Jeff Bier’s Impulse Response—Application Processor—Say What?

Submitted by Jeff Bier on Wed, 07/23/2008 - 16:00

Recently I wrote about how the term “DSP” seems to be losing its cachet, and people are starting to use terms that are more application-specific. Instead of “DSP processors,” there are now “digital signal controllers,”  “multimedia processors,” and “video processors,” for example. These terms are fine with me.  But there’s one that really annoys me: “application processor.”

“Application processor” is the term used for the processors in cell phones that do stuff other than the actual cell phone connectivity. The “application processor” runs the web browser, for example, or the digital camera, or the navigation software. Sometimes the “application processor” is a separate chip, and sometimes it’s on the same chip with the baseband processor (which is the processor that does handle cell phone connectivity). A typical application processor has an ARM CPU plus various programmable and/or fixed-function coprocessors for graphics and multimedia tasks.

Now here’s what drives me crazy about the term “application processor.”  All processors are “application processors”—I’ve yet to see a processor that doesn’t run an application.  So the term is ambiguous (and silly) from the get-go.  One can argue that there are relatively few people in the world who design cell phones, and they all understand what’s meant by an “application processor,” so there’s no real ambiguity there. OK, I guess I’ll buy that.  And I do see that the term distinguishes this kind of processor from the cell phone’s baseband processor.

But now, “application processors” are branching out and finding their way into lots of things other than cell phones.  These include, for example, the Ford Sync “voice-activated mobile phone and digital music system for your car,” portable navigation systems, portable media players, etc., etc.   Given that “application processors” are now being used for a wide range of applications (they’re candidates for pretty much any type of portable device that has multimedia functionality and needs to balance performance, cost, and power), the term “application processor” is causing much confusion.  Many system developers are uncertain whether “application processors” are suitable for their specific applications.

Maybe “multimedia processor” would be a better choice.  But wait—as I mentioned earlier, there are already multimedia processors!  There are also “multimedia applications processors.” And “mobile multimedia processors.”  There’s no standardized terminology here, but at least these terms give you a hint about what the processors are useful for. “Application processor” doesn’t.  It’s a useless term, and it’s time to make it go away.

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