A benefit that Storage I/O's Greg Schulz expects corporations to realize longer term is that application programmers will learn to capitalize on its performance capabilities by storing certain application data in the H-HDD's cache. Schulz observes, "AIX can already communicate with certain IBM lines of storage and tell them which data to keep in memory. I expect Windows applications to eventually take advantage of this feature as well."

Volume Shrink

Another new Windows Vista feature, Volume Shrink, is one that at least one user questions how much value it will provide. The shrink volume allows users to reduce the size of a disk volume so administrators may re-allocate the excess capacity for other purposes. David Stevens, a systems manager at Carnegie Mellon University in Pittsburgh and a Windows Vista beta tester, doubts he will have much use for it. "From a macro storage perspective, this feature makes SAN-attached storage more difficult to manage since it does not help me to identify which LUNs (logical unit numbers) to recover and I potentially loose track of which application is using which storage," Stevens says.

I/O prioritization

Vista's enhanced ability to prioritize I/O was one feature that did intrigue Storage I/O's Schulz. While Windows already supports I/O prioritization, the current implementation potentially introduces head-of-line blocking. Schulz analogizes, "This problem is akin to two [cars] going side by side down the Interstate at 40 mph. They have top priority but they slow everyone else down behind them."