diff --git a/agent.py b/agent.py
index eb09cae..1b623ec 100644
--- a/agent.py
+++ b/agent.py
@@ -96,12 +96,12 @@ class ServerData:
         with open('/proc/meminfo', 'r') as f:
             meminfo = f.read()
         ram = int([x for x in meminfo.split('\n') if 'MemTotal' in x][0].split()[1]) // 1024
-
-        # Disk space information
+       # Disk space information
         disk = 0
         for device in os.listdir('/sys/block'):
-            size_path = f'/sys/block/{device}/size'
-            if os.path.exists(size_path) and os.access(size_path, os.R_OK):
+            device_path = '/sys/block/{}/device'.format(device)
+            size_path = '/sys/block/{}/size'.format(device)
+            if os.path.islink(device_path):
                 try:
                     with open(size_path, 'r') as f:
                         size = int(f.read().strip())
@@ -110,7 +110,7 @@ class ServerData:
                     pass  # Skip the device if any exception occurs
 
         disk = disk * 512 // (1024**3)  # convert to GB
-        logging.info(f"RAM: {ram}MB, Disk: {disk}GB")
+        logging.info("RAM: {}MB, Disk: {}GB".format(ram, disk))
         return ram, disk
 
     def get_cpu_count(self):
@@ -124,12 +124,12 @@ class ServerData:
             with open('/proc/cpuinfo', 'r') as f:
                 cpuinfo = f.read()
             cpu_count = cpuinfo.count('processor')
-        logging.info(f"CPU Count: {cpu_count}")
+        logging.info("CPU Count: {}".format(cpu_count))
         return cpu_count
 
     def get_bandwidth(self):
         bandwidth = 2000
-        logging.info(f"Bandwidth: {bandwidth}")
+        logging.info("Bandwidth: {}".format(bandwidth))
         return bandwidth
 
     def get_public_ip(self):
@@ -137,12 +137,12 @@ class ServerData:
             response = urllib.request.urlopen('https://api.ipify.org')
             return response.read().decode()
         except Exception as e:
-            logging.error(f"Failed to get public IP: {e}")
+            logging.error("Failed to get public IP: {}".format(e))
             return '127.0.0.1'
 
     def get_os(self):
         os_id = 27
-        logging.info(f"OS ID: {os_id}")
+        logging.info("OS ID: {}".format(os_id))
         return os_id
 
     def create_post_data(self):
@@ -235,7 +235,7 @@ class ServerManager:
                 else:
                     return response.read().decode()
         except urllib.error.HTTPError as e:
-            logging.error(f"Request failed with {e}")
+            logging.error("Request failed with {}".format(e))
             raise
 
     def get_existing_servers(self):
@@ -249,7 +249,7 @@ class ServerManager:
         return self.send_request('POST', '/api/notes', post_data)
 
     def update_note(self, post_data, service_id):
-        logging.info(f"Updating note with id {service_id}...")
+        logging.info("Updating note with id {}...".format(service_id))
         return self.send_request('PUT', '/api/notes/' + str(service_id), post_data)
 
     def create_server(self, post_data):
@@ -260,7 +260,7 @@ class ServerManager:
         # remove following keys from post_data
         for key in NON_UPDATABLE_KEYS:
             post_data.pop(key, None)
-        logging.info(f"Updating server with id {server_id}...")
+        logging.info("Updating server with id {}...".format(server_id))
         return self.send_request('PUT', '/api/servers/' + str(server_id), post_data)
 
     def existing_server_id(self, post_data):