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OPS201 - Introduction to Operating Systems

67 bytes added, 09:07, 18 October 2023
A Brief History of Operating Systems
* Before the mid-1960s: A number of different manufacturers produced various computers for business. Since these machines were expensive, and because there were many different manufacturers, a relatively small number of machines of each model were produced. Very little was standardized, and data was rarely interchanged between computers. Consequently, there were many different operating systems, each with a fairly small market.
* 1964/1965 - MIT and partners begin the Multics Project. This project introduced many concepts that became common in later operating systems, including a heirarcical filesystem, multitasking, and interactive operation. This project continued through 2000. However, Multics was a fairly resource-intensive operating systemand ran only on very specific hardare.* 1969 - Bell Labs decided to end their participation in the Multics project. Dennis Ritchie and Ken Thompson, Bell Labs employees who were familiar with the Multics project, decided to implement some of its features in a much lighter-weight operating system, which they called Unix. Unix was soon rewritten in the C language, and could be fairly easily ported to other types of computers.
* 1970s - Unix continued to grow in popularity. Many computer vendors licensed it and adapted it to work with their computers; some of these variants included Xenix (Microsoft), AIX (IBM), Ultrix (Digital Equipment Corporation), HP/UX (HP), and many others.
* 1976 - Microcomputers, 8-bit computers inexpensive enough to be purchased by individuals or small businesses, became widelyavailablewidely available. 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.
* 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(for "New Technology"), 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.* 2001 - Apple releases released MacOS, a Unix-like operating system based on the "Darwin" kernel* 2007 - A consortium of developers called the Open Handset Alliance, led by Google, releases released the Android operating system for mobile devices. The Android platform is based on the Linux kernel.
== Anatomy of a Command Line Interface (CLI) ==