Windows Driver Kit (WDK) Documentation Blog : WinHEC 2008

Storage Devices at WinHEC 2008

wdkblog — Thu, 27 Nov 2008 08:40:00 GMT

Quite honestly, spending most of my time deep in the innards of the kernel file system stack, I wasn't entirely convinced that WinHEC would have a lot of relevant information to offer - boy, was I wrong!

As a matter of fact, WinHEC provided so much info that, for the sake of brevity, I am "forced" to focus on just one aspect that I found particularly interesting: storage devices.

From the WinHEC presentations I attended, "serious" storage devices essentially come in three flavors:

· Solid state disks (SSDs)

· Traditional hard drives or hard disk drives (HDDs)

· Hybrid drives (SSD + HDD)

And each flavor has its pros and cons:

Solid State Disks (SSDs)

Probably the SSD that most folks are familiar with is your garden variety flash thumb drive. You pop it into a USB port and voilà, you have a new "disk drive". Well, let's just say that there are prototype SSDs that make a thumb drive look like a lethargic gnat. The prototype I saw, implemented on a PCIe card, was very performant. However, despite their performance, every silver lining has a cloud:

Pro	Con
Speed: Prototype SSDs have impressive IOPS (I/O operations per second), particularly for reads. The PCIe prototype I saw spent much of its time waiting for the rest of the system to respond.	Endurance: Currently, SSD NAND flash chips tend to wear out with use. In general, you need to erase NANDs before writing to them (write-in-place is not an option as it is for rotating drives) - you're good for about 100,000 erases for SLC (single-level cell) flash and about 10,000 erases for MLC (multiple-level flash). Ultimately, as the number of erases goes up, so does the number of device errors, which is why wear-leveling (typically implemented in the firmware of the device) is critical for SSDs. (Wear-leveling attempts to evenly spread the erases around on the device, increasing device endurance.)
$/IOPS: For a typical consumer, dollars per I/O per second ($/IOPS) really isn't that important - low $/GB is what's critical. However, for performant environments, $/IOPS can trump $/GB.	$/GB: SDDs currently have a relatively high dollar per GB value as compared to HDDs.

Interesting Tidbits

· In order to make intelligent wear-leveling and NAND block cleaning decisions, file type metadata can be important. For example, photos, music, and videos tend to be "cold" read-only-ish data. Knowing what's "cold" and what's not could be very important in choosing which blocks to write data to, from a wear-leveling perspective.

· SSDs can function as either slow memory or a fast "disk" - they've created a new tier in the system. Likewise, both memory teams and/or traditional disk teams at various companies can develop SSDs.

· SSDs are starting to encroach in the optical media space - flash is now large and cheap enough to do so.

· Typically, if you want more performance from a computer, you buy more memory and a bigger hard drive. One study showed that you can get the same amount of performance with a smaller amount of memory plus an SSD (for search, database, and similar applications). So for applicable applications, an SSD can reduce operating costs (despite their endurance issues).

· Currently, there are not international metrics for SSDs. For example, how do I choose a device with high endurance? What is the current "health" of my installed SSD device? Ratings for important SSD attributes need to be hammered out.

· Can Windows boot time and file system indexing be increased via an SSD? MS is working on these questions now.

Hard Disk Drives (HDDs)

HDDs are, of course, your traditional rotating magnetized-disk-o-metal with a swing arm and various other mechanical components. Despite their "old school" nature, HDDs are undoutably not going away anytime soon. Historically, there have been many contenders but HDDs have always survived and excelled. Generally, it's $/GB that drives storage device sales, and given today's widespread use of digital cameras and camcorders, the need for cheap storage is only going to grow. One study predicts that 2011's storage needs will be about 10 times that of 2006's.

Pro	Con
$/GB: So far, HDDs provide the biggest bang for the bug with respect to this metric.	$/IOPS: Compared to SSDs, HDDs have relatively high $/IOPS.
Endurance: Compared to current SDDs, HDDs have outstanding endurance characteristics.	Slow: Compared to SSDs, HDDs can seem downright sluggish (particularly against SSD read operations).
Extensible: HDDs can easily be clustered, placed in RAID arrays, etc.

Interesting Tidbits

· One WinHEC presenter felt that SSDs currently don't have sufficient capacity - they'll need about 10x their current capacity to compete with HDDs.

Hybrids (SSD + HDD)

Hybrid drives have been around awhile in the sense of "small" memory caches on HDDs to help speed up access to frequently accessed data. The hybrid device, as described at WinHEC, is much more than this - it would contain a significant SSD component as well as a hefty HDD component.

