Disс emulator is an application that makes virtual images available for use and recognizable by the operating system.
Disс emulation is a creation of virtual CD/DVD/HDD device that imitates the real one.
Disс image is a file that consists of the whole data from some physical disc and information about its structure, and so can replace the real optical disc. To use an image, you need a special software -- emulator like DAEMON Tools.
iSCSI is Internet Small Computer System Interface that allows using remote devices shared by the network.
iSCSI Target is a virtual or physical device that is located on ISCSI Server, but can be access via iSCSI protocol.
iSCSI Server is a remote storage that gives clients an access to the certain virtual or physical devices.
iSCSI Initiator is a computer that connects to iSCSI Server remotely and can use its targets (devices) just like the local ones.
Mounting is a process of making virtual images available for use. This operation is similar to the insertion of the optical disc to the physical drive.
Unmounting is a process of removing virtual devices from the operating system. This operation is similar to the ejection of the optical disc from the physical drive.
Virtual drive is a device that appears to the operating system like a real physical drive.
.mdx / .mdf is an image format that is developed by the DAEMON Tools team.
*.dmg is an image format that is developed especially for Mac OS.