Flash storage is any type of data repository or storage system that uses flash memory. Flash memory is ubiquitous in small computing devices and becoming more common for larger applications. The size and complexity of flash-based systems varies for storage in wearable computing devices, embedded systems, smartphones, portable USB drives and more, all the way up to enterprise-class all-flash arrays. Flash is packaged in a variety of formats for different storage purposes. Flash storage uses and benefits: Flash memory has become more widely-used than the mechanical hard drive, even though it has not replaced it as the prevalent main storage in desktops. In notebooks, however, flash storage offers the additional boon of being more resistant to the high-g (gravitational acceleration) bumps and drops the devices often receive in their mobile lives. This rugged nature allows the drives to maintain function through these events, which saves data. Flash is more prevalent in notebooks than desktops, and smartphones and MP3 players have pretty much abandoned the mechanical hard drive altogether. Flash easily beats it for both compactness and power consumption. Flash also remains the standard form of storage in digital cameras, tablets and digital camcorders. Photolithographic shrinks continue to enable increase capacity, which makes flash suitable for increasingly miniaturized applications. How does flash storage work? Flash storage’s memory is actually a form of EEPROM (electrically-erasable programmable read-only memory). Unlike standard EEPROM, however, flash is a non-volatile memory type. This means that it does not require power to maintain stored data integrity, so a system can be turned off – or lose power – without losing data. Flash also erases whole blocks of data at a time rather than on a bit-by-bit level as conventional EEPROM does and so does not require complete erasure for a rewrite. Flash is solid state storage, storing data using electricity in surface-mounted chips on a printed circuit board (PCB). There are no moving mechanical parts involved, which reduces power consumption. A typical SATA flash drive consumes 50 percent or less the power required by mechanical drives and may be capable of sequential read speeds more than 500MB/s in consumer drives – faster than even the fastest enterprise-class mechanical hard drives. That is only a part of the picture, because access times are where flash really shines. Operating more like RAM than ROM, flash drives have no mechanical limitation for file access, which enables nanosecond seek times rather than the milliseconds required by mechanical hard drives – several orders of magnitude less latency. Most flash storage systems are composed of a memory chip and an access flash controller. The memory chip is used to store data; the controller manages access to the storage space on the memory unit. The flash controller is often multi-channel, working with a RAM cache that uses only 10 percent of the total drive capacity. The cache buffers the data going to and from a number of chips. Buffering enhances speed by reading and writing to the chips in parallel. Flash storage formats: NOR offers memory addressing on a byte scale, enabling true random access, along with good read speeds. It was this addressability that interested Intel in NOR, which the company often uses for its extensible firmware interface (EFI). NOR is more expensive per gigabyte (GB) than NAND because of its larger individual cell size. NOR also has slower write and erase times and is less durable than NAND when it comes to repeat reads, writes and especially erasures, where quantum tunneling of electrons is used to pierce the dielectric insulating material of the cell wall, which degrades the material over time. These characteristics make it a great replacement for EEPROM- or ROM-based firmware BIOS and EFI chips where the addressability and read speed is a boon while the rewrite durability is less of a concern. An OS, file storage or back up drive, on the other hand, might be more liable to expose the limitations of NOR in the resulting dead drives. NAND offers greater write speeds and durability along with lower cost per GB. The lower cost is partially a result of the NAND memory cell’s gate construction which is thinner, saving die space and reducing the overall size of a chip per GB. NAND can come in single-level cell (SLC) and multi –level cell (MLC) forms, which include enterprise MLC (eMLC), TLC. SLC stores a single bit of information per cell. SLC generally offers greater speeds, especially when it comes to writes, greater longevity and fewer bit errors. MLC provides storage capacity for more data, as its cell is capable of more levels of charge (or states), which allow it to store multiple bits of storage per cell. First generation MLC doubles capacity over SLC, TLC provides a third bit. The extra levels of charge along with smarter flash controllers and firmware can allow for bit error correction as well. Samsung especially has been hard at work trying to improve MLC forms of NAND flash and has brought flash into the terabyte range and created higher speed TLC