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A Brief History of Modern Operating Systems

If there is one thing that defines modern computing, it is the operating systems that we rely on to make our computers work. Over the past few decades, OS development has gone hand in hand with the rapid development of computer technology Love them or hate them, the release of a new OS is always big news.

We will take a look at operating systems of the past, across all platforms, highlighting key upgrades and discussing milestones in OS development.

Obviously this is a massive topic area to write about, and we will be focusing heavily on those systems which were of most significance to the modern home computer, and mobile device markets. By necessity much will be omitted.

This will be a whistle-stop tour through the history of operating systems, starting with mainframe computing and the early command line interface systems, through to GUI based software and mobile operating systems.

The prehistory of home computing – mainframes and firmware.

The very earliest computers didn’t have an operating system at all; they were mainframes on which programs were coded and run individually. As the speed and processing power of computers progressed, this individual approach to running programs became more and more inefficient. Additional software was needed to manage separate tasks and prioritise workloads. Because computer run time was an expensive resource, security also became a consideration. Over time these separate processes evolved into the operating system as we understand it today.

The earliest operating systems were highly specialised, and tended to be encoded into device as hard to modify “firmware”. Later operating systems would take advantage of writable media to allow a separate OS to be loaded over the framework of a more straightforward firmware. For example, your own home computer today will still have an integrated BIOS system that enables your computer’s main operating system to boot up and which will allow you a measure of control over the computer’s hardware.

Unix - the one true OS

Of course, no discussion of operating systems could possibly be complete without mentioning Unix and it’s progeny. Unix is a multi-user computer system that evolved out of work at AT&T Bells labs. Unix has provided the basis for most server software and has provided the framework for lots of later software including, eventually, OSX, and (through Linux) Android. The Unix trademark is now owned by The Open Group, a consortium that certifies software fitting with a Single Unix Specification. There is however a wide range of important software that has developed from the Unix lineage ,such as Linux, and many versions of BSD that remain uncertified and open source.

The Personal computer era, rise of the DOS

The earliest home computers tended to feature firmware with the possibility of an additional OS offered as secondary option, if at all, especially as the first removable media was highly expensive.

However, with the increasing power of home computers, there was also an increase in the number of standardised systems and components. Rather than create unique firmware for each type of machine, it made more sense to create standardised software that would still need to be configured for each system as required, but which reused “modules” of code wherever possible. Furthermore, a concurrent reduction in the cost of removable media, such as floppy disks, made it desirable for this OS software to run from, or at least be loaded from disks, allowing it to be easily updated. Thus the DOS (Disk Operating System) software was born.


The reason for Microsoft’s present day success is undoubtedly the decision in 1981 to fulfil IBM’s request for an operating system for its new IBM PC computers. Microsoft did not write the software itself, but instead acquired the existing 86-DOS (otherwise known as QSDOS or the Quick and Dirty Operating system) Rechristened MSDOS, the new software quickly went from strength to strength. IBM licensed the software to use as its own IBM PC DOS, and these IBM PC’s were fantastically successful, so much so that their architecture quickly became the new standard not just for IBM but for third party computer manufacturers, leaving Microsoft well placed to dominate the computer market for years to come.

MSDOS was distinct from more modern operating systems in that it didn’t feature a GUI, or graphical user interface, instead using a command line interface, in which the user interacted with the software by typing in text directly. MSDOS would go through 8 major updates (often available to support different hardware configurations) until it was finally discontinued in 2000. Despite this, the command line interface, and much of the attendant functionality, would continue to be present in versions of Microsoft windows.

Xerox goes “guey”

While the likes of MSDOS made for extremely effective operating systems in experienced hands, more casual users found it difficult to learn to use them quickly or effectively. What was needed was a more intuitive way of operating computers, the GUI or graphical user interface. Interestingly many of the innovations that define the modern GUI were not made by Microsoft or Apple, and predate DOS, arising out of the work of Xerox in the 70’s. Xerox’s Alto as well as the much later STAR would debut a number of features familiar to today’s users, including the concept of a “desktop” containing file icons.

Despite its many advances, the Star was not a huge commercial success. The workstation was sold as part of an expensive integrated system, it could be slow and unreliable, and Xerox itself probably failed to realise the potential of its work.

However, if Xerox itself had failed to make the most of the GUI, others would not make the same mistake, especially as an earlier FTC ruling against Xerox had left it badly placed to adequately protect many features of its software.