To me, hybrid drives really offer the best of both worlds. For example, the hybrid firmware could keep an eye on the health of the SSD component (i.e., notices when NAND chips are starting to fail) and could guarantee reliability by shunting data to the HDD component as appropriate (at the expensive of device IOPS, of course). One presenter's contention was that successful storage device manufactures will need to provide all three flavors classes: SSD, HDD, and hybrid.

Call to Action

If you've ever attended WinHEC, I'm sure you noticed the myriad call-to-action slides at the end of nearly every presentation. Yes, these can be a tad annoying but there's one I would like to pass along which affects file system driver developers. Per the Clustered Shared Volumes folks, please test your file system drivers with the CSVFilter.sys minifilter in the stack (i.e., any data transformation drivers found below CSVFilter.sys will result in all I/O to remote volumes being done over SMB, with CSV Direct I/O not being used for that particular CSV volume - this can significantly impact performance).

Finito

Well, that about wraps things up for me - granted, it's the 10,000 foot WinHEC overview of storage devices (at least my interpretations thereof). If you'd like less than a 10K' overview, definitely check out WinHEC's 2008 Conference Presentations - there's a lot of stuff here - the relevant presentations for this article were as follows:

1. Design Tradeoffs for Solid-State Disk Performance

2. Solid-State Storage in Server and Data Center Environments (should be available soon)

3. New Developments in the Storage Platform

4. Windows 7 Enhancements for Solid-State Drives

5. Is Your Disk Drive Going Away

6. Enhanced Storage Support in Windows 7

7. Windows Virtualization and Clustered Shared Volumes

Hope you've had a bit of fun from this post, take care!

- Karlito Bonnevie [MSFT], Programming Technical Writer, Installable File System Documentation

Final thoughts from WinHEC

wdkblog — Fri, 07 Nov 2008 18:43:00 GMT

The WinHEC conference is wrapping up this afternoon. The conference has been a well-oiled machine, a tribute to our colleagues that run the event. A few trends that I've observed this week:

Power management is on everyone's mind. Consumers are willing to pay more for a laptop that has great battery life, so there's plenty of incentive to produce machines that are hyper efficient. Windows 7 will include new tools for improving battery efficiency (if you have the M3 build, try typing powercfg /energy from the command line), and several sessions focused on using the Windows Performance tool kits to lessen the load on the CPU. Windows 7 will also be more aggressive in shutting down LCD panels during periods of inactivity.
Solid state drives are all the rage -- and with good reason. They're incredibly fast, growing in capacity, and offer many advantages over conventional hard disk design.
Multi-touch apps are coming to a Windows 7 machine near you, and it's something to be excited about. The API layer in Windows 7 will make it easy to build touch based applications. The HP Touch Smart machines are a great indicator of what's to come in this space.
Device Staging is one of the single biggest innovations in Windows 7, and adding support for Device Staging is a relatively easy task for hardware vendors. Device Staging packages use a well defined and simple XML schema to describe the tasks a device can accomplish (i.e., "Play Media File", "Import Pictures", "Scan an Image", etc.), and the UI offers an opportunity to provide a highly differentiated user experience for your device.

I'll be part of a panel discussion on the Windows Driver Kit (WDK) for Windows 7 this afternoon -- if you're at the conference and are interested in learning more about our documentation priorities for Windows 7 Beta I invite you to come join us (the session is in room 403/A). Among other things, I'll discuss:

Our documentation priorities and strategy for Windows 7 Beta.
How we handle customer feedback on the documentation.
The results of our recent documentation survey.
Our plans for machine translation of our content.

Of course, I'll be happy to answer questions from community members as well.

Keith Boyd, Sr. Content Publishing Manager [MSFT]

WinHEC -- Day 2 Keynote with Bill Laing

wdkblog — Thu, 06 Nov 2008 21:50:00 GMT

Bill Laing just completed his day two keynote presentation, focusing on key technology updates and improvements coming in Windows Server 2008 R2. Not suprisingly, there was a strong emphasis on Hyper-V (Bill was presented his own "can" of Hyper-V near the end of the presentation... He indicated that he preferred water). The most impressive demo involved streaming a media file from a virtual machine, while simultaneously moving a 3GB file to a share on that virtual machine and changing the node of the machine in real time. There was no perceptible loss of quality in the video while these operations were running simultaneously -- an impressive feat, and one that drew a loud cheer from the crowd. Immediately the machine was moved back to the original node, again with no loss of quality in the video, and not causing any problems for the large file that was still copying.

