[rbanffy]

It was an 80's mainframe. I doubt power saving was one concern. We had folks typing forms in data-entry terminals 24x7 generating the tapes that were then fed to the bigger machine.

But you have an interesting idea. I wonder if there is any OS that changes memory distribution and allocation strategy according to desired power consumption on, say, portable computers.

The Linux kernel supports, IIRC, plug-and-play memory and processors and it could, conceivably (it it doesn't already) power up and down unused parts of the machine in order to reduce power consumption and heat dissipation. Even reads and writes to and from memory could be grouped in bursts if that could save power.

For instance, right now my running applications are within half of the memory, both cores are running slowly and the ethernet interface is disconnected. One memory module, one core and a network interface could be powered off without perceivable performance degradation. Also, as much data could be cached in the remaining memory so the disk could be powered down too or, and that would be interesting, spun at a lower speed.

Lots of interesting ideas in one lazy saturday afternoon. That's what I like in HN. :-)