In answer to the release of Apple’s Mac OS and other graphical user interfaces (GUIs) available for the PC, Microsoft released the first version of Windows in 1985 which used MS-DOS as the underlying operating system. Since then Windows has undergone many changes, with Windows 10 the latest version released in 2015 aimed at three sectors of the market, embedded devices, mobiles phones and computer systems, each featuring a sub-family aimed at different user requirements.
Despite Mac OS based systems being released a year earlier, Windows based systems have gone on to dominate the desktop PC market as the most commonly used operating system. With such a dominant position in the market and a long history, we have therefore seen a huge number of hard disk drives arrive for data recovery using each supported file system type available to Windows systems.
MS-DOS System Core
The MS-DOS operating system formed the core of the most desktop systems, as it needed to be loaded before Windows could be started. The last version of to use this model was Windows Millennium (ME) which featured most of the same limitations inherent in all previous versions. Hard disk capacities were increasing rapidly, which required special drivers, with FAT based file systems the only option available.
Windows systems were designed to allow multiple programs to be run at the same time, but early versions used a method called cooperative multitasking, whereby programs not needing any CPU time were required to yield resources to other applications. Such a method of multitasking was prone to an issue known as deadlock, whereby the operating system would freeze, usually only resolved by rebooting, leading to regular loss of work. Cooperative multitasking was abandoned for the release of Windows 95 in favour of pre-emptive multitasking resulting in a considerably more stable system.
New Technology (NT) and Server Based Systems
As early as 1988 Microsoft recognised the need for a proper secure multi-user capable operating system when they started work on revamping the OS/2 operating system given the name New Technology (NT). Windows 3.0 proved however, to be such a success that Microsoft shelved their plans, to work on extending the 32-bit Windows API port called Win32. In 1993 Microsoft released Windows NT 3.1 for servers and workstations which introduced the NTFS file system. Two years later NT 3.51 was released with the important addition of Novell NetWare networking. Only a year later NT 4.0 was released using the same user interface as Windows 95.
Windows 2000 superseded this in 2000, largely aimed at the business sector forming the basis for its successors renamed as Windows Server (2003, 2008 and 2012) all of which are specifically optimised for file sharing, website hosting and running services such as SQL and Exchange servers.
64 Bit XP and the Future
Microsoft retired the Windows 9x series of operating systems when they unified the projects releasing consumer and server versions of Windows XP and later Vista with Home and Pro releases. Windows 7 through 8 and its sub-releases increased the range to include the Ultimate version, renamed to Enterprise with the release of Windows 10. When Windows 8 was released further unification of the platform occurred, with Windows Mobile replaced, allowing simplified development for applications developers. The introduction of the 64 bit version of XP was only available for the Pro release, although all subsequent versions of Windows are available for 32 bit and 64 bit processors.
Multiple hard disk drives and SAN server space provided via iSCSI can be configured as a software RAID using the Professional, Ultimate/Enterprise and Server versions of the Windows operating system. Microsoft announced a change in their licencing model with the release of Windows 10 in May 2015, with no charge for updating to each new version of the operating system. This model also included free upgrades to Windows 10 from Windows 7 and 8 available to the end of July 2016. Many proposals to for developing an intelligent file system capable of optimising data storage, NTFS has remained the default file system, looking set to remain so for the foreseeable future.