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SubjectRE: time_t size: The year 2038 bug?
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> > You are making his point, not refuting it. All these
> > things have moved to
> > 32-bits where they would previously have been done with 8-bit
> > or 16-bit
> > processors. They will likewise move to 64-bits.
> >
>
> you are missing the point.

No, you are missing my point.

> as stated before: embedded systems use the smallest, most efficient, most
> inexpensive chip that is up to the job.

I realize that this is common sense, but it's just not true. The defintion
of "the job" is depedent upon what chips are available. When the scope of
the embedded system is defined, it's based upon the current level of
technology.

Why did the Hubble, and embedded system, just get upgraded to a 486-50?
Obviously the system that was there before did the job, right?

No, what happened was the availability of more powerful embedded processors
changed the _scope_ of what the job was. This is what has _always_ happened.

And the amazing thing is that the fast chip will be less expensive. The
reason is simple -- the only significant difference in price between a chip
one generation back and a chip three generations back would be due to a
difference in pin count. And the chip one generation back will be suitable
for more tasks than the one three generations back. This higher volume will
often result in _lower_ cost.

In fact, it's hard to find non-specialized '286s in wide distribution now.
This is for an obvious reason -- it doesn't cost that much more to make a
'486, and the potential market is larger.

> 8bit chips are still used all over the place. And even in 38 years time,
> there will be plenty of tasks that can be done with a 32bit chip and a
> lightweight unix-like OS.

Yes, but you will find that they won't be.

> Why would you use a 64 bit chip if a 32bit would do the job?
>
> The 64 bit chip is bigger, so your device has to be bigger.

Why is that? The 64-bit chip can have an 8-bit external bus. And the 64-bit
will be made with leading edge technology, producing smaller dies.

> It will need a lot more power, so your device has to be bigger, needs more
> expensive batteries, needs (a larger quantity of) and/or (more expensive)
> ancillary components.. etc..

Not so. The 64-bit chip can run with a lower clock rate and still get the
same amount of work done, reducing EMI. Why will it need more or more
exensive ancillary compents? No law says the external bus implementation has
to be 64-bits.

> And finally, the 64 bit chip will itself cost a lot more than the 32 bit
> one.

Bull. The volume of the 64-bit chip will be much higher since it can do a
larger range of tasks. This volume increase may actually result in the
64-bit chip being cheaper.

> It's extra cost on top of extra cost on top of extra cost.

I don't believe it. Let me put it this way -- what's the current cost
difference between a '286 desktop and a '486 desktop? One is 16-bit, the
other is 32-bit. It's zero, basically. Why is that? Doesn't the '486 need a
more expensive bus architecture? Doesn't it need a more expensive processor?

> Granted there will be plenty of uses for 64bit chips in the future, but
> there will also be plenty of tasks suitable for 32bit chips...

Sure, but those tasks will be done by 64-bit chips even though they're
suitable for 32-bit chips. Everything will. It's the same reason I'm using a
P3-500 to write this email even though a '386 would suffice for the task. We
redefine the tasks to fit the available hardware.

DS


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