Diligent Technologies is rolling out virtual tape packages for mid-sized companies, having previously focused on the enterprise.

The company has launched the ProtecTIER Mid-range Entry Package and the Mid-range Standard Package, two hardware-software appliances that let customers perform disk-to-disk backup and de-duplication of redundant data.

While the appliances emulate tape libraries, they are faster and with the de-duplication of data can reduce the amount of data being backed up by as much as a 20:1 ratio. The appliances are also a first for the software vendor. Diligent has previously let users buy its ProtecTIER software and its HyperFactor inline de-duplication technology and run it on a server of their choice.

The two new appliances comprise a Linux operating system and host bus adapters (HBAs), bundled with as much as 20TB of Serial ATA storage and the company's ProtecTIER software.

The Mid-range Entry Package includes a server with dual-core processors and two dual-port HBAs. It supports 12 tape drives, 16,000 tape cartridges, two virtual tape libraries (VTL) and as much as 10TB of Serial ATA disk. The Mid-range Standard Package also includes a dual-core server, dual-ported HBAs. It can scale to 20TB of storage capacity and 16 tape drives, 16,000 cartridges and four VTLs.

In contrast, Diligent's Enterprise Virtual Tape Library supports as much as 30TB of disk, 256 drives and 15 VTLs.

The company estimates the size of the mid-range market at 20,000 accounts. Those customers consist of companies that are backing up less than 4TB of data each day and have one or two dedicated staff for backup operations.

IDC estimates that the VTL market will grow quickly. "We expect VTL market value will double over the next five years," says Robert Amatruda, research director at IDC. The VTL market is expected to reach $1.4 billion by 2011, while the number of terabytes being backed up will increase at a 47.4 percent compounded annual growth rate.