What are the differences between SAN, NAS and DAS?

SAN(Storage Area Network);
SAN is used for applications to access BLOCK storage over an optical FC network using the SCSI protocol. (e.g. FibreChannel, iSCSI, FoE)

NAS(Network Attached System);
NAS is used for access to FILE storage over TCP/IP on an Ethernet network using either the CIFS (for Windows) or NFS (for Unix) protocol. (e.g. NFS, CIFS, AFS)

DAS(Direct Attached Storage);
DAS is a block device from a disk which is physically [directly] attached to the host machine. (e.g. IDE, SCSI, SATA)

Source: 
http://searchstorage.techtarget.com/tip/SAN-vs-NAS-Which-do-you-need
http://serverfault.com/questions/81723/what-is-the-difference-between-san-nas-and-das

How to play classical Atari 2600 games on PC?

Everyone misses Atari games of childhood but we are able to play them on our new PCs now.

At first, we need to install Atari emulator on PC which will be Stella. To download it, please click below link. http://stella.sourceforge.net/downloads.php

Subsequently, we should download ROMs of our desired games. To download them, please click one of these links. 

• http://www.atariage.com/system_items.html?SystemID=2600&ItemTypeID=ROM
• http://www.atarimania.com/rom_collection_archive_atari_2600_roms.html

Finally, we are ready to play. 

• Run Stella
• Select your favorite ROM (.bin)
• Enjoy! :)