Handheld computers such as the Palm and Windows Mobile all use versions of embedded operating systems that are stored on an internal memory chip rather than a boot from a disk.
What Is an Embedded OS?
An embedded operating system is essentially a stripped-down operating system with a limited number of features. It is typically designed for very specific functions for controlling an electronic device. For example, all cell phones use an operating system that boots up when the phone is turned on. It handles all the basic interface and features of the phone. Additional programs can be loaded onto the phones, but they are typically Java applications that run on top of the operating system. Embedded operating systems can either be custom-written operating systems specific to the device or one of the myriad general-purpose operating systems that have been modified to run on top of the device. Common embedded operating systems include Symbian (cell phones), Windows Mobile/CE (handheld PDAs) and Linux. In the case of an embedded OS on a personal computer, this is an additional flash memory chip installed on a motherboard that is accessible on boot from the PC.
Updating Embedded Operating Systems
Embedded operating systems may be upgraded if the chip they’re stored upon is flashable. For example, your home Wi-Fi router contains an embedded operating system; when you download new firmware, you flash the chip in the router with an updated version of the operating system. Some embedded OSes aren’t upgradeable by design. For example, in some automated teller machines, some components cannot be upgraded as a security precaution against tampering.
