An SSD (Solid State Drive) is basically a flash storage device, which is the next generation equivalent of an HDD (Hard Disk Drive). Where they differ greatly is an HDD contains spinning magnetic platters which are read and written to by heads floating on a cushion of air along a series of guides known as 'actuator arms', while an SSD contains no moving parts, and instead of spinning platters uses a special type of memory known as NAND flash. The most important advantages of an SSD compared to an HDD are as below:
- The key advantage is that they are much faster than an HDD.
- An SSD contains no moving parts, so there is no mechanical wear.
- An SSD produces next to no heat at all.
- An SSD is silent, as it contains no mechanical parts.
- An SSD consumes much less power compared to an HDD.
- • Robustness. Drop an HDD onto the floor and the chances of it still working are remote. Drop an SSD, and unless you are very unlucky, the SSD will not be damaged and should continue to function normally.
- An SSD has very much faster access times compared to an HDD.
- An SSD has much greater data throughput than an HDD.
As we mentioned above an HDD has spinning magnetic platters to store the data, and that data is read or written by a series of read/write heads. Each platter has its own head, and the head is moved from the outside of the platter to inside of the platter by the slide actuator assembly. The head can only be in one place at any one time, and it takes time to move that head from one location to another. Even if it's only a 1mm away, it will still take a few milliseconds to move the head before reading or writing can recommence.
An SSD reads and writes its data from NAND flash, and it's not uncommon for the SSD controller to have eight channels to transfer data to and from the NAND. Also the time taken to access the data can be 100 times faster than it is on an HDD. So as well as being capable of 8 times the throughput, it can also access the data much faster than an HDD.
If we compare a few SATA 6Gbps SSDs with one of the fastest HDDs currently available, in a real world multitasking test, you will find the fastest SSD is very nearly 10 times faster than the HDD.
Now there are two types of SSD Solid state drives (SSDs) based on flash memory: MLC SSD and SLC SSD. Generally the SSDs can provide faster transfer speed, higher reliability, and lower power consumptions rather than HDDs
A. Based on Nand Flash
I. SLC or Single Level Cell, allows for the storage of one bit of information per NAND memory cell. SLC NAND offers relatively fast read and write capabilities, high endurance, and relatively simple error correction algorithms. SLC is typically the most expensive NAND technology. A SLC NAND Flash PE cycle is written as 100K times in its Datasheet while read is unlimited. SLC drives are more suited for enterprise and digital recording systems environments because of frequently write operations. II. MLC or Multi Level Cell, technology in general is less robust than SLC as there are two bits stored in each cell. If one cell is lost two bits will be lost. A MLC NAND Flash PE cycle is written between 3,000 to 5,000 times while read is unlimited. The drives are usually available in larger capacities and are usually cost-effective. MLC based SSDs are ideal storage devices for consumer and few write operation environments.
B. Based on Host Interface
I. SATA SSD: SATA SSDs are based on the industry standard SATA interface.
II. PCIe/ NVMe SSD: PCIe SSDs are based on the industry standard PCIe/ NVMe interface.
III. PATA 44PIN: PATA SSD based on the industry standard IDE interface
With regard to physically installing the drive, it's actually more or less similar to installing an HDD.
- If it's a laptop, you just replace the HDD with an SSD (assuming that the laptop has a 2.5 inch drive bay).
- If it's desktop PC with a 3.5 inch HDD, then all you need is a 3.5 inch to 2.5 inch converter bracket.
The electrical connections are the same as an SATA HDD, but there some things that you should be aware of before you use the SSD.
For technical reasons, that are incidental to this guide, the partition on an SSD needs to be aligned. This is to make sure that the NAND pages start at the correct offset. Failure to align the partition will result in lower performance and will induce higher wear on the NAND.
Windows Vista, Windows 7, and Windows 8 will align the partition correctly when you create the partition. Windows XP won't. So if you are using XP, then perhaps it's time to update.
For a new Windows 7 or 8 build.
Simply connect the SSD then enter the system BIOS and set the SATA transfer mode to AHCI. IDE mode is not recommended for an SSD, as IDE mode can't support NCQ (native command queuing).
