An operating system (OS) manages computer hardware and software resources and provides common services for programs. The document discusses three main types: Mac OS, MS-DOS, and Windows OS. Mac OS was developed by Apple starting in 1984 and uses a graphical interface. MS-DOS was an early operating system for personal computers developed by Microsoft using a command line interface. Windows OS also uses a graphical user interface and was developed by Microsoft building on MS-DOS, with the Start menu and taskbar debuting in Windows 95.

1. Operating
Systems
An operating system (OS) is system software that manages computer
hardware and software resources and provides common services for computer
programs

2. Types:
 MAC OS
 WINDOWS OS
 MS-DOS

3. MAC OS
 MAC-OS stands for Macintosh operating systems
 The old Macintosh Operating System (Mac OS) is a non-Unix program that allows
a Macintosh computer to operate and be used. Mac OS was first made by Apple Inc. in 1984. In
those days Mac OS was called Macintosh System Software – which was shortened
to System or SSW (System Software). The term "Mac OS" first appeared in the splash screen for
System 7.5.1, but was not adopted as the new name until the release of Mac OS 7.6.
 MAC-OS is a series of graphical operating systems developed and marketed by Apple Inc.
 At macOS's core is a POSIX compliant operating system built on top of the XNU kernel, with
standard Unix facilities available from the command line interface.
 Version 10.14: "Mojave"[change | change source]
 Released on September 24th, 2018. One of the most visible features is system-wide "Dark Mode"
(UI theme with dark background).

4. MS-DOS
 MS-DOS stands for Microsoft Disk Operating System.
 is an operating system for x86-based personal computers mostly developed by Microsoft.
 MS-DOS was the result of the language developed in the seventies that was used by IBM for its
mainframe operating system.
 American computer programmer Timothy Paterson, a developer for Seattle Computer Products,
wrote the original operating system for the Intel Corporation’s 8086 microprocessor in 1980,
initially calling it QDOS (Quick and Dirty Operating System), which was soon renamed 86-DOS.
 MS-DOS uses command line interface to interact with the software

5. WINDOWS OS:
 Microsoft Windows is a group of several graphical operating system families, all of which are
developed, marketed, and sold by Microsoft.
 Windows uses GUI(Graphical user Interface) as its interface to interact with the system.
 The Start menu and taskbar as we know them in Windows today debuted in Windows 95.
 The Start menu and taskbar represent the main interface through which you interact with Windows
and your applications, and they've been subtly improved over the years to the extent that they've
become very powerful, useful and customizable.
 With each new release of Windows, new features have been added: integrated search, pinned
applications, recently used files and one-click access to often used folders and system
configuration tools