.SYS File Extension

File used by Microsoft DOS and Windows operating systems; contains system settings and variables, as well as functions that are used to run the operating system; commonly used to store device drivers and other core Windows functions.

Some examples of SYS files include the following:

• IO.SYS: stores the default DOS device drivers and the DOS initialization program; used by DOS and Windows 9x.
• MSDOS.SYS: contains the core operating system code for DOS, known as the DOS kernel.
• CONFIG.SYS: contains the primary configuration information used by DOS.

Device driver used by Motorola cell phones; allows the phone to communicate with computer and transfer files to and from the device; typically installed with the software installation CD included with the cell phone.

Example Motorola driver files include the "m56pci.sys" device controller and the "p2k.sys" file, which enables the P2Kman program to upload and download files from Motorola Vxxx cell phones.