[ale] New Sharp Zaurus kicks a$$

[John Mills]

On Tue, 18 Dec 2001, Keith Hopkins wrote:

> Stephen Turner wrote:
> >whats the diff between normal i386 linux and embedded?
> >i dont understand the meaning of embedded.... 

> embedded as in a dedicated system with specialized i/o.  usually there 
> is an alternative format kb, or no kb at all, and video is quite often 
> non-existant or limited to 3 or 5 line lcd displays.  quite often they 
> use serial (rs-232, rs-422, etc) or analog interfaces as their only i/o.

<SOAPBOX>
My 'common sense' definition has always been "programmed function the
user does not perceive as done be a computer", which pretty much equates
to Keith's 'specialized i/o'. Some embedded applications - routers and
networked printers for 2 examples - pretty much resemble general-purpose
computers running mostly daemon processes and device-drivers. (Glossing
over a 'world of hurt' here, naturally!)

At the other extreme, you can pack a surprising amount of function into
(say) a PIC processor, some RAM, and a couple of I/O drivers. Can fit into
@#$!! little real-estate, too.

Products like wristwatches and kitchen timers are my 'low-end' examples.
These are only Linux application candidates for those with something to
prove, I would say.

<HOBBYHORSE>
One practical distinction [IMHO] is that the embedded code I've worked on
is much more tightly coupled to its execution hardware, often including
assembly language and direct hardware I/O. This makes it hard to integrate
with school curricula where you would like to convey general principles.
My opinion [again] is that general principles are always involved, but you
are expressing them in an application-specific way.
</HOBBYHORSE>
</SOAPBOX>

Regards -
 John Mills
 Unemployed Embedded-Systems Engineer


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