) 
+	{
+// TODO: error handling ....
+printf ("cannot reallocate wid map...\n");
+		return -1;
+	}
+
+	server->wid_map.free_first = server->wid_map.capa;
+	for (i = server->wid_map.capa, j = server->wid_map.capa + 1; j < new_capa; i++, j++)
+	{
+		tmp[i].next = j;
+	}
+	tmp[i].next = HCL_SERVER_WID_INVALID;
+	server->wid_map.free_last = i;
+
+	server->wid_map.ptr = tmp;
+	server->wid_map.capa = new_capa;
+
+	return 0;
+}
+
+static HCL_INLINE void acquire_wid (hcl_server_t* server, hcl_server_worker_t* worker)
+{
+	hcl_oow_t wid;
+
+	wid = server->wid_map.free_first;
+	worker->wid = wid;
+
+	server->wid_map.free_first = server->wid_map.ptr[wid].next;
+	if (server->wid_map.free_first == HCL_SERVER_WID_INVALID) server->wid_map.free_last = HCL_SERVER_WID_INVALID;
+
+	server->wid_map.ptr[wid].worker = worker;
+}
+
+static HCL_INLINE void release_wid (hcl_server_t* server, hcl_server_worker_t* worker)
+{
+	hcl_oow_t wid;
+
+	wid = worker->wid;
+	HCL_ASSERT (server->dummy_hcl, wid < server->wid_map.capa && wid != HCL_SERVER_WID_INVALID);
+
+	server->wid_map.ptr[wid].next = HCL_SERVER_WID_INVALID;
+	if (server->wid_map.free_last == HCL_SERVER_WID_INVALID)
+	{
+		HCL_ASSERT (server->dummy_hcl, server->wid_map.free_first <= HCL_SERVER_WID_INVALID);
+		server->wid_map.free_first = wid;
+	}
+	else
+	{
+		server->wid_map.ptr[server->wid_map.free_last].next = wid;
+	}
+	server->wid_map.free_last = wid;
+	worker->wid = HCL_SERVER_WID_INVALID;
+}
+
+
+static hcl_server_worker_t* alloc_worker (hcl_server_t* server, int cli_sck)
 {
 	hcl_server_worker_t* worker;
 
-	worker = (hcl_server_worker_t*)HCL_MMGR_ALLOC (server->mmgr, HCL_SIZEOF(*worker));
+	worker = (hcl_server_worker_t*)HCL_MMGR_ALLOC(server->mmgr, HCL_SIZEOF(*worker));
 	if (!worker) return HCL_NULL;
 
 	HCL_MEMSET (worker, 0, HCL_SIZEOF(*worker));
 	worker->sck = cli_sck;
 	worker->server = server;
-/* TODO: allocate a unique id for worker. the socket number isn't very nice because once  it's closed, the uniqueness can't be guaranteed */
+
+	if (server->wid_map.free_first == HCL_SERVER_WID_INVALID && prepare_to_acquire_wid(server) <= -1) 
+	{
+		HCL_MMGR_FREE (server->mmgr, worker);
+		return HCL_NULL;
+	}
+
+	acquire_wid (server, worker);
 	return worker;
 }
 
@@ -1777,6 +1893,7 @@ static void close_worker_socket (hcl_server_worker_t* worker)
 static void free_worker (hcl_server_worker_t* worker)
 {
 	close_worker_socket (worker);
+	release_wid (worker->server, worker);
 	HCL_MMGR_FREE (worker->server->mmgr, worker);
 }
 
@@ -2067,9 +2184,18 @@ int hcl_server_start (hcl_server_t* server, const hcl_bch_t* addrs)
 				HCL_LOG1 (server->dummy_hcl, SERVER_LOGMASK_INFO, "Accepted worker - socket %d\n", cli_fd);
 
 				worker = alloc_worker(server, cli_fd);
-				if (pthread_create(&thr, &thr_attr, worker_main, worker) != 0)
+				if (!worker)
 				{
-					free_worker (worker);
+					HCL_LOG1 (server->dummy_hcl, SERVER_LOGMASK_ERROR, "Unable to accomodate accepted worker - socket %d\n", cli_fd);
+					close (cli_fd);
+				}
+				else
+				{
+					HCL_LOG2 (server->dummy_hcl, SERVER_LOGMASK_INFO, "Assigned WID(%zd) to the accepted server socket %d\n", worker->wid, cli_fd);
+					if (pthread_create(&thr, &thr_attr, worker_main, worker) != 0)
+					{
+						free_worker (worker);
+					}
 				}
 			}
 		}
diff --git a/lib/hcl-s.h b/lib/hcl-s.h
index 9eb98bc..7ed0844 100644
--- a/lib/hcl-s.h
+++ b/lib/hcl-s.h
@@ -56,10 +56,12 @@ enum hcl_server_trait_t
 };
 typedef enum hcl_server_trait_t hcl_server_trait_t;
 
+#define HCL_SERVER_WID_INVALID ((hcl_oow_t)-1)
+#define HCL_SERVER_WID_MAX (HCL_SERVER_WID_INVALID - 1)
 
 typedef void (*hcl_server_log_write_t) (
 	hcl_server_t*     server,
-	int               wid,
+	hcl_oow_t         wid,
 	unsigned int      mask,
 	const hcl_ooch_t* msg,
 	hcl_oow_t         len
diff --git a/lib/main2.c b/lib/main2.c
index c30aade..1ac785f 100644
--- a/lib/main2.c
+++ b/lib/main2.c
@@ -117,7 +117,7 @@ static int write_all (int fd, const char* ptr, hcl_oow_t len)
 	return 0;
 }
 
-static void log_write (hcl_server_t* server, int wid, unsigned int mask, const hcl_ooch_t* msg, hcl_oow_t len)
+static void log_write (hcl_server_t* server, hcl_oow_t wid, unsigned int mask, const hcl_ooch_t* msg, hcl_oow_t len)
 {
 	hcl_bch_t buf[256];
 	hcl_oow_t ucslen, bcslen;
@@ -172,9 +172,10 @@ static void log_write (hcl_server_t* server, int wid, unsigned int mask, const h
 /* TODO: less write system calls by having a buffer */
 		write_all (logfd, ts, tslen);
 
-		if (wid >= 0)
+		if (wid != HCL_SERVER_WID_INVALID)
 		{
-			tslen = snprintf (ts, sizeof(ts), "[%x] ", wid);
+			/* TODO: check if the underlying snprintf support %zd */
+			tslen = snprintf (ts, sizeof(ts), "[%zu] ", wid);
 			write_all (logfd, ts, tslen);
 		}
 	}
diff --git a/mod/Makefile.in b/mod/Makefile.in
index 1970289..40b1ca0 100644
--- a/mod/Makefile.in
+++ b/mod/Makefile.in
@@ -376,6 +376,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@