SOLID STATE DRIVES

Presented By:Manmath Agarwal

IT-A8th SEM

Contents•History•Solid State Drives•NAND Flash Memory•SSD Elements

1. SSD Controller2. SSD Flash3. SSD Interfaces

•SSD Storage Scheme

• SSD Architecture• SSD Around us• Inter x25 SSD- an

Example• Benefits of SSD• SSD vs. HDD• Application

History• Storage Devices are evolved as the use of

machines is increasing. Punch Cards (in 1940s). Magnetic Tapes/Drives (in 1950s). Hard Drives. Solid State Drives.

Solid State Drive(SSD)

• SSD is an PC storage device that uses Solid State memory to store information.

• SSD uses non volatile NAND Flash Memory , which enables it to retain data when the power is removed.

NAND Flash Memory

• NAND Flash Memory is the key component of SSD.

• It is a specific type of EEPROM chip.• It has a grid of columns and rows with a cell

that has two transistors at each intersection as Control gate and Floating gate transistor.

• The principle of operation is based on MOSFETs.

Types of NAND Flash• Single Level Cell (SLC)• Multi Level Cell (MLC)

SLC vs. MLCITEM SLC MLC

Voltage 3.3V/1.8V 3.3V

Chip Size 0.12um 0.16um

Page Size/Block Size 2KB/128KB 512B/32KB or 2KB/256KB

Access Time(Max.) 25us 70us

Endurance 100K 10K

Cost per Bit more Comparatively less

Write Data Rate 8MB/s+ 1.5MB/s

SSD ElementsSSD consists of basically three elements:• SSD Controller.• SSD Flash.• SSD Interface.

SSD Controller

• Flash controller includes the electronics that bridge the Flash memory components to the SSD input/output interfaces.

• The controller is an embedded processor that executes firmware-level software.

SSD Controller Block Diagram

• Processor• ECC• Flash Controller• DRAM Controller• I/O Interface• Controller Memory• Chip Configuration

SSD Flash

• Solid State Flash memory is available using NAND technology.

• NAND Flash components come in densities from 1Gb (gigabit) to 64Gb per chip.

• NAND Flash components have structures called pages and blocks.

• There is an Error Correction Code (ECC) associated with each sector.

• NAND Flash has a limited rewrite endurance of about 1,000,000 times per block.

SSD Flash Block Diagram

• Data Interface • I/O Controller• Control Logic• Address Register• Data/Cache register• Status register• Row/Column Decode• Flash Array

SSD Interface• Interface is used to connect the SSD with the

computer.• Also, since SDDs are generally used in

conjunction with magnetic disk drives, a common mass storage bus interface is used in most cases.

• SSD are available with a variety of system interfaces based primarily on the performance requirements: Serial ATA Serial attached SCSI

Fiber Channel USB

SSD Storage Scheme

• Groups of NAND flash cells are organized into pages and these pages are organized into blocks.

• Read and write operations can be performed on pages, but erase operations can only be performed at the block level.

• This means that when rewriting a page, the entire block must be erased first.

• The SSD controller manages this process.

• Page Size is

SSD Architecture

SSD Around Us

Mobile Media PlayersMobile Media PlayersSolid-State Disks (SSD)Solid-State Disks (SSD)

Thumb DisksThumb Disks Multimedia Memory Cards

Multimedia Memory Cards

Embedded Systems

Embedded Systems

Intel x25 SSD- An Example

• Certified for 25 MB/s read speed and 70 MB/s write speed.

• MLS SSD standard.• 10-channel memory controller.• Each channel is “responsible” for two

memory chips.• http://www.insidehw.com/Reviews/

Storage/Intel-X25-M-SSD.html

Intel x25 SSD

Benefits of SSD

• Faster start up of Solid State Drive• Faster access• Faster application launch time• More energy efficient• More reliable• More robust under extreme conditions• Lighter

SSD vs. HDD2.5” SATA 3.3 Gbps SSD 2.5” SATA 3.8 Gbps HDD

Solid NAND Flash based Mechanism Type Magnetic Rotating platters

64GB Density 80 GB

75gm Weight 365gm

Read: 100MB/s Write: 80MB/s

Performance Read: 59MB/s Write: 60MB/s

1W Active Power Consumption 3.86W

10-2000Hz Operating Vibration 22-350Hz

1500G/0.5ms Shock Resistance 170G/).5ms

0 °C– 70°C Operating Temperature 5°C– 55°C

None Acoustic Noise 0.3 dB

MTBF > 2M hours Endurance MTBF < 0.7M hours

Application

• SSDs were mainly used in those aspects of mission critical applications where the speed of the storage system needed to be as fast as possible.

• Organizations that can benefit from faster access of system data include equity trading companies, telecommunication corporations, and video streaming.

• SSD are used as cache at server side of Enterprises.

References•http://en.wikipedia.org/wiki/Solid_state_drives•http://www.storagereview.com/ssd_reference_guide•http://electronics.howstuffworks.com/flash-memory.htm•http://i.dell.com/sites/content/business/solutions/whitepapers/en/Documents/wp-2009-SSD.pdf

Thank You.

Queries ???

•SSD Architecture•SSD Around us•Inter x25 SSD- an Example•Benefits of SSD•SSD vs. HDD•Application