Bigtable: A Distributed Storage System for Structured Data

To be able improve applicability, scalability, performance and availability in data storage for large data, the authors have implemented and deployed a distributed storage system which is called Bigtable, and this would be the main motivation of the paper. To manage large data, the system provides a simple data model for dynamic control over data layout and format for clients as describe as following paragraph.

For their contributions, the authors have spent roughly seven person-years on design and implementation. They have introduced an interesting model which a map data structure, the concept of row and column families, and time stamps which form the basic unit of access control and so on. Also the refinements and the performance evaluation which describes in the paper have shown an improvement. Three of the real applications or products have success by using the Bigtable implementation and concepts.

The paper’s single most noticeable deficiency already describes by the authors in the paper which are the following. For example, consideration of the possibility of multiple copies of the same data doesn’t count; a permission to let the user tell us what data belongs in memory and what data should stay on the disk rather than trying to determine this dynamically. Lastly, there are no complex queries to execute or optimize. The Bigtable seems to take to another whole level of manipulating the data, however my question is still concerned about the networking such that it seems to me that the latency plays an important role to be able to retrieve or display the result of queries. In my personal opinion, there is still a bottle neck because it is a distribute servers which require a high-performance network infrastructure to achieve the highest performance.

I would rate the significant of the paper 5/5(breakthrough) because of the Bigtable model system is amazing such that it could adapts to handle some very large data, and it has been used in many popular application that we have been using nowadays, for examples, Google products such as Google earth and Google analytics and etc. The concept of adding a new machine when it needs more performance to perform database operations is spectacularly. I believe that the Bigtable will be very useful in future use, and we will most likely to see the next coming products from such companies take this model to approve their use of database.

Reference:
Bigtable: A Distributed Storage System for Structured Data, F. Chang, J. Dean, S. Ghemawat, W. Hsieh, D. Wallach, M. Burrows, T. Chandra, A. Fikes, and R. Gruber, Proc. of the 7th Conf. on USENIX Sym. on Operating Systems Design and Implementation, November 2006, pp. 205-218.

Serverless Network File Systems

Serverless Network File Systems, T. Anderson, M. Dahlin, J. Neefe, D. Patterson, D. Roselli, and R. Wang, Proc. of the 15th ACM Symposium on Operating Systems Principles, December 1995, pp. 109-126.

The authors believe that the traditional central network file system still has a bottle neck, such that all the miss read/write goes through the central server. It is also expensive, such that it requires man to control or operate the server to be able to balance the server loads. Therefore, they have introduced a server less file systems distribute file system server which responsibilities across large numbers of cooperating machines. Ideally, the authors have implemented a prototype serverless network file system called xFS to provide better performance and scalability than traditional file systems.

There are three factors which motivate their work on the implementation of the serverless network file systems: the first one is the opportunity to provided by fast switched LANs, the second one is the expanding demands of users and the last one is the fundamental limitations of central server systems.Taking about their contributions, the authors make two sets of contributions. Firstly, xFs synthesizes a number of recent innovations which provide a basis for serverless file system design. Secondly, they have transformed DASH’s scalable cache consistency approach into a more general, distributed control system that is also fault tolerant. Moreover, they have improved the Zebra to eliminate bottlenecks.

The paper’s single most noticeable deficiency is the limitation of the measurements, such that the workloads are not real workloads, and they are micro benchmarks that provide a better performance in term of parallelism than real workloads. Another limitation of the measurements is that they compare against NFS, hence scalability is limited.

This paper seems very solid and interesting to me, I like many ideas, for example, the idea of taking advantage of the cooperative caching to server client memory. However, I still have a question regarding to the future work and its limitation such that, what would be a real workloads the author most likely to measure on and how much expectation would the author prefer to see according to such workloads.

I would rate this paper 5/5(breakthrough) due to the challenging idea and how the authors implements and their measurements. It improves the old fashion server in term of performance, scalability, and availability. It could also help reduce the cost of hardware.

The Multics virtual memory: concepts and design

The Multics virtual memory: concepts and design, A. Bensoussan, C. T. Clingen and R. C. Daley, Communications of the ACM, Vol. 15, NO. 5, May 1972, pp. 308 – 318.

As we might know, the use of on-line operating systems has been growing as well as the need to share information among system users. However, they share by the use of segmentation. This motivated the authors, such that, in order to take advantage of the direct addressability of large amounts of information which made possible by large virtual memories, the authors are motivated to develop a Multics (Multiplexed Information and Computing Service) to provide a generalized basis for the direct accessing and sharing of online information. There are two goals; the first goal is it must be possible for all on-line information stored in the system to be addressed directly by a processor. Another goal is that it must be possible to control access.

