RAID

RAID 

                          Redundant Array of Independent Disks is a redundant system uses multiple Hard Drive to store your data,so if one drive is fail your data is safe and accessible.

Mirroring – Multiple disk containing identical data

Striping - sequential blocks of data are split among multiple disk

Fault-tolerant – This is where parity data is stored allowing data to be recovered if a problem is detected

RAID 0

                      This configuration is the fastest of all the RAID levels, it uses a technique called data striping (see below) and requires at least 2 hard disks.

RAID 1

           This level uses a pair of hard disks at a time to provide fault tolerance (there is no performance benefit) and requires at least 2 hard disks.

Using a technique called disk mirroring (see below) the same data is written to both disks at a time, so if one hard disk crashes then the same data is available from the remaining hard disk. 

RAID 5

                 Data is striped across the drives in bytes, the parity data for one particular drive is stored on another drive allowing the data to be rebuilt using the parity technique.In the event of a disk failure, the data from the failed disk is reconstructed from parity striped across the remaining disks.

Minimum number of drives required: 3

Usable capacity will be generally be the physical capacity less one drive.

So if u have 4 1TB drives there only 3 TB of usable capacity

 

RAID 6 (double parity)

                RAID 6 is similar to RAID 5 in terms of striping and parity, with the major difference being that RAID 6 can tolerate two disk drives failing.

Minimum number of drives required: 4

Usable capacity will be generally be the physical capacity less two drive.

So if u have 4 1TB drives there only 2 TB of usable capacity

RAID 10

               Initially a pair of drives is mirrored as in RAID 1 and further striped as in RAID 0. Raid 10 is also known as RAID 1+0 .

Minimum number of drives required: 4

Usable capacity will be generally be the physical capacity less two drive.

So if u have 4 1TB drives there only 2 TB of usable capacity

The Growth of Android 

Nokia Lumia

Nokia Lumia 520

Main Features: 

4-inch IPS LCD Display |

Windows 8 OS |

1GHz Dual-Core processor,

512MB RAM |

5MP Rear Camera |

8GB Internal memory,

expandable up to 64GB |

3G, GPS, GLONASS, WiFi, WiFi Hotspot, Bluetooth, USB

1430 mAh battery

 

Design

It comes with flashy colours such as yellow, blue, red along with the usual black and white. You can changethe rear casing as per your choice.

 

Display

Lumia came with  4-inch IPS LCD with an 480x800 pixel resolution.The screen is so sensitive that you can operate with your finger nails.

 

Processor & RAM

It served with 1GHz Dual-Core Snapdragon S4 processor with adreno 305 GPU.it seems that 512 MB of RAM is not enough,however it quiet did the job,Asphalt 5 played very well with a noticeably warm.

 Camera

It comes with a 5 MP camera and 720p video record,without flash camera clicks are too sharp.but the video quality is good for this range

 Memory

It comes with 8 GB internal and a whopping 64 GB expandable via microSD card.And i learned from other blog is that nokia is offering 7 GB free cloud space. WOW!



verdict

Nokia Lumia 520 is a decent smartphone,packs with lots of free windows stuffs,like free office plus Nokia Music for free music and Nokia's Here location apps.With all these features and if you a are NOKIA enthusiast this smartphone is so far the best budget phone.

TITAN Supercomputer

TITAN crowned as World's Fastest Supercomputer

Titan Cray XK7 is the latest supercomputer to be deployed at  Oak Ridge National Laboratory 

                                       The hardware comes from Cray.Titan uses 200 cabinets which has 18,688 nodes (4 nodes per blade, 24 blades per cabinet) each containing a 16-core AMD Opteron 6274 CPU with 32 GB of DDR3 ECC memory and an Nvidia Tesla K20X GPU with 6 GB GDDR5 ECC memory.The total computational power of Titan is 17.59 petaflops per second(17 thousand trillion calculations per second).There are a total of 299,008 processor cores and just over 710 TB of RAM.

The initial cost of the upgrade was US$60 million

Storage

 
               System storage is equally impressive: there's a total of 10 petabytes of storage in Titan.ORNL uses 10,000 standard 1TB 7200 RPM 2.5" hard drives. The IO subsystem is capable of pushing around 240GB/s of data






OS & Software




Titan runs the Cray Linux Environment, which is based on SUSE 11.



 
Power Delivery

Total power consumption for Titan should be around 9 megawatts under full load and around 7 megawatts during typical use.

ILO

 ILO virtual commands

 The options to restart a server using the ILO are contained under the virtual power tab.You can do one of four options:

    Momentary press – this is like pressing the power button on your laptop/pc or server, with Windows 2000 and above (if I remember correctly), it should cleanly shut down the operating system

    Press and hold – this is like pressing and holding the power button, it will turn off the computer completely and will not cleanly shut down the server

    Cold boot of the system – this effectively powers off the server and restarts it.

    Reset system – this is the ILO way of rebooting it without cleanly restarting the operating system, if your server has hung and wont respond, this might be the option you select.