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Showing posts from December, 2012

REDIS

When somebody asks us to create a web application, the software requirements will be Apache, Mysql, PhP(LAMP where L stands for Linux). Imagine an application which stores data in main memory instead of disk, this will increase your application performance tremendously. One such application is Redis. Redis stores data on memory instead of disk and will periodically sync with the disks(if necessary).
Why Redis?: Redis will be faster as it keeps data on memory. I read somewhere Memory is like disk and disk is like tape for redis.Redis allows lot of data structures. Basically its a NOSQL database(http://en.wikipedia.org/wiki/NoSQL) . They dont support table or database schema we use traditionally. For them everything is key value pair as in hashmap. Redis allows a key to have values of types- string, set, sorted set, list, hashmap. To understand each data structure and the command they support, have a look at http://simonwillison.net/static/2010/redis-tutorial/Lot of  web apps will be eas…

Creating own Hosting Space

Requirement: A Computer connected to DSL  modem and access rights to DSL Modem's admin interface.
In this setup, if I connect to a website, the request reaches the Modem. All systems behind modem will have private ips(say 192.168.x.x). The modem performs a NAT and sends the request to the ISP's upstream router. The modem will have a different ip on ISP's upstream subnet. So it puts its IP and some port translation so that it can map to same computer.
A very very rough sketch at http://drawit.eskratch.com/fetch?q=464041803 where A and B are clients who send requests to web servers on port number 8140 and 8141. Modem m receives them and translates req to m:80 and m:81 respectively and sends to the ISP modem.The ISP modem associates a public IP pub to the modem m and sends the request to webserver. On return the packet reaches ISP who based on IPmapping sends the data to modem m. The modem m based on port mapping, send the data to corresponding computer.
Now my requirement is…

Summarize-II

I talked about my summarization tool in the previous post.  I have pushed the source code in  github https://github.com/kalyanceg/summarize . Its completely undocumented. Probably I will add a javadoc for all methods and classes in a couple of weeks. If somebody wishes to contribute to the codebase or build over the existing utility, feel free to checkout the repository and it will be good if you push the changes (productive ones) back to the repo.