the drive interface progress cycle · embedded flash disk raw nand + hdd controller with nand...
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© 2005 Hitachi Global Storage Technologies
The Drive Interface Progress Cycle
Dan Colegrove
December 6, 2005
© 2005 Hitachi Global Storage Technologies
Interface Development Cycle
New Interface Feature Development Cycle:•Development of the New Feature (Specification/Standard)
•Prototypes •First Generation Products •Refinement of Standard/Specification •Conversion to New Products / Volume Ramp•Phase Out of Older Technology •Development of Next Generation
© 2005 Hitachi Global Storage Technologies
Interface Development Cycle
Disk drive interface serialization was a major shift, ATA to SATA, Parallel SCSI to SAS.•SAS and SATA are not plug compatible with parallel equivalents
– Large investment by both drive manufacturers and OEMS to switch.
– Long transition •Serialization of ATA and SCSI interfaces allow new applications
– Large arrays with both SAS and SATA drives
© 2005 Hitachi Global Storage Technologies
Interface Development Cycle
SATA and SAS• Transition to SATA is proceeding• SAS provides support for both SAS and SATA storage arrays so it will transition
somewhat faster than SATA.
A period of stability to allow drive manufacturers and OEMs to profit from the investment in the conversion to serial.
A large jump in interface speed with SATA; SAS not as much. • SATA 133 Mbytes/s -> 300 Mbytes/s• SAS 320 Mbytes/s split over up to 15 drives to 300 Mbytes/s per drive
SATA 3 Gigabit greatly exceeds drive data rates in Desktop/Mobile• 3 Gigabit should be sufficient to beyond 2011.
SAS needs additional speed in the expander network, but not to the drive. • Enterprise class drives will not need more than 3 Gigabit until 2011• Fortunately the transition to serial and a branching expander network will allow higher
bandwidth connections to storage arrays without requiring support by individual drives
© 2005 Hitachi Global Storage Technologies
Constant Stream of New Features
Steady progress in new features and functions• ATA
– SATA Queuing – Large Physical Sector Support (4K) – AV Streaming Support
• SCSI– End to End Data Protection
• Software Support for new features takes time, but less than for a physical change. – Time dependant on the degree of OS/Driver/Application impact– Some Linked to OS releases (e. g. Windows Vista)– Prioritized by OEM and End User Interest.
1. End User Perceptible new Feature (Capacity) (AV Streaming) (SAS support for SATA) End User Perceptible Performance Increase (RPM) (SATA Queuing)
2. Cost Reduction (4K)3. Technology Change (SATA) (SAS)
© 2005 Hitachi Global Storage Technologies
Conclusion
SATA was a big change
SAS was big change
It will take time to complete the transition
There is little opportunity for a another major change until the transition to SATA and SAS is complete
New interface features will continue to be developed• Time to implementation depends on level of OS/BIOS/Driver support
required
Hybrid HDD What flash technology should be used?
By: Esther SpanjerDirector of Technical Marketing
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Agenda
Introduction to Hybrid HDD
Requirements for NV Cache
NVM options for NV Cache
Embedded Flash Disk
Raw NAND + HDD controller with NAND support
Raw NAND + NAND controller + HDD controller
Comparing alternatives
Summary
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Storage - looking into the future
Telecommunications
HDD
SSDTablet PC
Desktop
PVR
SAN
Rugged Laptop
Data recording
POS
Laptop
Thin Client
Blade Server
Hybrid
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The Hybrid HDD concept
DRAMCache
NVCache
Add a non-volatile cache
ATA Interface
MicrosoftNV cache inside HDD
128MB recommended
Stores frequently used sectors for fast boot and resume
Supported in Vista
Intel (Robson cache)NV Cache on motherboardBoot OS from flashDemo’ed with 128MB
Why not large NV cache (2-4GB)?
Store critical system info: registry, favorites, etc.
