ATTO Technology VT-Class manual Appendix B ATA Disk Technology, Feature, Fibre Channel

Appendix B ATA Disk Technology

ATA is the dominant disk drive technology today and will be for the foreseeable future. It offers all the cost advantages of a mass produced, consumer-driven technology which is rapidly being driven forward. Today ATA also offers all the performance and reliability features needed to create high performance ATA-based disk storage arrays.

We view ATA as the perfect disk drive technology for “in-the-box” disk storage array solutions.

Aggregated Data Interface Technology (ADXT™) with its built-in Virtual Device Manager (VDM), Data Routing Fabric (DRF) and ATA Interface Engines (AIE) smoothly and efficiently organizes Fibre Channel data streams for storage or retrieval on ATA disk drives. ADXT provides end users with the power and sophisticated data control needed to take moderately priced ATA disk drives combine them in a disk storage array and power them to the performance levels of SCSI or Fibre Channel disk arrays

Unlike other storage arrays which use expensive SCSI or Fibre Channel disk drives to achieve performance, the Diamond Series uses lower cost ATA disk drives combined with an intelligent midplane to create a storage array with exceptional price and performance characteristics.

Disk features and standards

ATA disk drives are used in the enormous PC marketplace and an estimated 85% of all disk drives sold today contain an ATA interface. Shipments of ATA drives are expected to grow rapidly over the next five years with increasing consumer and business demand. In general, ATA disk drives are the “driver” of all disk storage technology as the costs, volumes and demands of the PC marketplace are the primary focus of the world’s largest disk drive manufacturers.

ATA disk drives today offer capacities comparable to SCSI and FC disk drives – although at a tremendously lower cost. Advances in platter and head technology will push drive capacity along a very steep curve in the next five years. The chart below summarizes ATA and other disk interface standards. It clearly indicates that ATA drive technology offers characteristics that ideally suit it for “in the box” usage in high capacity, high performance disk arrays.

	Feature	IDE	ATA	SCSI	Fibre Channel
Connectivity
•	Max Devices	2	2	16	126...millions
•	Cable Length	46 cm	46 cm	25 m	10 km
Performance
•	Bandwidth	16 MB/sec.	100 MB/sec.	160 MB/sec.	200 MB/sec.
•	Bandwidth/drive	8 MB/sec.	33 MB/sec.	10 MB/sec.	1.6 MB/sec.
•	Multi-threaded I/O	No	Yes	Yes	Yes
Max Initiators		1	1	<16	125...millions
Topology		Bussed	Bussed	Bussed	Loop/Fabric
Error Detection		None	Yes	Yes	Yes
Protocol “weight”		very light	light	medium to heavy	heavy
•	Cost
•	Interface	n/a	lowest	medium to high	highest
•	Drives	n/a	lowest	medium to high	medium to high
Manageability		none	low to medium	medium	medium+

A-iii

ATTO Technology Inc. Diamond Storage Array Installation and Operation Manual