Xerox Star GUI -- 1981After building and designing personal computers throughout the '70s, Xerox had a breakthrough in 1981 when it unveiled Star, the first system that integrated desktop computing with various technologies that are now commonplace: a bitmapped display, a GUI (graphical user interface), icons, folders, a mouse, Ethernet networking, file servers, print servers and e-mail.\nStar was ahead of its time and not commercially successful, but it was incredibly influential, setting the standard for GUIs to come from Microsoft, Apple and Sun, among others.Macintosh Desktop -- 1984The Macintosh, released in 1984 with the legendary "Big Brother" TV commercial, was the first commercially successful product to use a mouse \n\nand a GUI. It built on the Xerox Star GUI by making windows and icons easier to use with a mouse. For the first time, files and folders could be \n\ncopied by dragging and dropping them into the desired location.Mac OS 1.0 may not be remembered as a great system \u2014 the Macintosh was underpowered (it ran on 128K of RAM), expensive and not \n\nvery user-friendly \u2014 but it did bring the GUI to the masses.Amiga Workbench 1.0 -- 1985Commodore's AmigaOS computers and their accompanying Workbench desktop environment were ahead of their time. The GUI included features \n\nsuch as color graphics in black, white, blue and orange as well as preemptive multitasking, stereo sound and multi-state icons. It takes the \n\nworkbench name to heart, with directories depicted as drawers and files as tools, etc. One cool feature (at least for 1985) is that the pointer \n\nchanged into a red circle when dragging objects. But the Amiga Workbench system is best known as an early Macintosh competitor and the first GUI \n\nto use a range of colors.Windows 1.0 -- 1985Microsoft got in the GUI game with Windows 1.0, which included a GUI for the MS-DOS operating system. Windows 1 featured a multi-tasking GUI \n\nand 32-pixel icons and color graphics. At the time the Mac was strictly black and white.Nevertheless, Windows 1.0 was not a hit. It was viewed as slow and buggy (It was improved on in Windows 2.0). Also, because Windows 1 had \n\nsimilar mouse support and drop-down menus to the Macintosh, Apple threatened to sue Microsoft, but settled on a formal agreement where \n\nMicrosoft could license certain Mac OS features. However, the war had begun.RISC OS -- 1987Early versions of the RISC OS, known as Arthur, were released in 1987 by Acorn Computers for their desktop computers that used the ARM \n\nchipset (Acorn was later spun off into ARM Holdings). RISC OS was a color GUI operating system which used three-button mice and a file navigator \n\nsimilar to that of Mac OS. The RISC OS is best known for the introduction of the icon bar running apps and system utilities, which Apple later remodeled as the Mac OS X \n\ndock and Microsoft used as an influence for the Windows taskbar.OS\/2 -- 1988The OS\/2 operating system was a collaboration between Microsoft and IBM to replace DOS. Version 1.1, released in 1988, used a GUI with \n\nfeatures such as swapping and multitasking that were used in Windows 3.0 in 1990. Version 2.0 of OS\/2 featured a new, object-oriented GUI, called \n\nthe Workplace Shell (WPS), with a desktop that Microsoft would later imitate in Windows 95.Microsoft and IBM parted ways on OS\/2 in 1991 after the popularity of Windows 3.0 prompted Microsoft to shift its focus from cooperating with \n\nIBM to building its own franchise based on Windows.NeXTSTEP -- 1989After Steve Jobs was shown the door at Apple in 1985, he started the company NeXT with the goal of revolutionizing the operating system and \n\nGUI. The NeXTSTEP OS indeed broke the mold with its bigger, more colorful icons and its dock for storing and organizing applications. NeXTSTEP \n\nnever sold well (again, an interface ahead of its time), but Apple acquired NeXT in 1996, bringing Steve Jobs back into the fold and incorporating \n\nNeXTSTEP's design and UI features into the mega-successful Mac OS X.Windows 3.0 -- 1990Released in 1990, Windows 3.0 was the first version to connect with a large audience. Windows 3.0 was simply more compatible with everything \n\n-- including Intel processors --and took advantage of improved graphics on PCs due to VGA video cards. Windows 3.0 apps could also use more \n\nmemory because the OS could run in real, standard, protected and 386 enhanced modes. Visually, Windows 3.0 icons were more colorful and the \n\nGUI had a unified style. Windows 3.0 sold 10 million copies in two years, making Windows a major source of Microsoft revenue for the first time.Mac OS 7 -- 1991Mac OS 7 (also called System 7) was the most significant pre-Mac OS X upgrade. It replaced System 6 in 1991 and was the first Mac OS GUI to \n\nsupport all colors. It introduced desktop aliases and the ability to drag and drop icons that open the target they are dropped into. Other standout UI \n\nfeatures in Mac OS 7 were the Applications menu, which became a separate menu and moved to the right of the screen and the Hide\/Show \n\nfunctionality that allows users to hide apps while keeping them running. Mac OS 7 had a six-year run.Windows 95 -- 1995Within two years after its big-splash release in August 1995, Windows 95 became the most successful operating system ever built, and its GUI \n\nhad a lot to do with it. The OS introduced