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OPS201 - Introduction to Operating Systems

1,668 bytes added, 02:15, 18 September 2023
A Brief History of Operating Systems
* 1976 - Microcomputers, 8-bit computers inexpensive enough to be purchased by individuals or small businesses, became widelyavailable. Digital Research's CP/M operating system became popular on Intel- and Zilog-based microcomputers.
* 1981 - IBM decided to enter the microcomputer market with the IBM PC. Needing an operating system, IBM contacted Microsoft - but their only operating system at the time was Xenix, and the IBM PC was not powerful enough to run Xenix well, so Microsoft licensed (and later purchased) a CP/M clone named 86/DOS (aka QDOS) from a local computer company (Seattle Computer Products). This operating system was used as the basis for Microsoft's DOS (disk operating system) product, named PC/DOS when marketed by IBM or MS/DOS when marketed by Microsoft.
* 1983 - The IBM PC was successful in the market, due to both IBM's marketing and the fact that IBM published the technical specifications which enabled other companies to sell compatible accessories, so IBM produced more powerful models including the IBM PC/XT (1983) and PC/AT (1984). These models had much larger amounts of RAM as well as hard disks, so Microsoft needed to update DOS with new features; they did this by incorporating some features from Xenix (their Unix version), including a heirarchical filesystem.* 1984 - Richard Stallman created GNU Project and the Free Software Foundation to promote the concept of Free Software ("free" in the sense of freedom, not free of cost).* 1984 - The X Window System is first developed at MIT to provide a cross-platform foundation for graphical user interfaces. It becomes widely used on Unix systems sold by many different vendors.* 1985 - Microsoft introducedWindows 1.0, which was used in conjuction with DOS. Windows provided a graphical user interface and multitasking (though both were initially very limited).* 1991 - Linux Torvalds, a computer science student in Finland, wrote and released the Linux kernel. The Linux kernel, combined with software from the GNU project and other free software projects such as the X Window System, made a useful operating system (often referred to as "GNU/Linux" or just "Linux").* 1992 - IBM and Microsoft ended their collaboration on OS/2, an advanced operating system with a graphical user interface. IBM continued independent development of OS/2.* 1993 - Microsoft introduced Windows/NT, incorporating some concepts from OS/2. Unlike previous versions of Windows which required DOS, Windows/NT provided a complete (and more advanced) operating system with a GUI and did not require DOS. All future versions of Windows were based on Windows/NT.* 2007 - A consortium of developers called the Open Handset Alliance, led by Google, releases the Android operating system for mobile devices. The Android platform is based on the Linux kernel.

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