RAID basics

What is RAID:

RAID stands for Redundant Array of Independant Disks previously known to be Redundant Array of Inexpensive Disks. First to explain RAID - what is it and what is it used for, let me clear you what does physical and logical drives in a computer system means.

A physical drive signifies the hard disk inside the computer cabinet. The physical part of the computer. It may be one or two in number.i.e., the physical drive is the real one as you see it inside the computer as a part of it.

In contrast, a logical drive is that which is a virtual representation of your physical drive. It is the drive(s), as seen by the operating system of your computer system.

An example might clear the cloudy thoughts about the physical and logical stuff concerning drives. Consider an  example, of a laptop, it has only one hard disk inside it, but when you partition it, such as C:, D: etc., now, the original drive inside the laptop is the physical disk and the C:, D: are called logical disks. I mean if you have four partitions, and one hard disk, you have one physical disk, which is divided into four logical disk... Now i think it will be clear that the logical disk is nothing but the physical disk as seen by the operating system.

Comming to RAID, it is the technology used to deploy the hard disks for increased storage and or or redundancy. Here R signifies redundant which means backup or duplicating. Here in RAID, we use two or more physical drives, and use RAID configuration to make the operating system believe that there is only one hard disk.(i.e., logical drive) many configurations are available in RAID such as RAID 0, RAID 1, RAID 2, RAID 3, RAID 5 etc... let me introduce RAID 0 and RAID 1 which will suffice the basic knowledge to RAID.. if you want more info on RAID, head to wikipedia and google is also there to help you.

RAID 0:

In this configuration, two hard disks are used. Here, data is split and written on both harddisks simultaneously. i.e., for example, take a file, if it is split up into 4 parts A,B,C and D, A and C go on one hard disk and B and D go in other hard disk. As data is written paralley, great speed is achieved. If it is to be stored on a normal hard disk(written in serial fashion), the data takes 4 seconds to record( assuming that each part takes one second to be written[though its fairly a too large time]). But in RAID 0 configuration of two disks, it takes only 2 seconds.. wow, how fast!. The advantages are fast and inexpensive. But the disadvantages are its not reliable.. because, if one hard disk fails, then total data is useless and lost. RAID 0 is illustrated below.



RAID 1:

Here, same as RAID 0, two hard disks are used. But instead of splitting and recording the data, the same data is written twice in the two hard disks i.e., one hard disk is exact duplicate of the original one. This provides redundancy, i.e., when one hard disk fails, no data is lost and thus data saftey is provided. The advantages here is mainly redundancy.. it is safe i.e, you wont loose your data till atleat one of the hard disk is alive and runnig up fine. The main disadvantage is the very slow writing speed coz, the data is written two times,and also cost of the drive matters. The below pic gives a clear view of RAID 1 config

Playing with PIXels

Playing with images has fascinated everyone from professional photographers to a noob.
Now I will share some of the stuff I know in creating a photographic mosaic images using software called Andrea Mosaic (thanks to the developer)

Features of Andrea Mosaic:
1. Flexible options
2. Great UI
3. Ease of use
4. Its free

Download it from here.

Now I will explain you to create a basic photographic mosaic in few easy steps…

Step 1:
Download and install the software from the above link provided.

Step 2:
Open Andrea Mosaic and the application window.
Every option is self explanatory when you move your cursor over it and wait like shown below.

Now pass your cursor on to everything to view detail of each of the options.

Step 3:
Time for some fun!!!
Now you have to select the tiles (small images used to make the big one) Click the “select tile” option button and it opens a tile select window, in that click the add folder window and select the folder containing images for your tiles...

And then,

And now add the folder containing the images(the smaller ones to incorporate into the bigger one).

Step 4:
Save the tile by clicking the “save archive” button, now your tile will be saved by default name or any name you choose. Saving the archive is similar to saving a playlist for media players.

Step 5:
Now add the original image to be processed by clicking the “+” symbol button at the top of the window space. After adding, the image appears in the workspace provided with some grid lines as shown below…

Step 6:
You are almost done!!
Now, you can customize the image appearance..
Set Size parameters and tile duplication options (options are self explanatory when cursor is moved over).
Here “tile size” determines how many tiles to fit in to the image... Don’t worry if you have less amount of tile images, you can select the duplicate option to duplicate and fit the tiles to the size which you specify.
Under “color change” option, you can set the percentage of the color to which the tile should change with respect to the image to be processed (i.e.), The more percentage you set, the more the tiles are converted to the color of the image to be processed, The less percentage you set, the more the originality of the tile is kept.
The tradeoff between low and high percentage is the tile clarity and the final image mosaic clarity respectively.
The tile variants option lets you modify the alignment and orientation of the tiles within the image to be processed.
Finally, the “mosaic information” lists the information and customization of the work ready to be processed.

Step 7:
Now click the “more options” button to open the extra options to adjust image quality, output file format, save locations, setting borders etcetera. You can modify any setting or simply leave it to the default setting.

Step 8:
Now click the create mosaic option and wait….
Blimey!!!!! The image is ready…

This image is set with A4 mosaic size with 10000 tiles and a color change of 70%

Note: 1. To process a image with the same tile, create at least 30 duplicates of the tile in a folder and save it as an archive.
2. Use only JPEG images

Comments are welcome....

[Credits to the developer of the software]