Each system offers as a standard, dual 4.7Gb DVD-RAM drives. Single archive drive systems are available at customer requests. Dual drive systems can be configured to record in sequential mode or parallel. In sequential mode one drive will record while the other is in standby. With dual drive systems, either drive can be designated as a primary drive. In parallel mode both drives record identical copies for redundancy. The drives may also be configured to operate in a play/record manner, one drive record, one drive play, etc.