diff --git a/cpukit/libfs/src/dosfs/fat.c b/cpukit/libfs/src/dosfs/fat.c
index 88b4a2859b..e9de85f738 100644
--- a/cpukit/libfs/src/dosfs/fat.c
+++ b/cpukit/libfs/src/dosfs/fat.c
@@ -364,7 +364,7 @@ fat_cluster_set(
         ofs_blk,
         c,
         pattern);
-    if (c != ret)
+    if ((ssize_t)c != ret)
       rc = -1;
     else
     {
@@ -444,7 +444,7 @@ fat_cluster_write(
           ofs_blk,
           c,
           &buffer[bytes_written]);
-      if (c != ret)
+      if ((ssize_t)c != ret)
         rc = -1;
       else
       {
@@ -921,7 +921,7 @@ fat_init_clusters_chain(
     while ((cur_cln & fs_info->vol.mask) < fs_info->vol.eoc_val)
     {
         ret = fat_cluster_set(fs_info, cur_cln, 0, fs_info->vol.bpc, 0);
-        if ( ret != fs_info->vol.bpc )
+        if ( ret != (ssize_t)fs_info->vol.bpc )
         {
             return -1;
         }
diff --git a/cpukit/libfs/src/dosfs/fat_file.c b/cpukit/libfs/src/dosfs/fat_file.c
index 161af94ae3..ea05b2bcf3 100644
--- a/cpukit/libfs/src/dosfs/fat_file.c
+++ b/cpukit/libfs/src/dosfs/fat_file.c
@@ -713,7 +713,7 @@ fat_file_extend(
             return rc;
 
         bytes_written = fat_cluster_set (fs_info, cur_cln, ofs, bytes_remain, 0);
-        if (bytes_remain != bytes_written)
+        if ((ssize_t)bytes_remain != bytes_written)
             return -1;
     }
 
diff --git a/cpukit/libfs/src/dosfs/msdos_conv.c b/cpukit/libfs/src/dosfs/msdos_conv.c
index ba28a07512..01e657d2be 100644
--- a/cpukit/libfs/src/dosfs/msdos_conv.c
+++ b/cpukit/libfs/src/dosfs/msdos_conv.c
@@ -414,7 +414,7 @@ msdos_filename_utf8_to_long_name_for_save (
     uint16_t                        *long_name,
     const size_t                     long_name_size)
 {
-    ssize_t      returned_size = 0;
+    size_t       returned_size = 0;
     int          eno           = 0;
     size_t       name_size;
     size_t       name_size_tmp;
diff --git a/cpukit/libfs/src/dosfs/msdos_format.c b/cpukit/libfs/src/dosfs/msdos_format.c
index 910aa0aedf..7686ba1a26 100644
--- a/cpukit/libfs/src/dosfs/msdos_format.c
+++ b/cpukit/libfs/src/dosfs/msdos_format.c
@@ -783,7 +783,7 @@ static int msdos_format_determine_fmt_params
   if (ret_val == 0) {
       const char *from;
       char        *to = fmt_params->OEMName;
-      int          cnt;
+      size_t       cnt;
       from = "RTEMS"; /* default: make "from" point to OS Name */
     if ((rqdata != NULL) && (rqdata->OEMName != NULL)) {
       from = rqdata->OEMName;
@@ -810,7 +810,7 @@ static int msdos_format_determine_fmt_params
   if (ret_val == 0) {
       const char *from;
       char        *to = fmt_params->VolLabel;
-      int          cnt;
+      size_t       cnt;
       from = ""; /* default: make "from" point to empty string */
     if ((rqdata != NULL) &&
         (rqdata->VolLabel != NULL)) {
diff --git a/cpukit/libfs/src/dosfs/msdos_misc.c b/cpukit/libfs/src/dosfs/msdos_misc.c
index 072169ba9e..ed423231a2 100644
--- a/cpukit/libfs/src/dosfs/msdos_misc.c
+++ b/cpukit/libfs/src/dosfs/msdos_misc.c
@@ -1264,7 +1264,7 @@ msdos_compare_entry_against_filename (
                  entry,
                  filename );
 #endif
-        if (bytes_in_entry_normalized <= size_remaining) {
+        if (bytes_in_entry_normalized <= (size_t) size_remaining) {
             size_remaining = size_remaining - bytes_in_entry_normalized;
             if (0 == memcmp ( &entry_normalized[0],
                               &filename[size_remaining],
@@ -1356,7 +1356,7 @@ msdos_find_file_in_directory (
         if (bytes_read < MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE)
             rtems_set_errno_and_return_minus_one(EIO);
 
-        assert(bytes_read == bts2rd);
+        assert(bytes_read == (ssize_t)bts2rd);
 
         /* have to look at the DIR_NAME as "raw" 8-bit data */
         for (dir_entry = 0;
@@ -1691,7 +1691,7 @@ msdos_add_file (
     int              ret;
     ssize_t          bytes_written;
     uint8_t          lfn_checksum;
-    int              lfn_entry;
+    unsigned int     lfn_entry;
     uint8_t         *entry;
     uint32_t         short_file_offset;
     uint32_t         length;
@@ -2033,7 +2033,7 @@ int msdos_find_node_by_cluster_num_in_fat_file(
         if ( ret < MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE )
             rtems_set_errno_and_return_minus_one( EIO );
 
-        assert(ret == bts2rd);
+        assert(ret == (ssize_t)bts2rd);
 
         for (i = 0; i < bts2rd; i += MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE)
         {