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Performance Modeling Hybrid Hard Drive Don Barnetson Associate Director, Flash Marketing Samsung Semiconductor, Inc Dec 6, 2005. Windows Longhorn. DRAM. ATA Controller. Motherboard. 64-128MB NV Cache. Hard Disk Controller. Hybrid Hard Drive – Key Values. Power Savings (90% Less)
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Performance Modeling Hybrid Hard Drive Don Barnetson Associate Director, Flash Marketing Samsung Semiconductor, Inc Dec 6, 2005 snowday\SEC_Draft_0305.ppt
Windows Longhorn DRAM ATA Controller Motherboard 64-128MB NV Cache Hard Disk Controller Hybrid Hard Drive – Key Values • Power Savings (90% Less) • Write buffer during normaloperation – 90% power reduction • Improved Reliability (tbd) • Duty cycle on platters near zero • HDD in non-operational mode • Fast Boot (5+ seconds faster) • Shutdown/Suspend: keyfiles written to flash cache • Power: files available 3-5 seconds before HDD • Realized performance is highlydependent on the flash used 2.5” HDD
Read disk & process STALL Future with HDD Desktop Active Future with HHD Read disk & process CACHE Desktop Active Depending on type of flash chosen: 2 – 6 seconds Resume – Today and Tomorrow Disk Power Disk Ready BIOS POST Read disk & process Today Desktop Active
FlashType ReadSpeed 64kBReadTime CachedFileSize TimeSavingsOverHDD 73nmSLC 29MB/s 2.2ms 29.6MB 7.35 s 90nmMLC 13MB/s 4.9ms 21.6MB 6.28 s MDOCH-1 8MB/s 8.1ms 16.5MB 5.6 s 73nmOneNAND 108MB/s 0.6ms 38.0MB 8.46 s Cached file size optimized to amount that can be loaded from flash during HDD spin-up time • Gains from flash in two ways: • Able to begin loading data ~3-5 seconds before HDD would be ready • Some flash types able to load data faster than HDD Mechanics of Resume Existing HDD – 100MB Suspend File Read 64kB Process 64kB 3.5ms 5.1ms Repeat 1,500 times
ResumeTimeSavings(higher isbetter) Net CycleperformanceNormalized toOneNAND 7.35 s +3.12 s 6.28 s +10.32 s 5.6 s +6.71 s 8.46 s 0 s Mechanics of Suspend FlashType CachedFileSize WriteSpeed SuspendTime(lower isbetter)* 73nmSLC 29.6MB 17MB/s 9.56 s 90nmMLC 21.6MB 2.5MB/s 15.68 s MDOCH-1 16.5MB 3.8MB/s 11.40 s 73nmOneNAND 38.0MB 17MB/s 7.55 s *Suspend file is unpinned during normal operation, drive is idle, write cache is half full at initiation of suspend step -> 4 s drive spin + 50% cache flush + write flash & HDD suspend files in parallel OneNAND provides substantially increased performancevs. all other flash solutions
Conclusions • Hybrid Hard Drive has Three Values • Power Savings due to write cache • Reliability enhancement due to lower duty cycle • Fast boot/resume due to data pinned to flash cache • Write caching does not challenge flash performance • Various solution provide similar results • Fast boot / suspend requires fast flash • OneNAND provides 3-10 s of savings vs. competingsolutions • OneNAND is the logical choice for Hybrid Hard Drive