Intel® NAND Flash Memory for Intel® Turbo Memory

White PaperIntel® Flash Memory Intel® NAND

Flash Memory for Intel® Turbo Memory

Intel® NAND Flash Memory for Intel® Turbo Memory White Paper

Introduction

OverviewIntel has introduced a new non-volatile memory (NVM) layer into thememory hierarchy in the mobile computing platform. This new NVMlayer and technology is a hard disk drive cache. This new non-volatilehard disk drive cache memory layer was developed in a mini PCI-expressmemory card form factor that can be inserted in the back of a laptopmuch like Intel’s Wireless LAN (WLAN) solution for Intel® Centrino®mobile technology. The new non-volatile memory layer is now a prod-uct called Intel® Turbo Memory. It consists of an Intel Turbo Memorycontroller ASIC (Application Specific Integrated Circuit) chip and twoIntel NAND flash non-volatile memory components that enable fasterresume to productivity after hibernate, providing additional power savings by limiting hard disk drive accesses and increasing application responsiveness for a richer user experience.

The Intel Turbo Memory card on the new mobile computing platformsoperating on Windows Vista* OS support both Microsoft's ReadyDrive*and ReadyBoost* features in one single unit.

The capabilities and features of the Intel Turbo Memory card areaccomplished by utilizing a fast PCI express bus to efficiently movedata between the Intel Turbo Memory card and the CPU data requestsrather through the slower higher power hard disk drive path.

The application performance acceleration is attributed to getting datavia a faster 250MB/s PCI express bus to and from a higher perform-ance silicon NAND flash memory media rather than a slower rotatingmagnetic hard disk drive. The Intel® Matrix Storage Manager (IMSM)software in conjunction with the Intel Turbo Memory firmware driversjudiciously control the reads and the writes to the hard disk drive limit-ing the hard disk drive power consumption and extending the wear andthe life of the hard drive.

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Figure 2: Intel® Turbo Memory Block Diagram

HDD

Intel®Turbo

MemoryController

Intel® TurboMemory Card

NewMemory

Hierarchy

NVM CacheBIOS

BIOS

ICH

MCH

CPU

DRAM

Disk

Control Signals

x16 Data Bus x8

x8

MainMemory

PCI-e PCI-eIntel®NANDFlash

Memory

Intel®Turbo Memory

Controller

Intel®NAND Flash

Memory

Intel®NAND Flash

Memory

HDD

Intel®Turbo

MemoryController


NewMemory

Hierarchy

NVM CacheBIOS

BIOS

ICH

MCH

CPU

DRAM

Disk

Control Signals

x16 Data Bus x8

x8

MainMemory


Memory

Intel®Turbo Memory

Controller

Intel®NAND Flash

Memory

Intel®NAND Flash

Memory

Figure 1: New Non-Volatile Memory Layer in the PC Computing Platform

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The Four Key Tenantsof the Intel® TurboMemory CardThe four key tenants of the Intel® Turbo Memory card are:

• A complete understanding of the PC system memory and the

HDD (Hard Disk Drive) usage model

• Platform and memory component reliability requirements

• Platform memory performance needs

• Thorough hardware and software validation of the complete

platform solution

All four of these key tenants will be discussed in detail in this paper.

Intel has extended its PC system (DRAM) memory and platform HDD

expertise in developing the Intel Turbo Memory card. The introduc-

tion of this new non-volatile memory disk caching layer into the

overall PC memory platform hierarchy is revolutionary in principle and

the application of NAND flash memory. None of these four tenants

can be compromised to deliver and ensure a solid solution such as

the Intels Turbo Memory card.

PC Platform Memory Usage Model

Understanding the complete PC platform memory usage model and

hierarchy from the deepest levels of the CPU registries and caches

to the remotest level of hard disk drive storage is essential in know-

ing how to improve the overall platform performance, knowing what

the right solution is, as well as the right implementation of the solu-

tion. The Intel Turbo Memory card uses the NAND flash dramatically

different than the traditional use of NAND flash memory, i.e., in

memory cards and USB drives.

