[sn2710]

when we type in through keyboard .Does the data first go to physical memory and then cache and then cpu or is there a way wherein data can diretly go to cpu bypassing main memory and cache.Thanks in advance

[NovaX]

This is handled by terminal interrupts. I vaguely remember the process in Minux and found a good description for you.

[jwdonahue]

Depends on the system and CPU involved. Are you talking about a PC? In most cases there's at least two CPU's involved in getting the data from the keyboard to whatever program is the final destination. One little micro and/or ASIC in the keyboard that processes the switch array inputs and converts them to the appropriate signals on whatever kind of interface the keyboard uses to interface with the PC and then of course the main CPU in the PC itself.

From the perspective of an application hosted by an operating system, all inputs pass in via RAM buffers at some level.

[hiker]

sn2710: Please DO NOT cross post. This is the 3rd of the same post. It is also being responded to over here.