Apple enters the scene

Enter the newly formed Apple with its first two offerings, the Lisa and the Macintosh. The Lisa, which was released first, stalling as a result of its high price, but the likewise pricey Macintosh would go on to see more success, partly as a result of the combination of Apple’s affordable LaserWriter printer and Adobe’s PageMaker software jumpstarting the home publishing revolution. Apple’s GUI would “borrow” a number of features from Xerox’s (which Jobs had previewed) but also introduced a number of new innovations including drag and drop, and pop-up menus.

Apple enters the wilderness?

Unfortunately Apple’s new CEO chose to celebrate the company’s success by ousting the man the many would later come to see as their Golden Goose, Steve Jobs, entering the period of time that many would later term the company’s wilderness years, an arguably unfair description. Apple would still see a measure of success during much of this period, most notably with the launch of the first PowerBooks. However Apple’s OS upgrades during this period were more incremental than revolutionary and given its high price, the company would ultimately struggle to compete with MSDOS based systems and the next new OS on the scene.

Apple enters the wilderness?

Unfortunately Apple’s new CEO chose to celebrate the company’s success by ousting the man the many would later come to see as their Golden Goose, Steve Jobs, entering the period of time that many would later term the company’s wilderness years, an arguably unfair description. Apple would still see a measure of success during much of this period, most notably with the launch of the first PowerBooks. However Apple’s OS upgrades during this period were more incremental than revolutionary and given its high price, the company would ultimately struggle to compete with MSDOS based systems and the next new OS on the scene.

Microsoft Windows

Windows 1.0, released in 1985, was Microsoft’s first attempt at releasing a GUI under its own name (Microsoft had earlier worked with Apple on development of its own GUI, something that would later trigger litigation between the two companies). The early versions of windows were not an entire operating system but rather a graphical operating environment that extended the functionality of Microsoft DOS and which didn’t garner much popularity. Things picked up slightly with windows 2 which supported the new Office and Excel software, but Microsoft’s real big success story came with windows 3, with a new and drastically improved interface. Success continued with a 3.1 release that added several minor but key features, including the much maligned BSOD (or Blue Screen of Death).

OS/2 - NT

At this point, windows development diverged with the advent of the NT line of software. In the late ‘80s Microsoft had collaborated with IBM on OS/2, a successor to DOS. This was a long term project that was eventually halted by Microsoft and IBM’s worsening relationship. IBM would continue to develop its own version of OS/2 while Microsoft’s as yet unreleased OS/2 3.0 became Windows NT. NT3.1 (named to present as a continuation of windows 3.1) was released in 1993.

A purely 32 bit operating system, NT was intended for workstations, offering greater security and stability than consumer versions of the software which were still based on MSDOS, at the cost of reduced plug and play capability and the inability to use most software featuring 3D visuals, due to a lack of Direct X support.


The continuation of the DOS based, consumer focused OSs, Windows 95 nevertheless worked to divorce itself from its DOS routes, loading DOS only as part of the boot up process. Windows 95 enabled home users to take advantage of 32 bit processors and increased memory. The nest iterations of Windows, 98 offered improved driver and USB support, and a FAT32 file system that allowed for larger hard drive partitions. Then finally Windows DOS based era came to an inglorious end at the turn of the Millennium with the release of the much maligned Millennium Edition. Always intended as a stopgap, ME was primarily famous for its introduction of Microsoft’s movie maker software, its comprehensive suite of stability bugs, and a system restore function that was notorious for reincarnating malware that had previously been removed from the system.

The end of DOS, Windows 2000 and XP

A continuation of the NT software line, Windows 2000, while still not intended for the home user, signalled Microsoft’s intent for the line, introducing a new version of the Direct X that made it possible to play modern computer games using the system.

Windows XP was introduced with much fanfare in 2001, introducing the NT software line to the home market. XP introduced a raft of new features, including a new GUI, but was also notorious for its security vulnerabilities which triggered the rapid release of a number of “service pack” upgrades, dramatically increasing the security of the machine. At one point, before the service pack improvements were incorporated into the OS installation disks, it could be nearly impossible to download and patch in the security packs to a new XP installation before the computer became compromised by internet access. However, once the security wrinkles were ironed out, XP would prove a stable and popular operating system, accounting for nearly a third of desktop installations even today; something that may have driven Microsoft’s recent announcement that it will end update support for XP in 2014.

The inception of the smartphone OS

As phones became more complicated and more thoroughly integrated into users lives, they would require more complicated operating systems to manage the bewildering array of functions that had been absorbed from other mobile gadgetry. The early smartphone software such as Symbian still clearly owed a lot to earlier phone software like Nokia’s series 40, initially utilising keyboard interfaces and then eventually touchscreen, but still without the gesture recognition and multi-touch functionality that would come later.