The traditional use for NAND flash devices in USB drives and in

other memory card form factors has been primarily for storage of

large files such as digital pictures, music, or a large document. The

usage of these devices has been for occasional writes and reads, as

for example, in a digital camera, where these captured and stored

data files (images) are transferred via a memory card to a personal

computer for image processing, email distribution, printing, or

storage. This typical usage model of NAND flash in the consumer

memory card environment is dramatically different from the PC

computing environment where the Intel Turbo Memory card is used.

The difference between the two memory card usage models and

devices are listed in the following table:

Figure 3: The 4 Key Tenants of the Intel® Turbo Memory Card

Figure 4: Consumer Data Storage Usage Model

White Paper Intel® NAND Flash Memory for Robson Technology

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These NAND usage model differences between the consumer mem-

ory card data storage and PC computing requires extensive research

in workload scenario analysis. The development of key wear leveling

algorithms is essential to enable the NAND flash and the platform to

work reliably over the product life. Once these NAND flash caching

usage models and work loads were done, close relationships with

the Microsoft Vista* OS and Intel software/firmware developers

were needed to optimize the Intel Turbo Memory controller and wear

leveling algorithm of the NAND flash Memory to further the Intel

Turbo Memory card product performance.

Reliability

The PC computing platform, the NAND flash usage model, and the

application workloads define and determine the platform design and

operational bounds of the Intel Turbo Memory card. The major relia-

bility elements essential to the success of the memory card are:

• Intel® Turbo Memory controller to manage the NAND flash

• NAND flash wear leveling algorithm and firmware

• Intel® NAND flash memory component reliability

All three reliability elements listed above must be extensively tested

individually and on the platform to ensure it meets the product life

requirements.

Intel® Turbo Memory Controller Manages the

Intel® NAND Flash

The Intel Turbo Memory controller manages the NAND flash and the

PCI Express bus while handling the Operating System (OS) service

calls for cached data reads and writes. As with any NAND based

memory product solution, the NAND flash memory controller is the

key in executing the NAND flash wear leveling algorithm, managing

the reads, writes, erases, and performing the ECC (Error Correction

Code) as needed.

The Intel Turbo Memory controller has a dual responsibility to man-

age the NAND usage and keeping extensive “book keeping” of the

NAND reliability statistics. These usage statistics includes the num-

ber of page reads, page writes, block erases, and the reliability statis-

tics include initial and subsequent development of bad blocks over

time, block retirement, and bit error rates. All these vital statistics are

used to manage the NAND flash over the life of the Intel Turbo

Memory card.

Model Attribute

Applications

File Size

Performance

Reliability

PC Computing

• Random small file writes

• References small amounts

of data

• 50% are 8 Sectors (4KB)

• Avg. Size: 44 Sectors (~20KB)

• Fast small random reads

• Fast small random writes

• Extensive reads and writes

• Intensive daily and hourly

computational usage

Consumer Data Storage

• Sequential large file writes

• Large Files > 1MB

• Fast large file writes

• Frequent writes

• Seldom read

• Occasional use

Intel® Turbo Memory Card Usage Model Comparison

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Intel Developed Flash Wear Leveling Algorithm and

Firmware IP

Extensive studies have been done on various usage models for the

light, moderate, and heavy mobile PC users and their corresponding

user application workloads to determine the optimal wear leveling

algorithm. These studies were essential in establishing and fitting

the new Intel® Turbo Memory layer into the PC platform hierarchy

and correspondingly outlining the reliability requirements of the

Intel®NAND Flash Memory. While many NAND flash suppliers specify

the same reliability specifications such as their 100K program erase

specifications and their data retention capabilities, each supplier sat-

isfies the requirements differently. In that regard, the Intel Turbo

Memory controller and wear leveling algorithm was specifically

fine-tuned to Intels NAND Flash Memory.

