Subject: {FIRSTNAME}, What is an Operating System Hello {FIRSTNAME}, Thank you for subscribing to my operating systems ecourse! In this ecourse you'll learn all about: Part 1: What is an Operating System Part 2: History of Operating Systems Part 3: What an Operating System Does Part 4: Microsoft Windows Part 5: Mac OS Part 6: UNIX Part 7: Linux That being said... Lets get started shall we :) ================================================== Part 1: What is an Operating System -------------------------------------------------- An operating system – commonly referred to as an OS – is a set of computer programs that manage the hardware and software resources of a computer. The OS processes electronic devices with a rational response to commands that are approved by the system. At the foundation of all system software, an operating system performs basic tasks like controlling and allocating memory, prioritizing system requests, controlling input and output devices, facilitating the network, and managing files. The OS can also provide a graphical user interface for higher functions. Essentially, the OS forms a platform for other system software as well as application software. The operating system is the most important program that runs on a computer. Without an operating system, your computer would not work. It would not be able to process requests for print, simple calculations, or any other function. It is really the brain that runs the equipment. For larger system, the OS has great responsibilities than with a PC. In larger systems, the operating system is kind of like a traffic cop. It makes sure that different users and programs running at the same time on different systems don’t interfere with each other. It also acts as a security guard making sure that unauthorized users are not able to access the system. There are four classifications of a computer operating system. They are: -Multi-User: Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users -Multi-Processing: Supports running a program on more than one CPU -Multi-Tasking: Allows more than one program to run concurrently -Multi-Threading: Allows different parts of a single program to run concurrently Real Time: Responds to input instantly. General-purpose operating systems, such as DOS and UNIX, are not real-time. Operating systems provide a software platform on top of which other programs, called application programs, can run. The application programs must be written to run on top of a particular operating system. Your choice of operating system, therefore, determines to a great extent the applications you can run. For PCs, the most popular operating systems are DOS, OS/2, and Windows, but others are available, such as Linux. In any device that has an operating system, there's usually a way to make changes to how the device works. This is far from a happy accident; one of the reasons operating systems are made out of portable code rather than permanent physical circuits is so that they can be changed or modified without having to scrap the whole device. For more information about operating systems, please refer to my website Take Care,