Showing posts with label server. Show all posts
Showing posts with label server. Show all posts

What is Raspberry pi ?

Raspberry Pi also known as only Pi, is a SoC.

So what is a SoC ?

A SoC abbreviation for System on a Chip. It is actually a chip or an integrated circuit which has all of the components of a complete system integrated in it i-e: having attached on it.
    A SoC can have all the components a computer or any other electronic device can have, such as Processor, usually an embedded processor, GPU, memory, both permanent and temporary, i-e RAM, ROM, SSD, Flash memory. Additional memory can also be added using SD cards or External Hard disks. I/O units such as USB, HDMI, VGA etc. Networking parts like Ethernet, WLAN adapter. Other components like ADC or DAC, Voltage regulators, timers maybe found on a SoC.

Back to Raspberry Pi



The Raspberry Pi was developed in UK for educational purposes, but now has found many more applications. As described above, it is a SoC, meaning a complete working system with all required components on a single chip.
       It is not a processor, it is not just a chip, it is not a micro-controller, it is not an extension or upgrade for a PC. But what it is, that it is minicomputer. That's more like it.
     Till now it has two models. Model A and Model B. Model B offers more features than A. The above image is of model A.The below images are of model B, which looks something like this:



Features

The key features of Raspberry Pi are:

  • Embedded processor is ARM1176JZFS @ 700 MHz.
  • Video core 4 GPU, which is capable of Blue-ray quality playback, using H.264 codecs @ 40MBits/s.
  • Open VG libraries.
  • Open GL ES 2.0
  • 256 MB RAM in Model A. 512 MB RAM in Model B.
  • USB support ( Model B ).
  • HDMI support.
  • Ethernet for Internet connection.
  • GPIO ( General Purpose Input/Output ) pins Male connector.
  • 3.5 mm audio jack.

Dimensions

The measures of Raspberry Pi are 85.60 mm x 56 mm x 21 mm, or 3.37" x 2.21" x 0.83". It weighs about 45 grams.

What Operating System ( OS ) it has ?

It does not comes with an installed OS, as it does not has any storage device. It boots from a memory/SD card or a hard disk/ solid state, which has to be attached externally. While purchasing one, we can also choose to buy one SD/memory card which comes loaded with an OS, usually Raspbian( Debian Linux redesigned to be compatible with Pi ) or NOOBS setup ( an installer which gives a list of all supported and recommended OSs ). But if you don't want to buy an additional SD card, you can download the same OSs free from their official website, here. After downloading, you can use it with an SD card you already have.

Devices able to connect to Raspberry Pi

Nearly everything.

  • TVs, Monitors ( CRT, LCD, LED )
  • Headphones
  • All kind of Mobiles including, Android, Windows phones, i Phone/Pads/Pods
  • PCs, Mac and all other computers running Linux, Unix etc.
  • Head phones, Speakers, Microphones ( through audio jack )
  • Cameras, sensors
  • Keyboards, Mouse, Touch-pads
  • Printers, Plotters
  • And many more stuff of the kind

Where to buy ?

You can buy it from the official website. Or from here at element14. Or from here.

Many ways to use it 

It can be used in many many ways. Some of the uses are listed below:

  • As a media center for watching movies, playing songs, just connect it to your TV and use RaspBMC, an alternate OS similar to XBMC.
  • As a NAS ( Network Attached Storage ), or in other words, your own Cloud server.
  • Build Arcade machines.
  • It can be used to build Robots.
  • It can be used to build security systems.
  • A Tablet computer, by running Android on it.
  • To build a UAV
  • Make a land-line phone.
  • Make a Supercomputer.


That would be all. Hope you like it !

What is DNS ?

DNS stands for Domain Name System, not Domain Name Server. It is a protocol or a set of methods and actions which defines everything happening from the requesting of a webpage by a client, through the conversion of domain into IP address and the processes taking place in server, to the providing or redirecting of client to the requested webpage. It is a short and easy summary of DNS. But it should be noted that the files and webpages are not transferred by DNS, in fact only their addresses are transferred.

Steps involved in DNS


The Domain or URL

First the client or user requests for a webpage in a web browser. The syntax of URL or Domain which is entered in the address bar of the web browser is something like this:
A domain name consists of several parts called labels. The are separated by dots, such as www.rustedbyte.blogspot.com .
The right-most label is called top level domain. In the above example .com is the top level domain. The other labels to the left of top level domain are called subdomains or subdivisions of the top level domain.The subdivisions may be up to 127.
Any label may not start or end with a hyphen.

Conversion of Domain or URL into IP address

Through DNS, the Domain, web address or URL you have entered is converted into its IP address. For example, google.com has IP address : 173.194.124.39 .
  You can find out the IP address of almost any website by pinging. Just open command-prompt, or cmd.exe. And the use ping command, such as:
        ping rusted.blogspot.com
You can use the IP address to open a website by just entering the IP address into the address bar.

IP address gets transferred to server

The IP address gets transferred to a server, usually ISP's server. The server looks up for the IP address in its memory, if found then it will redirect the client to the server which is hosting the requested webpage. If not found then it will transfer the requested address to another server, if that server knows the address of the server which hosts the requested webpage, then it will transfer required info to the ISP's server.

Caching of the webpage's server's address

If the server which gets the clients request, already has the requested webpage's hosting server's address, then it will just redirect the client to the requested webpage. If not, the above step will take place. After getting the address from another server, the ISP's server will cache the address or store it in its memory, in case there are more requests for the same webpage.

Back to the client

The client gets redirected to the requested webpage.