We now continue our journey of big data technology having studied map produce and got started with a programming assignment last week. We now turn to distributed file systems, databases and most importantly, the emerging trends and directions which this technology is taking. I must warn you that, this week's lecture is rather broad, covers a lot of ground, and, is pretty scarce on deep detail examples. We're, we're just covering too much this week to afford too many examples. This week's lecture is therefore, much more of a high level overview of where big data technology came from and where it's going, will be very useful to graduate students. But, might leave some of you who don't have a strong background in operating systems, databases, etc., behind a little bit. But, I'm sure many of you will learn a lot and derive some fundamental insights into what big data is all about what the fuss about the technology is. At the same time, don't be disheartened if you start getting left behind because of a lack of, understanding of how database technology works. But, bear with me and pick up whatever you can from this lecture, which I think, really reflects my understanding and insight after talking to many people who are leaders in this field today.