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Advantages of Hybrid Hard Disk
Reduce Power ConsumptionRead and Write disk data while drive is in a low power state with the spindle stopped
Faster Boot and ResumeInstant access to data in NV Cache
Higher ReliabilityBetter shock resistance
Lower operating duty cycle
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Requirements for NV cache
Capacity: 128MB-1GB (up to 4GB in future?)
Small size - Limited space on the HDD PCB or motherboard
Multi-source
Ease-of-integrationExisting HDD controllers support NOR interface only, not NAND
PerformanceFast read performance for fast boot and resume time
Fast write performance to reduce power consumption and fast timeto enter hibernation
No added reliability risk
Low Cost
Short TTM – playing in consumer market
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NVM options for Hybrid HDD
Embedded Flash DiskController + flash in same package
Raw NAND + HDD controller with NAND support
Raw NAND + NAND controller
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NAND Flash Market LandscapeFuture Flash Trends
Compromising on reliability with every new processDifferent EDC/ECC is required
Boot becomes slower and more complicated
Compromising on performance
Compromising on enduranceBetter wear-leveling is crucial
Compromising on data retentionCode storage is a challenge
Compromising on compatibilityDifferent page sizes between different vendors
Not always compatibility between processes and vendors
Managing flash becomes more complex
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Embedded Flash Disk vs. Raw NAND
Raw NAND
Density per $ Compatibility
Page Size
PPP
MLC
8 bit EDC
# of planes
Boot support
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Density per $ Compatibility
Embedded Flash Disk vs. Raw NAND
Embedded Flash Drives (EFD)
MLC & SLC
Any Process
Any Page Size
Any OS
Any Processor
Single Software
Boot support
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EFD for Hybrid HDD
AdvantagesMinimal PCB space – one chip solution
Provides NOR interface, no need for new HDD controller
Software already provided by flash manufacturer better TTM
Alleviates all flash “headaches”
Multi-source (some vendors)
Best access to latest flash technology without redesigning HDD
DisadvantagesSlightly higher cost than raw NAND
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HDD controller with NAND support
Mobile vendors chipset support for Flash
SLC
2K Page
MLC NAND
6 bit MLC
4KB Page
No Support
0.5K SLC
2K SLCSMSG MLC
2001
2002
2003
2006
2007
2004
2005
2001
2002
2003
2006
2007
2004
2005
MLC Support?
Chipsets NAND
200?
?Expected that HDD vendors will face same time gap problems
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HDD controller with NAND support
AdvantagesLow cost for raw NAND
Minimal PCB space – one chip solution
DisadvantagesDevelopment time longer
R&D cost higher (new ASIC development)
Difficult to keep up with huge flash offering: SLC/MLC, 90/70/50nm, large/small block, different flash vendors etc
Decreasing flash geometry less reliable flash more knowledge of HDD vendor required to support
Flash management software – who to provide?
Flash chips not compatible between flash vendors no true second source
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Raw NAND + NAND Controller
AdvantagesMulti-source flash chip NAND controller supports various NAND flashes
DisadvantagesMulti-source for NAND controller
More PCB space – 2 chip solution
Additional cost for NAND controller
Software support – who to provide?
Time gap in following latest flash technology
When using MLC flash – reliability might be compromised
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Comparing Alternatives
Raw NAND+
NAND controller
Embedded Flash Disk
Raw NAND+
HDD controller
Footprint 2 chip solution 1 chip solution 1 chip solution
Multi source Limited Yes Very limited
Ease-of-Integration
Hard Easy Very Hard
Flash Endurance Low High Low
Performance Medium Fast Medium
TTM Medium Fast Slow
Support for best flash
No Yes No
TCO Medium Best Medium
Reliability Medium High Low
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Summary
We’re at crossroads in storage industryWho will dominate? HDD, SSD, Hybrid HDD?
First prototypes Hybrid HDD demo’ed by Samsung and Intel
Flash Expertise will become criticalManaging flash is becoming more and more complex
Raw NAND has low cost, but many headaches
Embedded Flash DiskMeets the Hybrid HDD requirements for performance, reliability and ease-of-integration
Offers real multi-source solution
Small footprint
Fastest time to market
Best option to use latest flash technology without need for redesign
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