Solid State Drives ( SSD ) By: Sumeet Dinkar Dalvi MCA-II Sem-III Roll No: 09 2012-2013

Contents Introduction Development & history Architecture & design Myths With SSD’s Operations of SSD SSD vs. HDD Advantages Disadvantages Summary

introduction The SSD (Solid State Drive) : sometimes improperly referred to as “Solid State Disk or an electric disk” is a data storage device that uses integrated circuit assemblies as memory to store data persistently. SSD technology uses electronic interfaces compatible with traditional block (I/O) hard disk drives.

SSDs do not employ any moving mechanical components, which distinguishes them from traditional magnetic disks such as hard disk drives (HDDs) or floppy disks, which are electromechanical devices containing spinning disks and movable read/write heads. Compared with electromechanical disks, SSDs are typically less susceptible to physical shock, are silent, and have lower access time

most SSDs use NAND-based flash memory, which retains data without power. For applications requiring fast access, but not necessarily data persistence after power loss, SSDs may be constructed from random-access memory (RAM). Such devices may employ separate power sources, such as batteries, to maintain data after power loss.

Development And History SSD’s using RAM : The origins of SSDs came from the 1950s and used two similar technologies: magnetic core memory and card capacitor read-only store (CCROS).[These auxiliary memory units, as they were called at the time, emerged during the era of vacuum tube computers. But with the introduction of cheaper drum storage units, their use was discontinued. In the late 1970s, General Instruments produced an electrically alterable ROM (EAROM) which operated somewhat like the later NAND flash memory. Unfortunately, a ten-year life was not achievable and many companies abandoned the technology.

In 1978, Texas Memory Systems introduced a 16 kilobyte RAM solid-state drive The Sharp PC-5000 introduced in 1983, used 128 kilobyte solid-state storage cartridges, containing bubble memory. In 1986, Santa Clara Systems introduced RAM (batram), the 4 megabyte mass storage system expandable to 20 MB using 4 MB memory modules. The package included a rechargeable battery to preserve the memory chip contents when the array was not powered. In 1987 saw the entry of EMC Corporation (EMC) into the SSD market, with drives introduced for the mini-computer.

Flash based SSD’s : In 1995, M-Systems introduced flash-based solid-state drives. They had the advantage of not requiring batteries to maintain the data in the memory but were not as fast as the DRAM-based solutions. In 1999, Bit MICRO made flash-based SSDs, including an 18 GB 3.5-inch SSD. In 2007, Fusion-io announced a PCIe-based SSD with 10,000  i/o operations per second (IOPS) of performance in a single card, with capacities up to 320 gigabytes In 2009, OCZ Technology demonstrated a 1 terabyte(TB) flash SSD using a PCI

It achieved a maximum write speed of 654 megabytes per second (MB/s) and maximum read speed of 712 MB/s. In December 2009, Micron Technology announced the world's first SSD using a 6 gigabits per second SATA interface.

Architecture & Design The key components of an SSD are 1: the controller 2: the memory The primary memory component in an SSD had been DRAM volatile memory since they were first developed, but since 2009 it is more commonly NAND flash non-volatile memory, Other components play a less significant role in the operation of the SSD and vary among manufacturers.

Controller : Every SSD includes a controller that incorporates the electronics that bridge the NAND memory components to the host computer. It is one of the most important factors of SSD performance. Functions performed by the controller Are: 1. Error correction (ECC) 2. Wear leveling 3. Bad block mapping 4. Read scrubbing and read disturb management 5. Read and write caching 6. Garbage collection 7. Encryption

Memory: Flash Memory Based 2 DRAM Based Most SSD manufacturers use non-volatile NAND flash memory in the construction of their SSDs because of the lower cost compared with DRAM Lower priced drives usually use multi-level cell (MLC) flash memory, which is slower and less reliable than single-level cell (SLC) flash memory. 2 DRAM Based SSDs based on DRAM are characterized by ultrafast data access, generally less than 10 microseconds Price is high due to use of DRAM’s.

SSD logic components:

Myths with SSD’s : Solid state drives are too expensive for mainstream computing Today, the proven performance of MLC NAND-based SSDs is enabling more consumer-oriented prices. SSDs for notebook computers are most suitable for users who value increased reliability, ruggedness and performance. All SSDs have similar performance there can be a significant difference in performance from one SSD to another SSD capacities are too small SSDs are now available in many capacities, including high-capacity drives of 256GB and 512GB for mobile computer users.

SSDs will replace all hard disk drives Hard disk drives store data more safely and are more dependable than solid state drives With no mechanical parts, SSDs are less likely to suffer from unexpected drive failure than HDDs. SSDs will replace all hard disk drives SSDs and HDDs will coexist.

