An SDRAM consists of multiple banks, we have to "open" one row in bank at a time for reading and writing and then "close" it by doing precharge. I am trying to understand how it all comes together and will be very thankful to anyone answering these questions:

1. Is there a difference between the term page and row? Why use the word page?
2. Is there a time limit to how long we can have a row open?
3. Once row is open can we read/write every column in any order while following the proper read/write cycle for that SDRAM?

4. Since SDRAM has to be refershed, does having a row open prevent us from sending commands for refresh?
5. Do we usually send refresh commands periodically e.g every 15.625us or in burst for all rows at a time?