the Windows interface we all know: The Start Menu, the Taskbar to manage applications, the Windows \n\nExplorer File Manager, and more. It was also the first version of Windows to ship with Internet Explorer. Windows 95 was extremely popular with \n\nconsumers, putting competitors like OS\/2 out of business and keeping the struggling Mac OS in the dark.KDE -- 1998KDE was one of the leading Linux desktops of late '90s. It was designed as an easy-to-use desktop environment for Unix workstations. \n\nAlthough it has similar GUI features to Mac OS and Windows 95, it was one of the first and most notable open desktop platforms that allowed its \n\nsource code to be modified by anyone free of charge.GNOME -- 1999Similar to KDE in look and feel, GNOME offered another free desktop GUI for Linux and open-source enthusiasts who were popping up in the late \n\n'90s. GNOME desktop was mainly developed for Red Hat Linux, but it was later developed for other Linux distributors. Like KDE, the GNOME desktop \n\ncreates a GUI environment on par with Windows and Mac OS. As the two open-source GUIs evolved, a serious rivalry between KDE and GNOME users \n\nignited in the Linux world, and remains to this day.Windows XP -- 2001Microsoft reached a peak with Windows 95, and would reach another peak in 2001 with Windows XP, the most successful version of the OS. It \n\nwas designed to replace both the lukewarm Windows 2000 and miserable Windows ME. XP got Microsoft back on track with new interface features \n\nsuch as the "Luna" visual theme, a redesigned Start Menu, Cleartype fonts and task grouping in the Taskbar. XP updates added improved Wi-Fi \n\nsupport and the Windows Security Center. XP flourished for over five years until Vista released in January 2007, the longest time between Windows \n\nreleases.Mac OS X -- 2001Mac OS X marked the beginning of a new wildly successful era for Apple, and for GUIs in general. The OS was a massive revision and Apple has \n\nupdated it about every two years with names from the feline family (Cheetah, Tiger, Leopard, etc). Mac OS X was made up of Unix-based \n\ntechnologies developed by NeXT, the company Steve Jobs founded during his exile from Apple. The GUI is best known for its "Aqua" interface, its \n\nDock, much bigger icons with soft edges and translucent colors, and the ability to run multiple apps simultaneously without them interrupting each \n\nother. Windows Vista -- 2007Microsoft released Windows Vista later than promised in January of 2007. And the late release in the dead of winter was a harbinger of bad \n\nthings to come, as Vista became a black mark on Windows history. What started out as the "Wow" product became the butt of jokes and source of \n\nfrustration due to the expensive price, high system requirements, sluggishness, and annoying UAC prompts. Nevertheless, Vista did have innovative \n\nGUI features, including: the Aero visual interface, thumbnail previews from the taskbar, Windows Instant Search, Windows Flip 3D and a redesigned \n\nStart Menu.Mac OS X Leopard -- 2007Mac OS X Leopard, released in 2007, stands out among other OS X updates because it included the most changes. According to Apple, Leopard \n\ncontained over 300 enhancements over its predecessor, Mac OS X Tiger, including applications, developer tools and a revised desktop. GUI changes \n\nin Leopard included: a redesigned 3D Dock and a more 3D look overall, a semitransparent menu bar, and an updated Finder that incorporates the \n\nCover Flow visual navigation interface first seen in iTunes. Other notable features include support for writing 64-bit GUI applications, and an \n\nautomated backup utility called Time Machine.Windows 7 -- 2009Windows 7 redeemed the problems of Vista, winning over consumers and businesses because of its speed and flexibility, but also because of its \n\nnew GUI features, including a revamped taskbar that includes pinned icons and jump lists. It also built on the Aero visual style from Vista with \n\nfeatures like Aero Snap, which allows you to place two windows side by side and Aero Shake, which lets you minimize all other windows by shaking \n\nthe current window. It also gave users more control over UAC settings, a welcome fix of a Vista shortcoming.Mac OS X Lion -- 2011Mac OS X Lion is the first client OS to incorporate touch-screen UI features, a move to capitalize on the soaring popularity of iOS. Some GUI \n\nfeatures in Lion that are clearly designed to merge the Mac and the iPad are: scroll bars that disappear when not being used; Touchpad gestures to \n\nflick, swipe, and pinch-to-zoom; a home screen (called Launchpad in Lion) that displays your apps in rows; and apps that occupy the entire screen \n\nwhen opened.Reaction to Lion has been mixed, as multi-touch features take some getting used to on a computer.Windows 8 -- 2012Windows 8 will not be generally available until 2012, but we know it will have a completely new GUI based on the Metro design of Windows \n\nPhone 7. Yes, Windows 8 is following the same path as Mac OS X Lion by blending tablet-like touch-screen capabilities with traditional client OS \n\nfeatures. The Windows 8 start screen is a colorful grid of touch-based tiles that represent each of your apps. They can be swiped, pinched, and \n\ntapped with your finger. Tiles will also be accessed via a mouse and keyboard, so purists need not worry.