Hybrid Hard Drives with NonVolatile Flash and Longhorn

1
Hybrid Hard Drives with Non-Volatile Flash and
Longhorn

• Jack Creasey
• Program ManagerHardware Innovation
  GroupMSHybrid_at_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 Fabrics Server/Enterprise
Leading platform supporting storage fabrics
Optimized platform features enabling new customer
scenarios in Personal Storage
Personal Storage Client/Consumer
Timely, comprehensive, quality platform support
for optical devices
Optical Platform Client/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?
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
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 data written

12
Power Saving Mode

• 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

• 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 _at_ .18W
• Ton 15s _at_ 2.5W
• Ton spin-up time (2s) Flash buffer flush time
  (13s)
• Flash buffer size 128MB
• Transfer rate 10MB/s
• Pavg ( 6000.18 152.5 )/615 0.24W

T

600
s
off
1.5
Pavg with disk spindle and seek in use 1.2W
)
W
on
1
(

r
e
w
Power reduced
0
.
76
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

• 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 wont 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.msp
  x
• 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 _at_ Microsoft.com with any
  questions.