Criticism of Windows Vista including Photoshop and WinRAR, also performed worse under Vista. Many low-to-mid-end machines that come with Windows Vista pre-installed suffer from exceptionally slow performance with the default Vista settings that come pre-loaded, and laptop manufacturers have offered to "downgrade" laptops to Windows XP—for a price. However, this "price" is unnecessary, as Microsoft allows users of Windows Vista and Windows 7 to freely "downgrade" their software by installing XP and then phoning a Microsoft representative for a new product key. When first released in November 2006, Vista performed file operations such as copying and deletion more slowly than other operating systems. Large
Operating system systems that have fixed deadlines use a real-time operating system such as VxWorks, PikeOS, eCos, QNX, MontaVista Linux and RTLinux. Windows CE is a real-time operating system that shares similar APIs to desktop Windows but shares none of desktop Windows' codebase. Symbian OS also has an RTOS kernel (EKA2) starting with version 8.0b. Some embedded systems use operating systems such as Palm OS, BSD, and Linux, although such operating systems do not support real-time computing. Operating system development is one of the most complicated activities in which a computing hobbyist may engage. A hobby operating system may be classified as