Microsoft took a big step back so Vista could take a big step forward. New storage features in the forthcoming Vista operating system reflect Microsoft's realization that its Windows operating system lagged competing platforms in storage management features. The new Vista sports an improved file system, native support for hybrid disk drives (H-HDD), volume shrinking, enhanced I/O prioritization and drive encryption features.

Storage I/O's lead analyst, Greg Schulz, sees these features as Microsoft finally owning up to the reality that storage management is no longer a peripheral to the Windows operating system but is needed as part of its core ecosystem. Schulz cites Vista's new transactional file system as evidence that Microsoft is finally getting serious about storage. "A journaling file system makes Vista more than just a platform to run games on," says Schulz.

File system improvements

Vista's Transactional NTFS, like Longhorn's transacted file system (TxF), allows users to preserve data integrity during unexpected error conditions. For example, if a computer fails while an application is saving information to disk, the data may be corrupted since the save operation is only partially completed. To prevent this from occurring, TxF opens the file in transacted mode, saves the file and then commits the transaction. If the system fails during the save operation, it restores the file to its pre-save condition which prevents file corruption.

The Vista file system also includes major revisions to support the SMB (Server Message Block) 2.0 protocol. One major pain point that SMB 2.0 addresses, is the chattiness of the SMB 1.0 protocol, according to Navjot Virk, a Microsoft Software Design Engineer. "SMB 2.0 supports an arbitrary, extensible way of compounding operations to reduce round trips making it less chatty than SMB 1.0", says Virk.

Vista manages file handles, as well. SMB 2.0 increases the number of concurrent open file handles that a server can support and the number of shares that a server can share out. SMB 2.0 also provides more durable file handles which prevents clients from loosing connectivity to servers if short network glitches occur.

Which protocol, SMB 1.0 or 2.0, is used is decided during the negotiation phase between the client and server when the client advertises to the server that it can understand the new SMB 2.0 protocol. "If the server understands the new SMB 2.0 protocol, it is selected, otherwise it falls back to SMB 1.0, preserving Vista's compatibility with down level machines though they loose the benefits of SMB 2.0," Virk says.

Hybrid drives speed I/O, save batteries

Another storage feature that Vista adds is its native support of H-HDDs, which will provide users short- and long-term benefits. Using flash cache and traditional platter space in their construction, Vista recognizes a hybrid drive by sending an ATA command to the H-HDD that lets Vista know whether or not it is an H-HDD.

Mobile users will see some immediate benefit using this feature. "An initial benefit that mobile users will realize is a performance boost as H-HDDs allow some random I/O to be serviced by flash rather than the spinning HDD platter, which can be up to 10 times faster for small pieces of data", say Matt Ayers, program manager on the Windows client team.

Microsoft also expects that H-HDDs will extend the lives of batteries and disk drive. Known as Windows ReadyDrive, H-HDDs cache disk reads and writes without needing to spin the disk drive. According to Hiroshi Sakakibara, product manager on the Windows client team, this saves battery power on the machine and can also prevent disk failures when using laptops while on the go. "Windows ReadyDrive makes your laptop more rugged since it is less likely the disk will be spinning and susceptible to damage as one is running from meeting to meeting", say Sakakibara.

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."