diff --git a/src/Kernel/BlkDev/DiskClus.ZC b/src/Kernel/BlkDev/DiskClus.ZC
index 87dbe401..d24b9c9f 100755
--- a/src/Kernel/BlkDev/DiskClus.ZC
+++ b/src/Kernel/BlkDev/DiskClus.ZC
@@ -141,6 +141,10 @@ I64 ClusBlkWrite(CDrive *drive, U8 *buf, I64 c, I64 blks)
 				}
 				break;
 
+			case FSt_ISO9660:
+				PrintErr("File System Not Writable\n");
+				throw('Drive');
+
 			default:
 				throw('Drive');
 		}
@@ -178,6 +182,11 @@ I64 ClusAlloc(CDrive *drive, I64 c=0, I64 count=1, Bool contiguous=FALSE)
 			else
 				return FAT32AllocClus(drive, c, count);
 
+
+		case FSt_ISO9660:
+			PrintErr("File System Not Writable\n");
+			throw('Drive');
+
 		default:
 			throw('Drive');
 	}
diff --git a/src/Kernel/BlkDev/DiskCopy.ZC b/src/Kernel/BlkDev/DiskCopy.ZC
index 52aa6b7a..87ce38f6 100755
--- a/src/Kernel/BlkDev/DiskCopy.ZC
+++ b/src/Kernel/BlkDev/DiskCopy.ZC
@@ -113,6 +113,10 @@ I64 Del(U8 *files_find_mask, Bool make_mask=FALSE, Bool del_dir=FALSE, Bool prin
 				res = FAT32FilesDel(dirc->drive, Fs->cur_dir, dirc->mask, 0, del_dir, print_message);
 				break;
 
+			case FSt_ISO9660:
+				PrintErr("File System Not Writable\n");
+				break;
+
 			default:
 				PrintErr("File System Not Supported\n");
 		}
diff --git a/src/Kernel/BlkDev/DiskDirA.ZC b/src/Kernel/BlkDev/DiskDirA.ZC
index 133750dd..cfaa5ba4 100755
--- a/src/Kernel/BlkDev/DiskDirA.ZC
+++ b/src/Kernel/BlkDev/DiskDirA.ZC
@@ -8,6 +8,10 @@ Bool DirNew(CDrive *drive, U8 *cur_dir, CDirEntry *tmpde, Bool free_old_chain=TR
 		case FSt_FAT32:
 			return FAT32DirNew(drive, cur_dir, tmpde, free_old_chain);
 
+		case FSt_ISO9660:
+			PrintErr("File System Not Writable\n");
+			return FALSE;
+
 		default:
 			PrintErr("File System Not Supported\n");
 			return FALSE;
diff --git a/src/Kernel/BlkDev/DiskDirB.ZC b/src/Kernel/BlkDev/DiskDirB.ZC
index e8f2a3fd..96f06abe 100755
--- a/src/Kernel/BlkDev/DiskDirB.ZC
+++ b/src/Kernel/BlkDev/DiskDirB.ZC
@@ -69,7 +69,7 @@ Bool Cd(U8 *dirname=NULL, Bool make_dirs=FALSE)
 					res = RedSeaCd(buf, cur_dir_clus);
 					break;
 				case FSt_ISO9660:
-					res = ISOCd(buf,cur_dir_clus);
+					res = ISOCd(buf, cur_dir_clus);
 					break;
 				case FSt_FAT32:
 					res = FAT32Cd(buf, cur_dir_clus);
@@ -153,7 +153,7 @@ I64 Dir(U8 *files_find_mask, Bool full)
 
 			"$$MA,T=\"Directory\",LM=\"PopUpCd;Dir;\n\"$$ of %s\n", st;
 			if (full)
-				"__DATE__ __TIME__ %*ts %*ts\n", csize, "SIZE", c, "BLK";
+				"__DATE__ __TIME__ %*ts %*ts\n", csize, "SIZE", c, "CLUS";
 			else
 				"DATE_ TIME_ %*ts\n", csize, "SIZE";
 			while (tmpde1)
@@ -212,6 +212,10 @@ Bool DirMake(U8 *filename, I64 entry_count=0)
 						res = FAT32MkDir(dirc->drive, Fs->cur_dir, name, entry_count);
 						break;
 
+					case FSt_ISO9660:
+						PrintErr("File System Not Writable\n");
+						break;
+
 					default:
 						PrintErr("File System Not Supported\n");
 				}
diff --git a/src/Kernel/BlkDev/DiskFile.ZC b/src/Kernel/BlkDev/DiskFile.ZC
index b7a81a43..107bf131 100755
--- a/src/Kernel/BlkDev/DiskFile.ZC
+++ b/src/Kernel/BlkDev/DiskFile.ZC
@@ -103,6 +103,10 @@ I64 FileWrite(U8 *filename, U8 *fbuf, I64 size, CDate cdt=0, I64 attr=0)
 				c = FAT32FileWrite(dirc->drive, Fs->cur_dir, dirc->mask, fbuf, size, cdt, attr);
 				break;
 
+			case FSt_ISO9660:
+				PrintErr("File System Not Writable\n");
+				break;
+
 			default:
 				PrintErr("File System Not Supported\n");
 		}
diff --git a/src/Kernel/BlkDev/DiskFormat.ZC b/src/Kernel/BlkDev/DiskFormat.ZC
index 0e1b696b..a66a8614 100755
--- a/src/Kernel/BlkDev/DiskFormat.ZC
+++ b/src/Kernel/BlkDev/DiskFormat.ZC
@@ -37,6 +37,10 @@ Bool DriveTypeSet(U8 drv_let, I64 type=FSt_REDSEA)
 										mbr.p[i].type = MBR_PT_FAT32a;
 										break;
 
+									case FSt_ISO9660:
+										PrintErr("File System Not Writable\n");
+										throw('Drive');
+
 									default:
 										throw('Drive');
 								}