With NAND flash moving into this new rigorous and demanding com-

puting environment, the Intel Turbo Memory controller must execute

the NAND flash wear leveling algorithm to ensure a healthy and

robust product life for the Intel Turbo Memory Card. The wear level-

ing algorithm must comprehend not only the usage statistics of the

NAND flash but also track the key reliability statistics. The wear lev-

eling algorithm must track the many known failure mechanisms

known to all NAND flash in the industry that include the following:

• Program Disturb

• Read Disturb

• Program and Erase Cycles

• Data Retention

• Bit Error Rate (BER)

• Block Wear and Retirement over Usage and Time

Ground breaking NAND wear leveling algorithms were developed

and tested to ensure the NAND flash reliability to the various usage

models. Attributes of the wear leveling algorithm had to compre-

hend the demanding data caching performance and data through-

put requirements while managing the following:

• Maintaining low power consumption

• Managing memory space for incoming large and small files

• Determining and managing Intel Turbo Memory card foreground

and background operations

• Even wear of the NAND flash memory blocks

• Intel Turbo Memory card separation issues with the platform and

hard disk drive

The above graph illustrates the wear leveling algorithm results high-

lighting the evenness and efficiency of memory block usage with

the flat curve of a sample work load study. The graph shows a

2.5% difference in block erase count between the mean and peak

usage activity.

Figure 5: Demonstrated NAND Memory Wear Leveling Effectiveness


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In the end, the Intel® Turbo Memory wear leveling algorithm

and firmware for the memory card maximizes Intel's NAND flash

performance and capability.

Intel® NAND Flash Memory

Intel's SLC (Single Level Cell) NAND flash memory is one of the key

ingredients to the development of the Intel Turbo Memory card. All

of its intricate performance to read, write, erase, and respective

reliability capabilities have been woven in the development of the

NAND wear leveling algorithm and the Intel Turbo Memory controller.

The Intel® NAND Flash Memory reliability in respect to, Program and

Read Disturb, Partial Page Writes, Program and erase cycling, Bit Error

Rate (BER) and ECC, Block “0” reliability capabilities, Bad Block

Management, Data retention have been evaluated and built into

Intel's NAND flash wear leveling algorithms and ECC schemes to

provide the highest quality and integrity of data to the computing

environment.

Contrary to industry NAND flash, Intel’s NAND flash memory

provides an additional advanced command set that offers more

capability and performance. These advanced commands include

the following:

• Random Data Read Within a Page Buffer

• Write and Read Cache Mode

• OTP (One Time Programmable)

• Two Plane Commands (Read, Program, and Erase Operation,

and Interleave Die Operation)

Intel® Turbo Memory Card Performance

The Intel Turbo Memory card provides the user with more perform-

ance with their mobile laptop PC by supplying data faster to the CPU

in all modes of operation, active, resumes to productivity from hiber-

nate, and booting all resulting in a better and more satisfying user

experience. This improved performance is attributed to the memory

card architecture and operating on a faster 250 MB/s PCI Express

bus rather than on a slower higher power USB or other system bus.

The memory card architecture was designed to deliver better per-

formance by taking advantage of the power of parallelism that uti-

lizes 2 Intel® NAND Flash Memory components that are addressed,

written, and read in an interleaved x16 parallel data path with the

Intel Turbo Memory controller.

The Intel Turbo Memory card design has been optimized for perform-

ance to Intel's SLC (Single Level Cell) NAND flash bus command set,

setup and hold edge timings, and I/O edge timings to squeeze out

any wasted bus time. Combined with a high performance Intel Turbo

Memory controller and Intel NAND flash component performance,

the Intel Turbo Memory card can deliver visible improvements in user

applications experience, resumes to productivity from hibernates,

and additional battery power savings.

