PC architecture

[DungeonMaster]

Form what i have studied in school basic PC architecture is:

Northbridge->CPU, AGP bus, Memory
|
Southbridge->IDE, Raid, PCI, Comm ports etc...

I dont know why some times the CPU is bothered when copying data (like .vob files, that size i mean)? I mean, since theoretically the northbridge has nothing to do with this process, sometimes when copying large files i can see the CPU usage going @15%. It might be a strictly technical question but i am curious to know...

 

[Peter]

Er, it hasn't always been like that, and it's not going to stay like that either. It used to be that the north-south interconnect was PCI, the same PCI bus that drove the slots.
Now we're seeing the move of the RAM controller into the CPU, and the demise of the north bridge as the system's heart and core - degraded to a mere bus bridge (to AGP, PCIE and southbridge).

CPU load whilst copying? Guess who's managing the file system, translating file names to raw sector numbers, instructing the mass storage drives to read/write their media, setting up DMA engines to put data here and pick it up from there, copying data to and fro buffers in RAM, handling the "I'm done" interrupts from the drives and DMA engines etc. etc.? Yes. It's the Central Processing Unit. Who would have thought?