SOLID STATE DRIVES Presented By: Manmath Agarwal IT-A 8th SEM
Contents•History • SSD Architecture•Solid State Drives • SSD Around us•NAND Flash Memory • Inter x25 SSD- an•SSD Elements Example 1. SSD Controller • Benefits of SSD 2. SSD Flash • SSD vs. HDD 3. SSD Interfaces • Application•SSD Storage Scheme
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. MLC ITEM SLC MLCVoltage 3.3V/1.8V 3.3VChip Size 0.12um 0.16umPage Size/Block Size 2KB/128KB 512B/32KB or 2KB/256KBAccess Time(Max.) 25us 70usEndurance 100K 10KCost per Bit more Comparatively lessWrite 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 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.
SSD Around Us Solid-State Disks (SSD) Mobile Media Players Embedded Thumb Disks Multimedia Systems Memory Cards
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
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 HDDSolid NAND Flash based Mechanism Type Magnetic Rotating platters64GB Density 80 GB75gm Weight 365gmRead: 100MB/s Performance Read: 59MB/sWrite: 80MB/s Write: 60MB/s1W Active Power Consumption 3.86W10-2000Hz Operating Vibration 22-350Hz1500G/0.5ms Shock Resistance 170G/).5ms0 °C– 70°C Operating Temperature 5°C– 55°CNone Acoustic Noise 0.3 dBMTBF > 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.