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No, it is accurateNo, it is accuratePosted Sep 1, 2004 15:40 UTC (Wed) by gallir (guest, #5735)In reply to: No, it is accurate by jonth Parent article: Cell Phones: Don't Count Linux Out (Business Week)
Why hard realtime is needed for small phones but not needed for smart
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No, it is accurate Posted Sep 1, 2004 15:58 UTC (Wed) by bronson (subscriber, #4806) [Link] Of course it's needed for the complex ones. It's just that with a $400 phone, you can afford to add a dedicated subsystem to handle the realtime tasks. With a $20 phone you can't.
No, it is accurate Posted Sep 2, 2004 12:13 UTC (Thu) by jonth (subscriber, #4008) [Link] Correct. Most "Smartphones" have at least two main CPUs, often referred to as the modem processor and the applications processor. (I'm ignoring any DSPs here).
The modem processor contains the physical layer and the protocol stack, with a simple driver interface (often just an AT interface). This processor almost always runs a pure RTOS, and will be a very low power device with a small memory footprint (a few 100KB RAM and 1-4MB Flash) and not much grunt (10s of MIPs).
The applications processor then looks after the user facing stuff. This runs Windows/PalmOS/Linux - or whatever, and is usually much more grunty (100s of MIPs) with oodles of RAM (10s of MB) and Flash (10-100s of MB).
In a "Vanilla" phone, the applications processor is dropped and a simple UI is put on top of the protocol stack on the modem processor, so this processor can usually drive a small keyboard and display.
cheers,
Jonth
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