Place your Windows 7/8 DVD in your burner and boot from the burner. When you get to the installation screen, select the advanced options, then click on create partition (selecting the SSD). The SSD will be initialized, and the partition will be automatically aligned when it's created.
For an existing build.
Connect the SSD to a spare SATA socket, start the system and when it boots to the desktop, right click on the "Computer Icon", and then select "Manage", followed by "Disk Management" from the menu. If the SSD is new it will need to be initialised and a popup should appear. When it does, select the MBR option. The SSD will then be initialised.
Once this is done the RAW partition should appear in the list. Right click on the SSD and select "create a simple partition". Select the default which would normally be NTFS, and make sure you select the quick format option (NEVER do a FULL FORMAT ON AN SSD).
Once this completes you are ready to install the operating system on the SSD, or use it as a storage drive, if that's what you prefer.
Basically this is down to the number of NAND chip packages on the SSD, and the density of these packages. Almost all modern SSDs have a controller that can use multiple channels to read and write to the NAND. NAND is rather slow on its own. SSDs get their speed from reading and writing to several NAND packages at the same time. The sweet spot will generally be SSDs with 8 channels addressing 16 NAND chip packages.
Again we must go back to MLC NAND basics, and the read, modify, NAND block write method. But if the SSD controller is smart and fast enough, why just do one of these processes at a time? In actual fact they don't. While the SSD is busy doing the write process on one block, it can also use another channel to do the read and modify. This is called interleaving, but unfortunately 16 NAND chip packages are required to get the best out of this method with an SSD controller which supports 8 channels to the NAND array.
This makes perfect sense on the larger capacity SSDs. For example for an SSD with 256GB of NAND, you can use 16GB NAND chip packages, and for a 512GB SSD you can use 32GB packages in order to get the magic 16 NAND chip packages. Unfortunately trying to maintain this 16 NAND chip packages on small capacity SSDs would be prohibitively expensive, and would result in small capacity SSDs being non competitive.
Things may change in the not too distant future. ONFI 3 NAND will soon be available, supporting speeds of up to 400MB/s per NAND die. So it is certainly possible that only 4 or 8 NAND chip packages are required to fully saturate the SATA 6Gbps system bus. If this should happen then smaller capacity SSDs, at least for sequential reading and writing could be every bit as fast as their larger counterparts.
The useful life of an SSD is governed by three key parameters: SSD NAND flash technology, capacity of the drive, and the application usage model. In general the following life cycle calculator can be used to figure how long the drive will last.
Life [years] = (Endurance [P/E cycles] * Capacity [physical, bytes] * Overprovisioning Factor) / (Write Speed [Bps] * Duty Cycle [cycles] * Write % * WAF) / (36 *24* 3,600)Parameters: Endurance, NAND P/E Cycle: 100K SLC, 30K eMLC, 3K MLC
Capacity: Usable capacity of the SSD
Over provisioning Factor: Over provision NAND percentage
Write Speed: Speed of write in Bytes per second
Duty Cycle: Usage duty cycle
Write %: percentage of writes during SSD usage
WAF: Controller Write Amplification factor
SSDs are best suited to applications that require the highest performance. Below are some typical applications:
- Industrial Automation environments are diverse yet share common requirements – with regard to small form-factor, high durability e. Implementations include: large production plants, industrial PCs, Industrial Measurement, factory automation/robotics, kiosks, ATMs, POS terminals, process control units and data loggers.
- Transportation/ In-Vehicle and applications are inherently subjected to extreme temperatures, shock and vibration, and high humidity. Implementations include: GPS / geo-location and navigation, rugged PCs, in-vehicle control, monitoring, and surveillance/security.
- Professional media companies range from high-performance HD video capture to broadcast video serving and digital signage applications. Some devices require heavy write performance (data capture) – others require high read performance (video serving). Implementations include: professional video capture/editing, TCMS, broadcast, ad terminals, Multifunctional Terminals indoor/outdoor multimedia signage, data recorders and etc.