When is a SAN not a SAN?


When is a SAN not a SAN?
Rick Cook

In the world of Windows 2000, "SAN" means both "Storage Area Network" and "System Area Network." In spite of the similarity of the names, and the fact that they are often both referred to as SANs in Microsoft-land, they are quite different things.

The System Area Network enables very fast communication between servers running Microsoft's Windows 2000 Datacenter by using Windows Sockets Direct Path (WSDP) over a special 1 Gbps fibre-channel-based channels. A Windows 2000 System Area Network isn't concerned with storage at all and only links Datacenter Servers connected to a shared device running Microsoft Cluster Server.

A System Area Network eliminates the overhead associated with TCP/IP in connecting two servers. Applications based on Microsoft's Winsock can also use the network to connect from one Datacenter server to another.

Further confusion can occur because the physical layer of the System Area Network uses special System Area Network adapters which perform roughly the same role a Host Bus Adapter does in a Storage Area Network. However SAN HBAs and SAN adapters are not compatible.

Microsoft provides a description of System Area Networks and how they work in article Q260176 in the Microsoft Knowledge Base, available at

Requires Free Membership to View

Microsoft's web site.

Rick Cook has been writing about mass storage since the days when the term meant an 80K floppy disk. The computers he learned on used ferrite cores and magnetic drums. For the last twenty years he has been a freelance writer specializing in storage and other computer issues.

This was first published in April 2002

There are Comments. Add yours.

TIP: Want to include a code block in your comment? Use <pre> or <code> tags around the desired text. Ex: <code>insert code</code>

REGISTER or login:

Forgot Password?
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy
Sort by: OldestNewest

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to:

Disclaimer: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.