Operations on SSD: Read : Write : Block erasure : 25μs from page to data register 100μs transfer in the serial line Write : Sequentially with in a block Block must be erased before writing 200μs from register into flash cells Block erasure : 1.5ms ( 25μs for reading a page) Finite number of erase-write cycles

Comparison of SDD’s With HDD'S : Start Up Time : For SSD – Almost instantaneous; no mechanical components to prepare. May need a few milliseconds to come out of an automatic power-saving mode. For HDD – Disk spin-up may take several seconds. A system with many drives may need to stagger spin-up to limit peak power drawn, which is briefly high when an HDD is first started.

Random access time: For SSD - About 0.1 ms - many times faster than HDDs because data is accessed directly from the flash memory For HDD – Ranges from 2.9 (high end server drive) to 12 ms (laptop HDD) due to the need to move the heads and wait for the data to rotate under the read/write head

Read latency time : For SSD - Generally low because the data can be read directly from any location. In applications where hard disk seeks are the limiting factor, this results in faster boot and application launch times. For HDD – Generally high since the mechanical components require additional time to get aligned

Data transfer rate : For SSD – In consumer products the maximum transfer rate typically ranges from about 100 MB/s to 500 MB/s, depending on the disk. Enterprise market offers devices with multi-gigabyte per second throughput For HDD - Once the head is positioned, when reading or writing a continuous track, an enterprise HDD can transfer data at about 140 MB/s. However accessing fragmented data implies a severe performance penalty. Data transfer rate depends also upon rotational speed, which can range from 4,200 to 15,000 rpm. and also upon the track

Consistent read performance : For SSD – Read performance does not change based on where data is stored on an SSD For HDD – If data from different areas of the platter must be accessed, as with fragmented files, response times will be increased by the need to seek each fragment.

Noise : For SSD – SSDs have no moving parts and therefore are basically silent. For HDD – HDDs have moving parts (heads, actuator, and spindle motor) and make some sound; noise levels vary between models, but can be significant (while often much lower than the sound

Susceptibility to environmental factors : For SSD – No moving parts, very resistant to shock and vibration For HDD – Heads floating above rapidly rotating platters are susceptible to shock and vibration

Power consumption : For SSD – High performance flash-based SSDs generally require half to a third of the power of HDDs. High-performance DRAM SSDs generally require as much power as HDDs, and must be connected to power even when the rest of the system is shut down For HDD – The lowest-power HDDs (1.8" size) can use as little as 0.35 watts.2.5" drives typically use 2 to 5 watts. The highest-performance 3.5" drives can use up to about 20 watts

Read/write performance symmetry : For SSD – Less expensive SSDs typically have write speeds significantly lower than their read speeds. Higher performing SSDs have similar read and write speeds. For HDD – HDDs generally have slightly lower write speeds than their read speeds.

Temperature control : For SSD – SSDs do not usually require any special cooling and can tolerate higher temperatures than HDDs. For HDD – In practice most hard drives are used without special arrangements for cooling.

Cost per capacity : For SSD – NAND flash SSDs cost approximately US$0.65 per GB For HDD – HDDs cost about US$0.05 per GB for 3.5 inch and $0.10 per GB for 2.5 inch drives

Advantages of SSD’s: Do not makes noise. Faster start-up Low power consumption Fast fetching of data Fast read /write operations Extremely low read latency No any moving parts Large storage capacity Do not fail mechanically

Disadvantages of SSD’s: Cost significantly more per unit capacity Slower write speeds because of the erase blocks are becoming larger and larger(1.5 ms per erase) High capacity SSDs may have significant higher power requirements

Example of the SSD: 1 die = 4 planes 1 plane = 2048 blocks 1 block = 64 pages 1 page = 4KB Dies can operate independently Reading and programming is performed on a page basis, erasure can only be performed on a block basis.

Summary SSD is a data storage device that uses integrated circuit assemblies as memory to store data persistently. SSDs do not employ any moving mechanical components, which distinguishes them from traditional magnetic disks such as hard disk drives (HDDs) or floppy disks SSD’s are created using DRAM & flash memory. SSD have fast speed and low power consumption as compared with HDD. Cost of SSD is little bit more than HDD’s.

Conclusion : As SSD is a new innovative technology which will provide high data transference, high data security. The most highlighting feature is power consumption which can be contributed by Intel third generation SSD .With the help of Intel 3-D Tri-Gate processors . Hence in the future the presence of cache memory can be avoided by using these Intel third generation SSD. The main motto of using Intel organization is to cut the energy use by 50% by implementation of these Solid State Drives.

Resources Used : http:/www.intel.com/go/SSD http:/www.physorg.com/news http:/www.storageview.com http:/www.ssd.org http:/www.Google.com

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