From the developers view these Linux based systems are pretty much general purpose computers.
However what mostly counts for the definition of "embedded system" is the end users view. The end user (customer) gets a complete system for a specific purpose, he can't install any own applications and partly can't even update the system.
A specialized or dedicated computer used to control devices (such as automobiles, home and office appliances, handheld units of all kinds, etc.) where the operating system and application functions are often combined in the same program. An embedded system implies a fixed set of functions programmed into a non-volatile memory (ROM, flash memory, etc.) in contrast to a general-purpose computing machine. However, sometimes single board computers and rack-mounted computers are called “embedded computers” if used to control a terminal interface, machine, motor, etc. An embedded device or system may contain more than one operating system and/or processors (microprocessor, microcontroller, etc.). Specifically excluded from this definition are all types of enterprise computing machines deployed as general-purpose computers (i.e., desktop PCs, standard laptop PCs, enterprise servers, etc.). Our definition of embedded system/device is intended to give a good indication of the potential operating system and run-time software royalty opportunity within the embedded systems market.
So there you go. As you can see our definition has grown substantially over the years as the embedded and IT/enterprise markets have converged. It's much more helpful to think in terms of vendors though.
Traditional embedded silicon vendors include NXP/Freescale, Renesas, Microchip, Rockchip, Cypress/Broadcom etc. Traditional embedded OS vendors include Wind River (Intel), Green Hills, Express Logic, Enea, Micrium, etc.
Intel/Samsung/TI and Microsoft attribute small portions of their revenue to embedded systems, but they don't show up often in conversations with embedded vendors in their respective markets...they focus on enterprise servers/computers/software so they are usually less relevant to the day-to-day going ons of embedded vendors (until they swoop in with the intent to acquire).
This is changing though...has been fun advising some larger players on embedded strategies. Interesting time to be in the market for sure.
Um, what? Pretty much every chip TI makes goes into either an embedded or softwareless system. Analog, mixed-signal, and DSP have been their bread and butter for decades.
Has your thing got always-on sensors, or actuators, or both? Your job title is probably "embedded software developer."