Regarding to the authors contributions, the authors have introduced an idealized memory by using the segmentation and paging features of the 645 assisted by the software features. Also, to take some advantages of existing mechanism , the Multics processes and the Multics supervisor were introduced The symbolic addressing conventions technique also provide an ease of use for users, such that a user can reference a segment’s pathname and supplying the rest of the pathname according to system conventions. Moreover, by making a segment known to a process and improve the segment fault handler have given the Multics a lot of performance.

The paper’s single most noticeable deficiency is that there are too many assumptions, so it makes the readers pretty confused of how to use the features of the Multics. The conclusion of the paper should summarize what the authors have contributed and how to improve it in the future work, instead of showing of user and supervisor view points. It would be good if the authors emphasize of how the selection algorithm work. For the question according to the paper, I would like to know how much it improves from the old fashion of the concept.
Lastly, I would rate the significance of the paper 3(modest) due to the fact that this paper is published 30 more years ago. It lacks of experimental and compare/contrast with the use of segmentation.

How to make your own tissue box

Getting bored with the simple tissue boxes, here is how to make one of your own. The trick is all about drawing a tissue box outline, and use your toothbrush as your painting tool. I recommend you to work with water color. Mix the color as you like, cover the area with your toothbrush spreying techniques. Thats it! now you have your own cool tissue box. cake isn’t it? 🙂

How to use markers

Have you ever wonder how they come up with a colorful in most of cartoon books? There is a technique of how to draw them. The picture above is one of my portfolio shows you that I can draw exactly like the cartoon cover by using markers. The trick is that you need to work with gray shading markers. It looks like a poster color but its much easier to work on small details and user friendly.

Finally Full Scale :)

Almost two years of being an AT&T loyal customer, I have been suffered with low or no signal from my area. Its very frustrated so, I went to apply a new service today and yeah before I open a new account, I double check for a wireless signal strength for my area. Totally recemmend for anyone who is about to get a phone service to check the wireless signal first before sign up for an account.

7 Habits of Highly Effective People

I have been reading “The Seven Habits of Highly Effective People”, one of the books that my brother recommend me to read years ago, since I was 19-20, and I just finished reading the book today. Whew 🙂
I found the book quite interest and very useful for anyone who wants alternate way to improve or change his/herself. The book describes solid principle approaches to archive a personal effectiveness, and emphasizes of how important of the seven habits. To make the book shorten, I ran across many sites which gives a good summarize of the book as below.

http://www.leaderu.com/cl-institute/habits/habtoc.html

Oh, while I google the websites, I found a list of relevant topic about self-improvement which is written by John H. Patterson, interestingly, the list below he wrote is about 100 years ago, and still work effectively today.
Physically
1. Simple food, quality, quantity.
2. Regularity in eating and sleep.
3. Masticate; leave table hungry.
4. We are a part of all we have eaten.
5. Exercise, five minutes, three times daily.
6. Air — most important.
7. Sunlight, artificial light.
8. Water inside and outside.
9. Loose clothing.
10. Early to sleep; get plenty.
Mentally
1. Think sanely.
2. Learn from mental superiors.
3. Learn to listen attentively.
4. Read best newspapers and books.
5. Improve the memory.
6. Concentrate.
7. Don’t worry unnecessarily.
8. Be systematic.
9. Weigh both sides.
10. Avoid inferior minds.
Morally
1. Right is right, wrong is wrong.
2. Be truthful.
3. Ignore precedent if wrong.
4. Seek elevating recreation.
5. Don’t deceive yourself.
6. Learn to say “no.”
7. Live up to your principles.
8. Avoid temptation.
9. Form good habits.
10. Have a constitution.
Financially
1. Increase my earnings.
2. Decrease unnecessary expense.
3. Save money, U.S. Postal Bank.
4. Money makes money.
5. Invest — don’t gamble.
6. Make family budget.
7. Hard work.
8. Study the business.
9. Pay cash for everything.
10. Increase credit balance.
Socially
1. Avoid bad associates.
2. Select helpful friends.
3. Think alone.
4. Learn to be happy alone.
5. Family best company.
6. Work out, alone, my problems.
7. Avoid so-called society.
8. Entertain economically.
9. Stand well with neighbors.
10. Do some welfare work.