Hybrid Hard Drives with Non-Volatile Flash and Longhorn - PowerPoint PPT Presentation

Hybrid Hard Drives with Non-Volatile Flash and Longhorn

Jack Creasey

Program ManagerHardware Innovation GroupMSHybrid@Microsoft.com

Microsoft Corporation

• 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

• 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

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

• Power Savings

• 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

NV

Cache

Add a non-volatile cache

Dram

Cache

ATA Interface

• 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

Up to 90% Power Saving

when powered down

Read and Write instantly while spindle stopped

Dram

Cache

ATA Interface

NV

Cache

• 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

• 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

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

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

• View disk spindown times

• 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

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

• Suspend/resume

• 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

• 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)

• 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

• 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

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

• 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.