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Re: respectful slightly dumb question about 64 bit computing.....

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On 10/29/06 07:22, Michael Fothergill wrote:
> Dear Debian folks,
> I have been reading about the benefits of 64 bit computing on the
> web. In the old days I used to run some molecular dynamics
> calculations on a DEC Alpha with a 64 bit chip in it and the
> developer there did get a definite boost from it.
> I have been reading the discussion on wikipedia about 64 bit
> computing. There is a little section in there that interested me
> and I wondered if I could ask a question about it.
> Here is the section:
> OK, here's the dumb question:
> Let's suppose that money was no object and we managed in some
> technical feat to construct a computer that could have a 64 bit
> chip in it that would be properly hooked up to 16 exabytes of
> RAM.
> If I had such a computer in my possession and I offered to donate
> to the Debian community how would it respond?
> Would it say

It would say,
1. How did you build that computer?  Current 64 bit chips do
   not have 64 bit address lines.

2. Why did you use a year's production of the world's RAM
   production for your own machine?  Now, no one else can
   buy a computer, and thousands of companies and millions
   of people have been put of of work!!!

> What sorts of problems would they be?  I suppose it could one
> that would require e.g. a huge database.

I don't think that the Intarweb is 16EiB.

Maybe if you aggregated every database in the world, including the
spy DBs from secret TLAs, Wal-Mart, Visa, every scanned document
from Soviet, PRC, US & EU archives, etc, you'd make a dent in 16EiB.

> The other question I have is:  how much performance increase in
> database applications is typicall seen using 64 bit computing?

A big difference.  The larger, flat address space means that
"low-end" systems with 32GB RAM are not rare (but not common...),
and big iron systems with 128GB RAM are definitely out there.  You
can cache a whole lot of data in that much RAM.

And with bigger disks, organizations  store lots more data, which
means you need bigger serial numbers, which means more frequent use
of BIGINT (8 byte) numbers.  Of course, 8 byte integers less
efficient on 32-bit systems, because it requires loading them into 2
registers instead of 1.

- --
Ron Johnson, Jr.
Jefferson LA  USA

Is "common sense" really valid?
For example, it is "common sense" to white-power racists that
whites are superior to blacks, and that those with brown skins
are mud people.
However, that "common sense" is obviously wrong.
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