Examples of these super-low priced NAS boxes include Quantum's Snap Server 2200, a dual-drive 160GB model priced at $.97/MB; Dell's 480GB 715N at $.93/MB; and Hewlett-Packard's (formerly Compaq's) NAS S1000 at $.85/MB.

One of the latest entrants into the low-cost NAS market is IBM, which recently added the TotalStorage NAS 100 to its line-up. It previously consisted of the SCSI-based NAS 200 and Fibre Channel (FC)-based NAS 300G. Equipped with 480GB, the NAS 100 comes in at a competitive $.92/MB.

As a general rule, the greater the capacity of the disk drives inside the box, the lower the cost-per-megabyte. 160GB disk drives are currently shipping, and 240GB drives are on the horizon.

In contrast, SCSI-based NAS pricing in 2001 hovered around $.10/MB, estimates Pushan Rinnen, a senior analyst at Gartner. Meanwhile, vendors are closing the gap between low-end and midrange NAS by adding more and more advanced features.

For example, IBM touts the NAS 100's hot-swap drives and dual 10/100/1000 Ethernet ports. That's important, because sometimes, "there's very little - if any - IT skill at the locations where we're putting this product," says David Vaughn, IBM product manager for storage networking. Consequently, IBM focused on availability and reliability features, as well as installability.

Other carrots used by NAS vendors to lure in customers include the ability to rackmount SCSI ports for attaching a local tape drive and software such as snapshot and replication - features that are commonplace in higher-end systems from the likes of Network Appliance and EMC.

Of course, NAS devices based on ATA will always lag behind their SCSI and FC counterparts because of ATA's scalability and performance limitations, but in terms of reliability, Rinnen says, "ATA is pretty much on par with SCSI."