How is RAM able to acess any place in memory at O(1) speed

Question

We are taught that the abstraction of the RAM memory is a long array of bytes. And that for the CPU it takes the same amount of time to access any part of it. What is the device

Answer 1

I've been reading your comments and questions until I answered. I think you are on the right track, but there is some confusion here. The random access in which you are implying doesn't exist in the same way you think it does.

Reading, writing, and refreshing are done in a continuous cycle. A particular cell in memory is only read or written in a certain interval if a signal is detected to do so in that cycle. There is going to be support circuitry that includes "sense amplifiers to amplify the signal or charge detected on a memory cell."

Unless I am misunderstanding what you are implying, your confusion is in how easy it is to read/write to a cell. It's different dependent on chip design but there IS a minimum number of cycles it takes to read or write data to a cell.

These are my sources:

http://www.doc.ic.ac.uk/~dfg/hardware/HardwareLecture16.pdf
http://www.electronics.dit.ie/staff/tscarff/memory/dram_cycles.htm
http://www.ece.cmu.edu/~ece548/localcpy/dramop.pdf

To avoid a humungous answer, I left most of the detail out but all three of these will describe the process you are looking for.