The Drive Interface Progress Cycle

Transcription

1 The Drive Interface Progress Cycle Dan Colegrove December 6, Hitachi Global Storage Technologies

2 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

3 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

4 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 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

5 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

6 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 2005 Hitachi Global Storage Technologies

7 Hybrid HDD What flash technology should be used? By: Esther Spanjer Director of Technical Marketing

8 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 2

9 Storage - looking into the future SAN HDD PVR Desktop Tablet PC SSD Telecommunications Blade Server Laptop Thin Client POS Data recording Rugged Laptop Hybrid 3

10 The Hybrid HDD concept Add a nonvolatile cache DRAM Cache NV Cache Why not large NV cache (2-4GB)? Store critical system info: registry, favorites, etc. ATA Interface Microsoft NV cache inside HDD 128MB recommended Stores frequently used sectors for fast boot and resume Supported in Vista Intel (Robson cache) NV Cache on motherboard Boot OS from flash Demo ed with 128MB 4

11 Advantages of Hybrid Hard Disk 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 5

12 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-integration Existing HDD controllers support NOR interface only, not NAND Performance Fast read performance for fast boot and resume time Fast write performance to reduce power consumption and fast time to enter hibernation No added reliability risk Low Cost Short TTM playing in consumer market 6

13 NVM options for Hybrid HDD Embedded Flash Disk Controller + flash in same package Raw NAND + HDD controller with NAND support Raw NAND + NAND controller 7

14 NAND Flash Market Landscape Future Flash Trends Compromising on reliability with every new process Different EDC/ECC is required Boot becomes slower and more complicated Compromising on performance Compromising on endurance Managing flash becomes more complex Better wear-leveling is crucial Compromising on data retention Code storage is a challenge Compromising on compatibility Different page sizes between different vendors Not always compatibility between processes and vendors 8

15 Embedded Flash Disk vs. Raw NAND Raw NAND Page Size PPP MLC 8 bit EDC # of planes Boot support Density per $ Compatibility 9

16 Embedded Flash Disk vs. Raw NAND Embedded Flash Drives (EFD) MLC & SLC Any Process Any Page Size Any OS Any Processor Single Software Density per $ Compatibility Boot support 10

17 EFD for Hybrid HDD Advantages Minimal 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 Disadvantages Slightly higher cost than raw NAND 11

18 HDD controller with NAND support Mobile vendors chipset support for Flash Chipsets NAND 200? MLC Support? 2007? 4KB Page Expected that HDD vendors 6 bit MLC will K SLC 2005 SMSG MLC 2005 face same time gap problems K SLC No Support MLC NAND 2K Page SLC

19 HDD controller with NAND support Advantages Low cost for raw NAND Minimal PCB space one chip solution Disadvantages Development 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 13

20 Raw NAND + NAND Controller Advantages Multi-source flash chip NAND controller supports various NAND flashes Disadvantages Multi-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 14

21 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 Performance Medium Fast Medium Reliability Medium High Low Flash Endurance Low High Low TTM Medium Fast Slow Support for best flash No Yes No TCO Medium Best Medium 15

22 Summary We re at crossroads in storage industry Who will dominate? HDD, SSD, Hybrid HDD? First prototypes Hybrid HDD demo ed by Samsung and Intel Flash Expertise will become critical Managing flash is becoming more and more complex Raw NAND has low cost, but many headaches Embedded Flash Disk Meets 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 16

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