diff --git a/biostools/__main__.py b/biostools/__main__.py
index eecd7d8..37da4e0 100644
--- a/biostools/__main__.py
+++ b/biostools/__main__.py
@@ -26,11 +26,11 @@ DEFAULT_REMOTE_PORT = 8620
 
 # Extraction module.
 
-def extract_dir(file_extractors, dir_number_path, next_dir_number_path, scan_dir_path, scan_file_names):
+def extract_dir(file_extractors, subdir_trim_index, path_trim_index, next_dir_number_path, scan_dir_path, scan_file_names):
 	"""Process a given directory for extraction."""
 
 	# Determine the destination subdirectory.
-	dest_subdir = scan_dir_path[len(dir_number_path):]
+	dest_subdir = scan_dir_path[subdir_trim_index:]
 	while dest_subdir[:len(os.sep)] == os.sep:
 		dest_subdir = dest_subdir[len(os.sep):]
 
@@ -79,7 +79,7 @@ def extract_dir(file_extractors, dir_number_path, next_dir_number_path, scan_dir
 				# Handle the line break ourselves, since Python prints the main
 				# body and line break separately, causing issues when multiple
 				# threads/processes are printing simultaneously.
-				print('{0} => {1}{2}\n'.format(file_path, extractor.__class__.__name__, (extractor_result == True) and ' (skipped)' or ''), end='')
+				print('{0} => {1}{2}\n'.format(file_path[path_trim_index:], extractor.__class__.__name__, (extractor_result == True) and ' (skipped)' or ''), end='')
 				break
 
 		# Remove destination directories if they were created but are empty.
@@ -124,12 +124,17 @@ def extract_process(queue, dir_number_path, next_dir_number_path, debug):
 		for extractor in file_extractors:
 			extractor.debug_print = dummy_func
 
+	# Cache trim index values for determining a file's relative paths.
+	dir_number_path = dir_number_path.rstrip(os.sep)
+	subdir_trim_index = len(dir_number_path)
+	path_trim_index = len(os.path.dirname(dir_number_path)) + len(os.sep)
+
 	# Receive work from the queue.
 	while True:
 		item = queue.get()
 		if item == None: # special item to stop the loop
 			break
-		extract_dir(file_extractors, dir_number_path, next_dir_number_path, *item)
+		extract_dir(file_extractors, subdir_trim_index, path_trim_index, next_dir_number_path, *item)
 
 def extract(dir_path, _, options):
 	"""Main function for extraction."""
@@ -168,7 +173,7 @@ def extract(dir_path, _, options):
 		# Start multiprocessing pool.
 		print('Starting extraction on directory {0}'.format(dir_number), end='', flush=True)
 		queue_size = options['threads'] + len(options['remote_servers'])
-		queue = multiprocessing.Queue(maxsize=queue_size)
+		queue = multiprocessing.Queue(maxsize=queue_size * 4)
 		initargs = (queue, dir_number_path, next_dir_number_path, options['debug'])
 		mp_pool = multiprocessing.Pool(options['threads'], initializer=extract_process, initargs=initargs)
 		print(flush=True)
@@ -214,9 +219,7 @@ def extract(dir_path, _, options):
 		mp_pool.close()
 		mp_pool.join()
 
-		# Stop remote clients and wait for them to finish.
-		for client in remote_clients:
-			client.close()
+		# Wait for remote clients to finish.
 		for client in remote_clients:
 			client.join()
 
@@ -395,16 +398,16 @@ def analyze_dir(formatter, scan_base, file_analyzers, scan_dir_path, scan_file_n
 		found_flag_file = True
 		while found_flag_file:
 			# Find archive indicator.
-			archive_idx = scan_file_path_full.rfind(':' + os.sep)
-			if archive_idx == -1:
+			archive_index = scan_file_path_full.rfind(':' + os.sep)
+			if archive_index == -1:
 				break
 
 			# Check if a combined or header flag file exists.
 			found_flag_file = False
 			for flag_file in (':combined:', ':header:'):
-				if os.path.exists(os.path.join(scan_file_path_full[:archive_idx] + ':', flag_file)):
+				if os.path.exists(os.path.join(scan_file_path_full[:archive_index] + ':', flag_file)):
 					# Trim the directory off.
-					scan_file_path_full = scan_file_path_full[:archive_idx]
+					scan_file_path_full = scan_file_path_full[:archive_index]
 					found_flag_file = True
 					break
 
@@ -583,7 +586,7 @@ def analyze(dir_path, formatter_args, options):
 		dir_path = dir_path[:-1]
 
 	# Start multiprocessing pool.
-	queue = multiprocessing.Queue(maxsize=options['threads'])
+	queue = multiprocessing.Queue(maxsize=options['threads'] * 4)
 	mp_pool = multiprocessing.Pool(options['threads'], initializer=analyze_process, initargs=(queue, formatter, dir_path, options['debug']))
 
 	if os.path.isdir(dir_path):
@@ -763,7 +766,7 @@ class RemoteServerClient:
 			if line[0:1] in b'xa':
 				# Start multiprocessing pool.
 				print(self.addr, 'Starting pool for', (line[0] == b'x') and 'extraction' or 'analysis')
-				self.queue = multiprocessing.Queue(maxsize=self.options['threads'])
+				self.queue = multiprocessing.Queue(maxsize=self.options['threads'] * 4)
 				if line[0:1] == b'x':
 					func = extract_process
 				else:
diff --git a/biostools/extractors.py b/biostools/extractors.py
index 98b30e1..19440ab 100644
--- a/biostools/extractors.py
+++ b/biostools/extractors.py
@@ -2438,9 +2438,9 @@ class VMExtractor(ArchiveExtractor):
 				fn = in_f.read(12) # filename
 				if fn == None:
 					break
-				idx = fn.find(b'\x00')
-				if idx > -1:
-					fn = fn[:idx]
+				nul_index = fn.find(b'\x00')
+				if nul_index > -1:
+					fn = fn[:nul_index]
 				if len(fn) == 0:
 					break
 				fn = fn.decode('cp437', 'ignore')