Whip a duo-core PC into submission...?

Rune Allnor wrote:
> But if you want to access that space in a random manner you
> need a signed integer type as pointer offset. If you don't
> have the signed offset, you don't have *Random* Access Memory
> but *Sequential* Access Memory. Or whatever the correct term
> might be.
>

Well, "random" just means that I can do anything I want and "sequential" 
means that I have to run along the memory space in order to "get to" the 
data I want - like tape or a segment of a CD or HD or....  Obviously these 
latter devices are a hybrid because they can jump to a zone - which is what 
RAM does is allow you to jump anywhere all at once.  Paged memory may be a 
counter example in some sense.

This isn't about how you generate the addresses, it's about how the memory 
is accessed once the address is available.  Consider this:  I write a 
program that will read memory randomly.  This is done by stringing together 
a bunch of read instructions with their addresses generated by a random 
number generator.  And, I'll just use all 32 bits for these addresses and 
not worry about who is using any part of memory because I'm just reading. 
This is probably a really bad description of how it would work in code 
because I'm not much (er...any)  good at x86 ASM but I hope the point is 
made adequately.

Dale's comments are helpful to me because he understands this better.

But, I wonder if part of your concern is how many instruction cycles it 
takes to generate an address?  That's a reasonable concern.  Generally I 
guess folks work with an instruction counter and the processor helps in 
doing this in the background for "free".  So, going to the next sequential 
address is "free".  But that's a speed issue and not a memory space issue I 
do believe.

Fred 

"Fred Marshall" <fmarshallx@remove_the_x.acm.org> writes:

> Martin Thompson wrote:
>> You can (under windows) use the task manager to assign a process to a
>> particular core, but I'm not sure that's your problem.
>
> Martin,
>
> Ah!  I see how one can set "Affinity" of a  process to cores in Vista 
> Ultimate at least.....  Does XP do this as well?  Home?  Pro?

Certainly XP Pro does here at work.  I haven't tried it under a "Home"
system ('cos my "home" system runs linux :)

Cheers,
Martin

-- 
martin.j.thompson@trw.com 
TRW Conekt - Consultancy in Engineering, Knowledge and Technology
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