Numeric IP

Tags

dns, dns server, ip, ip to number, number

Recently, I was going through some code and found something strange (??? !!!) In short, In one place they were passing an IP address and on the other place they were using it as an integer.. I didn’t understand what is happening and then I searched the internet and found something that explained it..

For those who may not know, IP address is the identity of a device in a network. Like your postal address. And each IP is of the format X.X.X.X and each segment (indicated by X) is an octet. And the values of each octet can be from 0-255. Each IP address can be converted into a single number using the formula:

4th octet * (256 ^ 0) + 3rd octet * (256 ^ 1) + 2nd octet * (256 ^ 2) + 1st octet * (256 ^ 3)

This will give a number and that number is the actual address for a server/machine in network.

For ex. 216.58.218.206 is the IP of google.com and as per formula

(206 * 256 ^ 0 + 218 * 256 ^ 1 + 58 * 256 ^ 2 + 216 * 256 ^ 3 = 3627735758 )

If you try http://<number&gt; like http://3627735758 in your browser, you can still access the server.

Additional info: When you type google.com in the browser (or any other site’s address for that matter), the request will be sent to a server. That server will have the information saying google.com is this IP and send the request to that IP. These servers are called as DNS (Domain Name Servers) servers.

Hello!!! Wake up computer!!

Tags

automaticallly wakeup, hibernate, Linux, rtcwake, sleep, standby, suspend, wakeup

Recently, I was looking for some possibility on whether I can put my computer to sleep and wake it up when I want it to..

While doing so, found this URL: In short, you can put it to suspend or hibernate and wake it up after some time:

rtcwake -m disk -s 60

There are different options to make it to suspend/hibernate/standby… and can specify the time to wake up.. Refer “man rtcwake” for more.

Its cool when you want your computer to wake up before you and have everything setup when you look at your computer for the first time in the day 🙂

Future of Software Developers

Recently, I attended a Java training. We have done all of the exercises in our college days itself. But, we used loooots of new stuff. We write abstractions over our code. They have some abstractions.. There are more abstractions over the previous ones.. For example: We have SQL/JDBC (Low level). We have hibernate and that is an abstraction over this. And JPA is another API that can provide an abstraction over hibernate..

On looking at things, I get a feeling that: After 5 years, there will be only two kinds of software developers. One who create abstractions, and the other, consumes abstractions. The consumer’s fate will be:

* After 5 years, No Java developer will know what is “new” operator

* After 5 years, Nobody will know how to write SQLs..

* After 5 years, Nobody will know how things actually work.. What happens behind the scenes…

* After 5 years, Companies will hire people with more memory power rather than their abilities.

And after 10 years, they’ll be just like some electricians who doesn’t know how things work. Only, knows how to assemble things.. If something goes wrong, the response will be, replace this with a working one…

After 20 years, people will not know what is going on.. how to debug issues.. why things are happening the way it is happening.. All these due to these levels of abstractions.. Finally, one fine day, they will say, Lets start writing our own SQLs and our own code…