Mike Foss wrote:
"mike" wrote in message ...

Mike Foss wrote:

"mike" wrote in message ...


wrote:


mike wrote:



Supply and demand.
If your watch kept bad time, you'd send it back.
If your computer keeps bad time, you'll reset the clock
and bitch about it on the internet.


I'm looking for a techical explanation.


Very often, the economic or political considerations
dwarf any technical consideration.
The technical explanation is that they do what's cheap.
Wishing for a grand technical reason won't make it so.
mike


You seem to be saying curiosity is a worthless trait.

Nope, I'm saying insisting on technical explanations for economic
decisions is a worthless trait.
Anybody with a wrist likely understands that it's possible to keep
accurate time. If computer users rated it high in their purchase
decision, you'd see very accurate clocks.


File that one under D for DUH.

The OP was asking for a technical explanation, and so far the
responses have been enlightening. Well, except for yours.


There is no technical explanation except that the technology that
is being used does not guarantee accurate clocks.

If you do the math, you'll uncover the fact that a wris****ch is
phenomenally accurate compared to a RTC crystal.

I haven't been responsible for a computer design since 1989. Back
in the day, the philosophy was, "design for the center of the
statistical distribution and fix it in software."
Fortunately, UINX was smart enough to do time correction.

I haven't been responsible for a frequency counter design group since
1975. Back in the day, the philosophy was, "use the cheapest timebase
that guaranteed the specified accuracy."

I've had motherboards where they saved a nickel by leaving off the two
caps on the Xtal. Adding the caps helped, but "net time" fixed it in
software.

Are we seeing a trend yet?
You can get any accuracy you're willing to pay for. Computer users have
voted with their wallets for "lousy". I don't remember ever seeing a
specification for real time clock accuracy on a motherboard.
So if the clock ticks, it's in spec. Statistically, you'll sometimes
get one that's unacceptable and some of those will get bitched about on
the internet. It's the same reason that sometimes your Ford won't run
right.

You're the Chinese engineer. Go tell the bean counter that you want to
add 20 cents worth of parts to adjust the clock frequency, add $4000
worth of capital equipment to each production station, a week of
additional production line time to setup and program the equipment,
30 seconds of operator time to each board test and decrease the overall
yield.

It really is all about the Benjamins.

Let me restate it in technical terms. You get what you pay for, if
you're lucky.

And yes, my motherboard keeps very good time (but still not anywhere
near as good as my wris****ch). It's not because the design is
different from any other motherboard design. It's because all the
variables conspired to keep good time. I got lucky.

Benjamins!!!

mike

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