Hybrid Hard Drives with Non-Volatile Flash and Longhorn

1. Hybrid Hard Drives with Non-Volatile Flash and Longhorn Jack Creasey Program ManagerHardware Innovation GroupMSHybrid@Microsoft.com Microsoft Corporation

2. Session Outline • Demo Introduction • Hybrid Hard Disk Architecture • Power Savings using NV Cache • Demo Results (Power saving) • Faster Boot and Resume Process • Demo (Boot and Resume) • System Design with the Hybrid Hard Disk • Other Design Approaches • Next Steps

3. Session Goals • Attendees should leave this session with the following: • An understanding of the power savings that can be achieved using Hybrid Hard Disk technology • An understanding of the boot and resume efficiencies that can be achieved using Hybrid Hard Disk with Windows codenamed “Longhorn” • An understanding of the increase in MTBF expected from a Hybrid Hard Disk • Knowledge of where to find resources to aid in system design using the Hybrid Hard Disk

4. Storage Devices: Key Windows Strategies Storage FabricsServer/Enterprise Leading platform supporting storage fabrics Optimized platform features enabling new customer scenarios in Personal Storage Personal StorageClient/Consumer Timely, comprehensive, quality platform support for optical devices Optical PlatformClient/Consumer Preferred Storage Platform Partner/Customer Preferred platform for developing, integrating, and deploying storage devices

5. Demo • Power Savings

6. Why Change the Disk Drive? • Consumes 10-15% of the power budget in mobile solutions • Slow power up • Spin up times can be 2-5 seconds • Seek and rotational latency is a performance bottleneck • Fragile, shock prone, low MTBF in mobile systems • Most common failure point in mobile solutions • Failure may result in user data loss

7. What is a Hybrid Disk Drive? NV Cache Add a non-volatile cache Dram Cache ATA Interface

8. Why is a Hybrid Hard Disk Better? • Reduce Power Consumption • Read and Write disk data while drive is in a low power state with the spindle stopped • Faster Boot and Resume • Instant access to data in NV Cache • Higher Reliability • Better shock resistance • Lower operating duty cycle

9. Hybrid Disk Drive Benefits Up to 90% Power Saving when powered down Read and Write instantly while spindle stopped Dram Cache ATA Interface NV Cache

10. Technical Assumptions for Hybrid Disk • Longhorn* with its advanced memory management is the optimal for caching read data (but not write data) • The Hybrid Hard Disk NV Cache is the optimal location for write data • NV Cache should be >= 64MB and we recommend 128MB • Longhorn* will be able to define data (LBAs) to be Pinned in the NV Cache for Boot and Resume benefits * Planned for Longhorn Beta 2

11. Flash Buffer Size for Power Reduction • Field data from Windows XP-based PCs • Preliminary results: • >9,000,000 10min “active use” intervals • 93% of 10min active use intervals < 64MB unique data written

12. Power Saving Mode Windows Longhorn DRAM ATA Controller Motherboard 64-128MB NV Cache Hard Disk Controller • Windows memory management buffers disk data in System DRAM which fulfills reads • Windows puts the HDD into NV Cache mode which spins-down the disk spindle and results in write (and read) IOs to the NV Cache • Upon NV cache miss or the NV Cache filling the spindle is spun-up to satisfy reads and flush write data to magnetic media • The disk spins-down and continues to use the NV Cache 2.5” HDD

13. Power Saving T 15 s • 80% reduction in power can be achieved (from 1.2W to 0.24W) • Assumptions • Pavg active = 1.2W (measured) • Pavg with Flash write buffer and “Longhorn” kernel = 0.18W (calculated) • Toff = 600s @ .18W • Ton = 15s @ 2.5W • Ton = spin-up time (2s) + Flash buffer flush time (13s) • Flash buffer size = 128MB • Transfer rate = 10MB/s • Pavg = ( 600*0.18 + 15*2.5 )/615 = 0.24W T > 600 s off 1.5 Pavg with disk spindle and seek in use = 1.2W ) W on 1 ( r e Power reduced 0 . 76 W w o 0.5 Pavg with flash write buffer = .24W P Time

14. Demo Results • View disk spindown times

15. Cold Boot Process • BIOS runs POST • Initializes the disk drive • Reads partition table from disk • Reads first logical block from bootable volume • Reads NTLDR which executes and loads Windows

16. Hybrid Disk Boot and Resume Windows Longhorn DRAM ATA Controller Motherboard 64-128MB NV Cache Hard Disk Controller • During shutdown or hibernate all the disk sectors needed to boot or resume are pinned into the NV cache • On next power on the BIOS POST runs and the disk is powered on but the spindle won’t be ready for 2-5 seconds • BIOS can read data from the NV cache and all boot process IO can be satisfied immediately • Once booted or resumed, Longhorn memory management fills system memory with most used disk data • Windows puts the HDD into NV Cache mode which spins-down the disk and results in write and read IOs to the NV Cache • Upon NV cache Read miss or the NV cache filling, the spindle is spun-up to satisfy Reads and flush cached write data to disk • The disk spins-down and continues to use the NV cache 2.5” HDD

17. Demo • Suspend/resume

18. System Design with Hybrid Hard Disk • Design objective: Enable fast boot/resume and save power • Standard motherboard ATA Interface • BIOS must exit POST rapidly • Fast memory check • Fast Chipset initialization • Initialize HDD early • BIOS must pass to boot loader quickly • Fast PNP detection • Boot HDD first in boot order • Main memory => 512MB

19. Other Design Approaches Considered • Flash memory device on the Motherboard • Potential corruption if cache and disk separated • Only provides partial functionality and requires significant additional design changes • Requires new disk driver that owns pinning and cache management • BIOS must be able to resolve cache/disk mapping before a driver loads • Flash memory and Hybrid disk controller on Motherboard • Potential corruption if controller and disk separated • Double processes all commands to the disk subsystem • Higher cost structure (additional ASIC)

20. HDD Partners • Samsung Electronics – Semiconductor Division • Flash product planning team worked with Microsoft on specification of the ATA command set • Samsung Semiconductor, together with Seoul National University (SNU) developed the “proof of concept” prototype Hybrid Hard Drive emulator • Samsung Electronics has started to develop commercial Hybrid Hard Disk drives • Hitachi • Worked with Microsoft on specification of the ATA command set • Provided feedback on Hybrid Hard Disk power, boot and MTBF models • Seagate • Worked with Microsoft on specification of the ATA command set

21. Community Resources • Windows Hardware & Driver Central (WHDC) • www.microsoft.com/whdc/default.mspx • Technical Communities • www.microsoft.com/communities/products/default.mspx • Non-Microsoft Community Sites • www.microsoft.com/communities/related/default.mspx • Microsoft Public Newsgroups • www.microsoft.com/communities/newsgroups • Technical Chats and Webcasts • www.microsoft.com/communities/chats/default.mspx • www.microsoft.com/webcasts • Microsoft Blogs • www.microsoft.com/communities/blogs

22. Relevant Mobile Platforms Presentations • TWDT05010 • Building a Longhorn-Ready Mobile PC • TWAR05001 • Longhorn Power Management Update • TWAR05002 • System Performance Assessment Tools For Windows Longhorn

23. Call To Action • HDD manufacturers should contact Microsoft for information on Hybrid Hard Disk support in Windows OS • Implementation Whitepaper • ATA Command Set • OEMs Contact Hybrid Hard Disk Partners to plan OEM certification process • OEMs need to include testing on Hybrid disk functionality at Longhorn Beta Two release • Contact MSHybrid @ Microsoft.com with any questions.