HDD

Intel®Turbo

MemoryController


NewMemory

Hierarchy

NVM CacheBIOS

BIOS

ICH

MCH

CPU

DRAM

Disk

Control Signals

x16 Data Bus x8

x8

MainMemory


Memory

Intel®Turbo Memory

Controller

Intel®NAND Flash

Memory

Intel®NAND Flash

Memory

Figure 6: Intel® NAND Flash Memory

Figure 7: Intel® Turbo Memory Card Block Diagram

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Platform Validation of Memory Hardware and Software

The last key tenant and the last task in completing the Intel® Turbo

Memory card design and development is a complete product

validation between the hardware and the software. Extensive

validation at the hardware and software level is needed to ensure

a robust product.

Hardware Validation

Component read, write, and erase operation timing between the

Intel Turbo Memory controller to Intel NAND flash was extensively

evaluated and validated. Extensive measurements and characteriza-

tion data gathering was completed to ensure all the NAND flash

command set, I/O timings, and read, write, and erase datasheet

specifications were met.

Platform Validation

The Intel Turbo Memory card received approval from the PCI-e stan-

dards body by meeting standards certifications and achieving stan-

dards compliance with its high speed PCI Express interface. Data

integrity and I/O performance tests were tested to meet PCI specifi-

cations. Participation in the PCI-Express “plug feast” test were also

completed to ensure compatibility across platforms.

Software and Firmware Validation

Validation testing of Intel's NAND Flash Memory wear leveling algo-

rithm and Intel Turbo Memory software drivers with Microsoft's

Vista* OS release was thoroughly conducted to ensure system

robustness. Integrating the Intel Turbo Memory card to the platform

at the software level required close examination and coordination of

the Vista* OS, graphics chipset (GMCH) and IO chipset (ICH) firmware,

platform BIOS, and Intel's matrix storage manager software.

To validate Intel's NAND Flash Memory wear leveling algorithm, a

specific Intel® NAND Flash Memory RDT (Reliability Demonstration

Test) was designed and tested with PC mobile laptops reading, pro-

gramming, and erasing the NAND flash with work loads running

24x7 at accelerated temperatures. During the course of the RDT, the

NAND flash reliability statistics were monitored to resolve, demon-

strate and prove a 2.5 million hour MTBF product life capability.

High Volume Manufacturing (HVM) Product Qualification

Intel's Turbo Memory card has gone through an internal HVM memo-

ry card validation. Moreover, each of the respective silicon compo-

nents, Intel Turbo Memory controller and Intel NAND Flash Memory

also were subjected to qualification. Finally, the Intel Turbo Memory

card also went through a rigorous high volume manufacturing (HVM)

product qualification that includes the following:

• Card (board) Manufacturing: Solder Joint Reliability, Temperature

cycling, Power cycling, Flex, Shock & Vibration, Operational

Shock & Vibration

• Board Level Evaluations for ESD and EMI

(Electro-Magnetic Interference)

• Quality and Environmental Standards Tested to Meet: ROHS, UL,

and PCI Express

In the end, a qualified Intel Turbo Memory card resulted after

an extensive product qualification processes. This ensured a solid

product to meet the platform usage model of five years.

SummaryExtensive research into the mobile PC platform memory hierarchy,

usage model, and work load was done to develop the Intel Turbo

Memory card. The four key tenants responsible in producing the

Intel Turbo Memory card are:

1. Memory usage model and work load analysis

2. Reliable wear leveling algorithm to ensure product life

3. Intel Turbo Memory card performance

4. Complete platform software and hardware validation

Figure 8: Intel® Turbo Memory Card

Intel, the Intel logo, Intel. Leap ahead and Intel. Leap ahead logo are trademarks of Intel Corporation in the U.S. and other countries.

*Other names and brands may be claimed as the property of others. Information regarding third-party products is provided solely for educational purposes. Intel is notresponsible for the performance or support of third-party products and does not make any representations or warranties whatsoever regarding quality, reliability, functionality, or compatibility of these devices or products.

Copyright © 2007 Intel Corporation. All Rights Reserved.

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Intel® NAND Flash Memory for Intel® Turbo Memory