def ReadDiskBytes(volume_letter: str, start_byte: int, length: int) -> bytes:
    """
    从指定磁盘的指定起始位置读取指定长度的字节。

    :param volume_letter: 盘符（如 "Y"）
    :param start_byte: 起始字节位置（整数）
    :param length: 要读取的字节数（整数）
    :return: 读取到的原始字节数据（bytes）
    """
    if not isinstance(volume_letter, str) or len(volume_letter.strip()) != 1:
        raise ValueError("drive_letter 必须是单个字母，如 'Y'")

    # 构建 Windows 设备路径格式：\\.\Y:
    disk_path = f"\\\\.\\{volume_letter.strip().upper()}:"

    try:
        with open(disk_path, "rb") as disk:
            disk.seek(start_byte)
            data = disk.read(length)
            return data
    except PermissionError:
        raise PermissionError("权限不足，请以管理员身份运行程序")
    except Exception as e:
        raise RuntimeError(f"读取磁盘失败：{e}")


if __name__ == "__main__":
    drive = "Y"
    start = 687685632
    size = 7163904

    try:
        content = ReadDiskBytes(drive, start, size)
        print(f"成功读取 {len(content)} 字节内容。前100字节为：")
        print(content[:100])
    except Exception as e:
        print("错误：", e)