Quantum has added its proprietary DLT-S4 format to an ADIC Scalar library as part of its continuing product integration work following last year's acquisition of the company.

The DLT-S4 format offers 800GB raw capacity with a data transfer rate of 60MB/sec. It is matched by the LTO Consortium's open LTO-4 format, offering an equal 800GB raw capacity but a faster 120MB/sec transfer rate.

Quantum has added the DLT-S4 format to all of its PX library range from the high-end PX720 enterprise library with up to 3,616 slots to the entry-level PX502 with up to 38 LTO slots or 31 DLT slots. The ADIC Scalar libraries exceed the PX line, with its range-topping Scalar i10K - up to 13,884 slots - through the i2000 - up to 3,492 slots - to the Scalar 24 with 24 LTO slots or 21 DLT ones.

The DLT-S4 format has been added to the i2000 and will be added to the i500 this summer, leaving the i10K as the only DLT holdout - it does not support any DLT format. Presumably DLT-S4 support will be added to the rest of the Scalar line over time. The Scalar 100 and 24 products already support DLT 600 and 320 formats so adding DLT-S4 support to them should be a snip. No date has been provided by Quantum for adding DLT-S4 to the Scalar i10K library.

Existing Scalar i2000, 100 and 24 customers already using the DLT format now, in theory, have an upgrade path to DLT-S4. The addition of DLT-S4 support to the Scalar i2000 and 500 libraries doesn't affect PX library customers unless they want to add these libraries to their existing DLT-S4-supporting PX libraries. They will be able to do this without having to change tape format.

The long-term likelihood for Quantum is to have a single line of tape libraries. This may be achieved by migrating Scalar users to PX, vice versa, or by introducing a new library product range combining Scalar and PX features.

None of the PX or the Scalar libraries yet support the LTO-4 format. It must be a given that, as Quantum is in the LTO Consortium, it will provide LTO-4 support in its library range. LTO is growing its overall market share in the tape backup market whereas DLT is not.