Operating Systems
IntroductionAn operating system (OS or O/S) is the software responsible for coordinating and managing the movement and processing of data on a computer. The O/S allows the user to access application software, such as a word processor, using hardware like a mouse and keyboard. The application software also requires the O/S in order to access hardware such as the disk when it is writing to memory. Without the O/S, the elements of a computer would have no way of communicating with each other and nothing would get done. When an application is asked to start, the O/S will allocate RAM, meaning it will set aside space in memory for the application to run then start the application running. [1] Having an operating system means applications do not have to know how hardware works in order to use it. Much like we don’t need to know how a car engine works, just that it will do what we ask when we turn the key or press the brake.
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...by studentsThere are several great features of Linux; it is a free open source O/S which has both a command line and graphical interface. It also supports several programming languages which can be installed quickly and easily. There’s even the enjoyable command ‘apt-get moo‘. However my personal experience with Linux at the U of M has resulted in more frustration than admiration. For a second year class I had to Shell into a Linux lab on campus to edit and hand-in homework. This required me to enter commands one by one into the command line which also meant remembering a list of commands to get anything done. Several times I would forget the correct sequence of commands or move myself into the wrong directory looking for a file and have to start over from the top. After some time, it was pointed out to me that you could also edit files elsewhere and just transfer them in. It was so comforting to be reunited with the Windows style of clicking pictures and words to get what I needed. |
Why You Need an Operating System
Software outlines a list of specifications, including memory needed and the operating system(s) which it needs to run properly. However, computers that satisfy these specifications can still have several differences in hardware, including the amount of memory available, the processor speed and even the kind of mouse, keyboard and printer you choose to use. At the same time, we can all buy the same boxed software which is mass produced and isn't meant to be modified. The O/S will make sure that the software will be able to communicate with whichever hardware is on your computer. An O/S has two faces; one faces you and applications and the other faces the internal hardware[2].
Types of Operating Systems
Different types of operating systems are designed based on the types of applications to be run and who will be using the computer.
- Real-time operating system (RTOS) - The RTOS has very little user-interface because the user doesn't need to input much information. Instead, it is designed to perform a few particular tasks. The RTOS must run each task in the same amount of time each time it is run. Used in machinery and household appliance controllers such as a programmable thermostat.
- Single-user, single task - Designed so one user can do one task at a time. The O/S doesn't have to worry about managing memory or hardware across different applications. A good example is the Palm O/S in Palm handheld computers.
- Single-user, multi-tasking - A user can run several applications at the same time with each application getting access to the hardware it needs. For example, as you are reading this Wiki, you may also be running a music program or checking Facebook at the same time. This is the most common O/S as it appears on most laptop and desktop computers.
- Single-user, multi-tasking - A user can run several applications at the same time with each application getting access to the hardware it needs. For example, as you are reading this Wiki, you may also be running a music program or checking Facebook at the same time.
This is the most common O/S as it appears on most laptop and desktop computers.
- Multi-user - Several users can access applications at the same time. The O/S manages the computer's resources so each application gets a fair share of the computer resources.
Operating Systems are also grouped by their method of interacting with the user, known as the interface.
- Command Based - The user must remember several commands and type each command on the keyboard as needed
- GUI Based - GUI is a graphical user interface which is more familiar and easier to use. The user makes requests using the mouse in a point-and-click style. This is how most systems appear to the user.
The retail sales obtained by the following brands or companies contribute to almost all operating systems found on machines today.
- Windows by Microsoft - 90% of computers
- Mac by Apple - just over 8% of computers
- Linux - a collaborative effort, 0.71% of computers
The remainder is made up of several other operating systems or modifications of those listed above such as those found on Sony's Playstation and the Nintendo Wii[3]
These percentages were calculated in October of 2008.
Further Readings
- How Stuff Works Learn how specific operating systems work, such as Windows Vista. Also find more information on the history and future of operating systems.
- Computer Hope Important definitions and news from Apple, Microsoft and Linux/Unix
References
- ↑ COMP 1260 Course Notes Fall 2008 http://www.cs.umanitoba.ca/~comp1260/Notes/02_whatis08c.pdf
- ↑ An Illustrated Guide to Operating Systems http://www.karbosguide.com/hardware/module6c2.htm
- ↑ Market Share by Net Applications http://marketshare.hitslink.com/report.aspx?qprid=8
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