Which Operating System Are You Using?

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You may work on or own different computers with different operating systems. Sometimes it may not be obvious which operating system is installed. If you want to install a new piece of hardware or software, for example, you will need to know this information. Here are some suggested ways to quickly determine which operating system is on your computer.

Macintosh System

To determine which operating system is running on a Macintosh system:

1. Close all applications. (Mac OS X can run Mac OS 9 within itself in order to support older applications; if you ask a computer in this condition what its operating system is, you may receive an incorrect answer.)
2. Click on the Macintosh icon in the top left corner.
3. From that menu, choose the About this computer option.

   Information about the version of the operating system and the hardware will be displayed in a pop-up window in the center of the screen.

Windows System

The simplest way to determine which Windows operating system is running on your computer is to click on the Start button, most often located in the lower-left corner of the screen. The name of the operating system is displayed to the left of the Start button.

For more detailed information about which operating system is running on a Windows system:

1. Right-click (click with the right-hand mouse button) on the My Computer icon. (By default, this icon is usually located in the top left corner, but it may be located anywhere on the desktop.)
2. From the menu that appears, choose Properties.

   Information about the version of the operating system and the hardware will appear in the General tab of the pop-up window that appears.

Unix System

To determine which operating system is running on a Unix system:

1. If you are using a command-line interface already, skip to the next step. If you are using a GUI, start a terminal window that communicates with the machine whose OS you would like to query.
2. Type the following command:

   uname -a

   The response you see will likely differ from the ones given here, but the general format of the response will be similar.

   In the case of a computer that responds with:

   SunOS staff3.cso.uiuc.edu 5.7 Generic_106541-12 sun4u sparc SunW,Ultra2

   you can determine the operating system, the machine name, the kernel patch level, and some hardware information:

   SunOS

   This first part of the text identifies the operating system. Other options include AIX, BSD, HP, IRIX, Linux, and several more. In this example, running uname -a returns SunOS.

   staff3.cso.uiuc.edu

   This part of the text identifies the machine name, which is assigned by the system administrator. It can be fully qualified (it can include network identification information separated by periods), as above, or it can give only the machine name (in this case, the name would be staff3).

   5.7 Generic_106541-12

   The information in this section identifies which version of the operating system is installed (possibly including kernel patch levels, as indicated by the 106541-12 number above). Other possibilities in this area of uname -a output include a listing of the date and time when the uname -a command was run.

   sun4u sparc SUNW,Ultra-2

   The last part of the line indicates hardware information, such as processor type. i386 is also a common value to see in this area. (AIX and HP machines do not commonly include processor information in the uname -a output.)

 

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