Hybrid Disk Drives, the combination of a standard hard disk drive and NAND flash, were introduced in 2007 to an unreceptive market, so why are they making a resurgence today? This technology, which was well conceived but poorly implemented in its first generation, has now been implemented correctly and promises to sweep the PC hard drive market.

Objective Analysis' Hybrid Disk Drive study explains hybrid drive technical principals, its potential market, competing technologies, and how the NAND, PC, SSD, and HDD markets will all be impacted by this new twist on an old technology.

Readers will gain an understanding of all sides of the Hybrid Drive market, and will learn strategies to participate in the market. The 54-page study is based upon interviews with manufacturers of HDDs, NAND flash, hybrid drives and software, along with a solid understanding of computer architecture and data storage techniques. Twenty figures graphically illustrate important concepts and forecasts, and five tables give forecasts and other information.

TABLE OF CONTENTS


Executive Summary 
Introduction: Why Are Hybrid HDDs Needed?
   Memory Hierarchy Gap
   Why the Gap is Growing
   Filling the Gap with DRAM
   NAND Flash Prices Bring Changes
   A New NAND Step in the Hierarchy
   NAND SSDs Displace Enterprise HDDs
   Adding NAND to the Storage Hierarchy
History of the Hybrid Drive
   Early Stages 
   The HHDA
   Samsung
   Seagate 
   Vista Support 
   Rebirth of the Technology 
      Intel's Braidwood
      Seagate's Momentus XT Hybrid HDD
   Other Hybrid Drives
What's Different This Time? 
   Anatomy of a Hybrid Storage System 
   New Hybrids Use Internal Managers
   What Does this Manager Do?
Hybrid Hard Disk Drive Architecture
   Standard HDD Principals
   DRAM HDD Caches 
      DRAM Write Cache Risks
   NAND HDD Caches
      Nonvolatility
   NAND's Idiosyncratic Writes
   Hybrid Drives: A NAND Cache in an HDD 
Hybrid HDD Benefits
   Faster Data Access
   Reduced Power Consumption
   Greater Shock Tolerance
   Improved Reliability
   Benefit Summary 
   A Case Study: The Seagate Momentus
Can a Hybrid Drive Deliver "Instant-On"?
   Fast Boot Will Drive Demand 
How Much Will It Cost?
How NAND Costs will Add to HDD Costs
  Cost to the Consumer
Alternatives to Hybrid Drives
  Standard Hard Disk Drives (HDDs)
  Larger DRAM
  NAND Caches External to the HDD 
  Boot Drives
  Paired SSD & HDD 
     Automatic Data Placement
     Tiering Software
  Replacing the HDD with an SSD
Hybrid Drive Forecast
  Hybrid HDD Forecast
Impact to the NAND Market 
  Hybrid Share of Total NAND Market 
Summary
Methodology
Figures
Tables
Author
     Jim Handy

LIST OF FIGURES

Figure 1. The Gap in the Memory Hierarchy
Figure 2. The Gap Between DRAM and HDD is Growing
Figure 3. Filling the Speed Gap with DRAM
Figure 4. NAND Prices Have Dropped below DRAM's 
Figure 5. NAND Fills the Gap between HDD and DRAM 
Figure 6. Storage Hierarchy in a Typical Computing System 
Figure 7. Components of a Hybrid Storage System
Figure 8. Elements of a Hard Disk Drive
Figure 9. PC Total Power Savings from Hybrid HDD
Figure 10. Momentus XT Performance Approaches SSD Performance 
Figure 11. A Hybrid HDD with a Small Main Memory is Faster than an HDD with a Large DRAM 
Figure 12. Performance Improvement vs. Added Cost of All Options 
Figure 13. Momentus XT Performance Depends on Use History (PCMark Vantage HDD Scores)
Figure 14. Services Loaded During the Bootstrap Start of Windows XP 
Figure 15. SLC NAND Price per Gigabyte Forecast
Figure 16. Automatic Data Placement Greatly Outperforms Manual 
Figure 17. SYSmark Scores for HDD, SSD, and Cached Systems 
Figure 18. Hybrid HDD Unit Shipment Forecast
Figure 19. Optimistic/Pessimistic Forecasts for NAND Consumption in Hybrid Drives
Figure 20. Hybrid Share of Total NAND Market

LIST OF TABLES

Table 1. Status of Hybrid Drive's Features 
Table 2. Example Manual Data Placement Strategy for a Boot Drive
Table 3. Hybrid HDD Unit Shipments
Table 4. Forecast of Hybrid HDD Unit Shipments, Typical Size, and Manufacturing Cost
Table 5. Forecast of Hybrid HDD Unit Shipments, Typical Size, and Manufacturing Cost