The Back Plane is that part of a storage system which lies immediately behind the read/write devices themselves. It might be within the same physical box as the devices, or a separate framework into which disk or tape drives are plugged.

Back Planes define at a very fundamental level the performance of the system- the rate at which they can push data around, and the size of storage media objects (disks or tapes) that the system can use.

Fibre Channel (g) connection based systems have been around for several years time. They are quite expensive, but offer an enormously fast throughput of data. Costs are about as low as is possible with this technology.

ATA(g) is the disk drive connection standard common to many PCs. It is a relatively low cost system, and as its performance has been improved, it has been introduced to larger and larger storage devices. Most recently, the standard has been enhanced as Serial ATA, or SATA(g), in which form it offers very respectable performance for a reasonable cost.

SCSI(g) as a standard for managing storage devices is a very well established. The system has been steadily developed though, and in it's latest incarnation- iSCSI(g)- is amongst the best available for managing large data stores.

Migrating between disk or tape drive types will often involve a change in Back Plane type as well, particularly if the move is from high volume, low cost with redundancy to higher cost, greater reliability, or vice versa.