On Wednesday 02 November 2011 01:56:13 Linda McLeod wrote: [snip] > Why is there RAM..? Why can't the OS > run its RAM off'n the hd..? RAM exists because I/O of a HD is waaay too slow. You can get a feeling just how slow it can get when you open too many apps simultaneously, thus exhausting available RAM and making the OS use the swap partition for extra memory. It's *painfully* slow, the machine becomes practically unusable, and it's a complete waste of cycles of today's fast processors. Even the I/O of RAM itself is fairly slow compared to the typical modern processor. That's why processors now have a built-in cache (which is basically a smaller amount of RAM on the processor chip itself), in order to speed up execution of programs and calculations. You might then ask "why the processor designers don't put all RAM on the chip?" Because it would be too big, geometrically. In order to make the processor work on a 2GHz frequency or such, the chip surface must be small enough to keep everything in working conditions. Otherwise you run into out- of-sync problems, uneven heat and voltage distribution problems, and all sorts of stuff that would make the processor fail. So the bulk of RAM must be separated, on their own chips, and communitace with the processor via the motherboard, which is again quite slow, due to its size and other reasons. HTH, :-) Marko -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