SQL Server code-name "Kilimanjaro" was also demonstrated, with an emphasis on expanded support for logical processing units. Currently, SQL supports up to 64 logical processors -- Kilimanjaro will support up to 256 logical processors. A compelling demo of this functionality showed high end servers from HP and IBM running SQL on 256 logical processors at once, all with balanced load. It was quite a site to see all 256 processors appearing in the Task Manager. The Kilimanjaro release is scheduled to ship around the same time as Server 2008 R2.

Bill demonstrated one of the ways that Windows 7 clients will "light-up" when working with Windows Server 2008. A new technology called "branch caching" enables remote work sites (i.e. satellite offices), esp. those operating in low bandwidth conditions to speed up network operations by caching files on local machines in the satellite office. Files are subsequently served from machines on the the local network rather than going out over the wire to the main office. The demo of this technology was impressive -- a 1.5 mb file that otherwise took 20 seconds to download over a 512kb DSL line downloaded and opened instantly in the branch cache scenario, since the file was served up by another client that already had a copy of the file. You can read more about the BranchCache in the Developer Guide for Windows 7, here: http://code.msdn.microsoft.com/Win7DeveloperGuide.

Bill's speech has already been posted to the WinHEC site, and can be viewed here: http://www.microsoft.com/whdc/winhec/default.mspx.

For more information on the forthcoming R2 release of Windows Server, visit http://www.microsoft.com/windowsserver2008/en/us/default.aspx.

Keith Boyd, Sr. Content Publishing Manager [MSFT]

Update from the WinHEC Conference Floor

wdkblog — Wed, 05 Nov 2008 21:31:00 GMT

Steven Sinofsky and Jon DeVaan just wrapped up their keynote presentation. There were some impressive demos showing off the new Device Experience Platform. Judging by crowd reaction to the demos, device staging will be one of the most exciting new features in Windows 7.

Aptly, Jon focused his attention on the fundamentals of Windows (side note, if you haven't been following the E7 Windows engineering blog, you should. You can find it at http://blogs.msdn.com/e7). Live demos showed that boot time for Windows 7 has been improved significantly over Vista (this is due in part to system services and drivers being loaded in parallel in Windows 7, vs. serially in Windows Vista and earlier). Shut down time was quicker, with new tools helping to diagnose and fix services that prevent smooth system shut down. Power management is better in Windows 7 too -- the xPerf performance toolkit already available on WHDC (http://www.microsoft.com/whdc/system/sysperf/perftools.mspx ) was used to help troubleshoot and demonstrate improvements in efficiency.

Steven demonstrated opportunities that Windows 7 enables to differentiate the user experience, focusing on the new Device eXperience Platform (DXP), new form factors and PC designs, and new interaction models (sensors and multi touch). The live demos of DXP using pre-release M3 bits garnered enthusiastic reactions from the crowd. I'm convinced this will be one of the most exciting features in Windows 7, and will have a significant positive effect on customers and the PC eco-system.

As noted in an earlier blog post, you can read more about new features for developers in the Windows 7 Developer Guide, located at http://code.msdn.microsoft.com/Win7DeveloperGuide.

Update: You can now view Steven and Jon's keynote speech online at http://www.microsoft.com/whdc/winhec/default.mspx.

Keith Boyd, Sr. Content Publishing Manager [MSFT]

WDK Doc Team Invades WinHEC 2008

wdkblog — Sat, 01 Nov 2008 02:46:00 GMT

In case you are one of the lucky ones who will be going to WinHEC next week, be sure to look for people wearing these name badges:

Keith Boyd, our new WDK Senior Content Publishing Manager (the boss)
John Jackson, Senior Programming Writer (specialist in Virtual Machines and User Mode Display drivers)
Karlito Bonnevie, Programming Writer (specialist in File Systems)
John Osborne, Technical Editor (familiar with a wide range of technologies)

Yes, the WDK documentation team is sending four of our finest to Los Angeles for the week. If you see any of these four, be sure to tell them what you like and don't like about the WDK documentation. They've come all that way, just to listen to you!

In particular, Keith will be part of a panel discussion on "The Windows 7 Windows Driver Kit" on Friday, November 07, 2008, along with Jennifer Stepler and Craig Ziegler (WDK gurus). They will be telling you about all the exciting things that are coming in the new kit.

For those of you who can't attend, you can read Keith's daily blog reports from the convention floor.

What the heck is WinHEC?

WinHEC is the annual Microsoft Windows Hardware Engineering Conference and will be held this year in Los Angeles, November 4-7, 2008. For more information about the 140 technical sessions, panels, and chalk-talks at WinHEC, see http://www.microsoft.com/whdc/winhec/

— Seth McEvoy, [MSFT], WDK Doc Blogmaster