if(getFileSystem().isReadOnly()) { throw new ReadOnlyFileSystemException("addFile in readonly filesystem"); }
	protected synchronized FatDirEntry addFatFile(String nameExt) throws IOException {		if (getFatEntry(nameExt) != null) {			throw new IOException("File already exists" + nameExt);		}		final FatDirEntry newEntry = new FatDirEntry(this, splitName(nameExt), splitExt(nameExt));		int size = entries.size();		for (int i = 0; i < size; i++) {			FatBasicDirEntry e = (FatBasicDirEntry)entries.get(i);			if (e == null) {				entries.set(i, newEntry);				setDirty();				flush();				return newEntry;			}		}		int newSize = size + 512 / 32;		if (canChangeSize(newSize)) {			entries.ensureCapacity(newSize);			setDirty();			flush();			return newEntry;		}		throw new IOException("Directory is full");	}