A DiskeeperBlog reader recently had this question, and I felt it deserved it's own thread: "Does NCQ (Native Command Queuing) on the newer SATA drives help in reducing fragmentation, or the impact of fragmentation on HDD performance? I have run across this subject recently on a few sites, and I'm thoroughly confused about what NCQ does to fragmentation." - Durian --- A very good question and, I agree, a very complicated one. As it turns out, I'm in the midst of a very long white page paper on various data storage technologies and how they relate to fragmentation. In it is a semi-completed "chapter" on SATA, SCSI, FC (Fibre Channel), and SAS (Serial Attached SCSI) disks. I've taken a small excerpt from that section to address your immediate question. I apologize in advance if it reads poorly as it still needs some polish. I recommend chapter 1 of the "Shortcut Guide to Managing Disk Fragmentation" by Microsoft Product Manager Mike Danseglio, for technical references. Wikipedia can help define some of the technologies described if you need more info.

The Lets Talk Computers radio show aired 2 interviews with Anthony Crea. Anthony is our Channel Manager. As part of his key responsibilities he's an expert on Diskeeper and Undelete. He travels (practically non-stop!) around North America training resellers and distributors on them. In part 1, Anthony Crea discussed many simple, but important ways that companies can increase the efficiency of their employees, by making the computers they use faster, easier and more enjoyable to work with. Part 2 continues the discussion. Listen to it here, or read the transcripts here (Part 1) and here (Part 2).

Windows IT Pro recently researched and published a new paper evaluating Diskeeper on the new Windows Vista operating system. You can view the paper (sponsored by Diskeeper Corporation) here. We are also wrapping up another study, done in-house by our Development Testers, evaluating the improvement to anti-malware scan times when using Diskeeper. Check out our Knowledge Center in a couple of weeks to read it.

For anyone interested (a few people have asked), we just completed the Windows Vista logo certification requirements. No major changes to the product except that you'll find, in builds 11.0.707 and higher, a couple of Diskeeper files that used to be placed in the systemroot folder moved to the standard Diskeeper folder in Program Files. To accomodate this new path, the Diskeeper installation creates a new entry in the Environmental Variables so the sytem can properly find these files.

"DO NOT DEFRAG DATABASES!" is one of the more popular myths/misconceptions we encounter in promoting and selling Diskeeper. BTW; when I define database (DB) servers, I also include purposed servers such as email, Domain Controller, DNS, etc. And of course MS SQL, Oracle, Sybase, and others (where the DB back-ends an app - e.g. a Customer Relationship Management program). I've seen technically comprehensive studies measuring IO throughput and transactions per second (TPS), performed by customers, validating the need for defragmentation of their database servers. They spend weeks/months of careful execution, verifying the source of performance issues and that defragmentation truly solves them. The degree of benefit that defragmentation brings to databases depends on several factors. The obvious of course is the degree of fragmentation. The less obvious include the purpose of that database and how it is used. Defragmentation is not going to solve all DB-optimization requirements, but it is a piece in the puzzle. Often a recommendation to "NOT defrag" hinges on the, understandably, accepted conception that defragmentation-generated I/O will impact the use of that DB. That is especially true when that database must operate at capacity 24/7. I agree with those caveats 100%. With free/built-in defragmenters, there is a use/benefit trade-off, and they can do more harm than good. That is where advanced defragmentation technology such as InvisiTasking comes in. If you are interested in more information on defragmentation and databases (i.e. does Diskeeper defragment the internal records?), there are white papers in our Knowledge Center (see link on the left), as well as product reviews by DBAs (Database Administrators). Here is a link to a recent review done by SQL-Server-Performance.Com.