1996 saw Steve Jobs return to Apple after its purchase of his company NeXT and in 1997, he successfully ousted CEO Gil Amelio and retained overall control. Jobs wasted little time in restructuring the company and introducing new candy coloured iMac’s. 2001 saw Apple’s next big innovation in operating systems, OSX. Built on NeXT’s UNIX based OS, OPENSTEP, OSX had a number of advantages over OS9, especially with regard to security and in running multiple processes, but for many people, the big change was the stunning new aqua desktop theme. Aqua’s soft edges, translucent colours, and high resolution icons made for a much more attractive user experience, something which would play well in the highly interactive environment of the new Apple stores.

The various updates of OS-X would remain the operating system of choice for Apple home computers to this day. Despite the success of OS-X, Microsoft’s stranglehold on the home and work desktop market would remain seemingly insurmountable. However, Apple would soon go on to open up another front in the OS war.

You got the touch!

2007 would see the launch of Apple’s iPhone to unanimous acclaim, along with Apple’s new iOS mobile operating system. Touchscreen displays had been used in products before, but the usability of the Apple device, along with iOS’ clever use of gestures and multi touch control, made the hand set a sensation. Despite the device’s high price, by October 2008 Apple had become the third largest handset supplier in the world. Although Jobs had initially steered development of the iPhone away from a larger tablet design, Apple would eventually go on to follow through its first stroke with the iPad. The modern tablet computer had arrived and it was here to stay.

Android - A new challenger enters the arena

August 2005 had marked Google’s entry onto the operating system battlefield with the acquisition of Android, a company which had been started in 2003 with the intent of making operating systems for cameras, later turning its attention to phones. While Google’s intent for the company had initially seemed unclear, 2007 saw this become clear with the announcement of the Open Handset Alliance, a consortium of phone manufacturers and other technology companies. Android was unveiled as an open mobile platform based on Linux. The first android device, the HTC dream would be unveiled less than a year later, soon supplemented by Google’s own Nexus devices and a bewildering array of offerings from other manufacturers.

Vista and Windows 7

Meanwhile back in the world of desktops Microsoft’s proud tradition of mismanaged OS launches continued with Vista, whose shiny new GUI improvements and increased security came at the cost of dramatically increased system requirements. A lot of computers sold as “Vista ready” performed poorly, especially when the company attempted to actually make the most of the new features of the software, leading to a backlash from customers left with poorly functioning machines. However, as the hardware caught up with software, sales started to improve. Windows 7, released in 2009 represented more modest changes after the big changes present in Vista, fine tuning the Vista functionality, and addressing performance issues. The next big change would come with the next and most recent iteration in the Microsoft family, Windows 8.

The OS finds its voice

Meanwhile, mobile operating systems continued to develop at pace with a wider and wider range of functionality incorporated. Of particular note, the future development of operating systems was first seen in Siri, a personal assistant and “knowledge navigator” with a natural language interface. Introduced first as an app, the functionality was soon integrated entirely into iOS 5 onwards as a major component and selling point for the later model iPhones and iPads. This technology is far from mature, and incompletely duplicated by some of the later copycat applications, most of which focus on aping the speech recognition aspects of the technology. But its purported ability to learn about the user represents intriguing possibilities for the future direction of our interaction with technology.

Windows 8 - the mobile OS writ large?

Divisive from the start, Windows 8 introduced probably the most sweeping changes to the GUI since the original version of Microsoft Windows. Windows 8 was intended to work effectively on tablets, touchscreens and hybrid devices, and shared many similarities with Microsoft’s Windows Phone mobile OS (Windows Phone 8 onwards would be directly based on the windows 8 software) effectively bringing the mobile and OS desktop into convergence. However, this left many desktop users, particularly those without touchscreens, unhappy. Microsoft inflamed the issue by refusing to include familiar features such as the button on the “metro” display or allowing users to easily default to the desktop. While many, including the author of this piece, feel that the software represents a step forward for Windows, the unintuitive nature of the changes, and the lack of transitional support provided left many casual users struggling.

The Future?

So what does the future hold for the humble OS? This is unclear, but what is obvious is that more radical changes are on the way. The unstoppable rise of mobile devices and tablet computers will continue to raise new challenges for software designers, particularly as even stranger interfaces arise such as Google’s new glass headsets. Voice control and AI interpretation of intent will become more and more important as direct input becomes increasingly difficult and less common. Tomorrow’s OS is likely to anticipate your needs rather than have to be asked. Of course for many people this may be a step to far, and it remains to be seen whether more and more people will choose to persist with more comfortable “retro” technology rather than embrace the future. Whatever happens, it is clear that we are now living in interesting times.