The analogy of the difference between the two may be easy to understand. One of the simplest analogies used by the storage industry is that flash memory is like an egg and SSD drives are like an omelette. The omelet is made mostly of eggs, and the SSD drive is made mostly of flash memory. If someone asks you what you had for breakfast, it's understandable if you answer quoteggs quot, even if you did have an omelet.
Eggs can be used to make a lot of food besides making omelets. Similarly, there are many things one can do with flash memory besides make SSD drives.
What is flash memory?
Flash memory is a silicon chip-based storage medium that can be written or erased electrically. Other examples of storage media include mechanical hard drives, magnetic tapes, CDs, DVDs, Blu-rays, and even floppy disks and perforated cards.
Speed: Flash memory has a few unique features that make it particularly well suited for storing enterprise data. First, as the name implies, it can be accessed much faster than mechanical hard disks.
No moving parts: Unlike mechanical hard disks or tapes, flash memory can be used to make hard drives with no moving parts. In general, this makes it less likely to be interrupted or fail, especially when the storage facility is moved Distinguished from the latter, which is also very fast to access, but is erased every time the system is shut down.
Easy to rewrite: flash memory is easy to rewrite, making it useful for storing frequently changed data.
Besides SSD drives, flash memory can also be used for other products. For example, cell phones, laptops, digital cameras, camcorders, memory cards, USB flash drives, calculators, medical devices and even some digital toys use flash memory.
It's also worth noting that there are several different types of flash memory. The two most common types are NOR flash and NAND flash. The first of the two has also not been developed. It's fast to read but not fast to write, so it's most commonly used where you're writing code and reading a lot of data at once.NAND flash has faster write speeds than NOR flash and takes up significantly less space, which also makes it less expensive.Most of the flash memory used in SSDs is NAND flash.
The biggest drawback to flash memory is that it is currently quite expensive. But as technology advances, the cost will come down, making flash memory more cost-effective in enterprise environments. Some organizations Data centers are even opting to ditch mechanical drives altogether and go all SSD drives.
What is SSD storage?
An SSD is a storage device. Most SSD drives on the market today use flash memory as the storage medium. The relationship between flash memory and SSD drives is similar to the relationship between CDs and optical drives. The CD is the medium and the optical drive is the storage device. So you can think of flash memory as the medium and SSD drives as the storage device.
However, an SSD drive doesn't have to use flash memory as its storage medium. Its name is quotSolid State Drive quot, so any immovable type of storage can be counted as an SSD drive. In fact, historically, the earliest SSD drives did not use flash media. Future SSD drives may also use media other than flash.
Most SSD drives use the same form factor as HDD drives. This makes it easier for users to migrate from disk-based storage to solid-state storage. Organizations can buy individual drives with HDD drives installed or arrays of SSD drives. combinations of HDD and SSD drives are another popular option for arrays.
History of solid-state drives and flash memory
SSDs have a much longer history than flash. While some of them date back to the origins of SSDs in the 1950s, the first true SSDs were introduced in the 1970s.
The original SSD drives relied on a type of computer chip called erasable read-only memory.EAROM also appeared in some early video games, but the technology was never really widely used.
In the mid-to-late 1970s, some manufacturers began selling RAM-based SSD drives. Like flash memory, RAM was fast to access. But unlike flash, RAM is volatile, which means that everything stored in RAM is erased when the power is turned off. There are some obvious problems with power outages, so many early SSD drives had battery backup systems.
Storage manufacturers continued to improve and market RAM-based SSDs into the 2000s. During that time, they also experimented with other technologies that could be used to create SSD drives. In the early 1980s, Intel introduced a product called Bubble Memory, which attracted people and was integrated into some early personal computers, including the Apple II computer. However, when designers tried to expand the capacity of Bubble Memory, they ran into technical problems, so Intel quickly abandoned the product and the technology.
Almost simultaneously, bubble memory seemed to be the hottest new thing, and a Toshiba employee named Fujio Jieoka came up with the idea of flash memory. He presented his invention at a 1987 storage industry conference, and in the late 1980s the first flash memory products hit the market.
Flash-based SSDs were introduced in the early 1990s, but were very expensive.SunDisk sold a flash-based 20MB SSD drive in 1991 for $1,000. Its price equaled the current $1,900, or about $95,000 per GB.
For most applications, the high price has prevented flash from being widely used, and its access speeds aren't as fast as memory, both of which are specific to the storage technology. However, flash's nonvolatility makes it attractive enough that researchers continue to develop it even as they sell RAM SSDs.
By the 2000s, SSD drives were really starting to be used, and flash memory was gradually becoming more popular than RAM. Then in the 2010s, the price of flash memory began to drop to the point where companies could replace older storage technologies with flash-based SSD drives.
The future of SSDs
As mentioned above, almost all SSD drives on the market are based on flash technology, which is why people sometimes think that quotflash quot and quotSSD drive quot are the same word. However, that's not always the case.
Storage manufacturers are continuing to develop new alternatives to flash memory. One of the more promising is 3D Xpoint, which is backed by Intel Corp. and Micron Inc. and sold under the Optane and QuantX brands. Like flash memory, 3D XPoint is non-volatile. It is said to offer 1,000 times lower latency and higher indexing than NAND flash.
But, like early flash memory, 3D XPoint is still expensive and few users are currently in the market.
Other potential flash alternatives include spin-transfer moment random-access memory, resistive RAM and phase-change memory. So far, other storage products, including 3D XPoint, have yet to become mainstream in the storage market. Only over time will we know which products will be the next flash memory or if they fit the bubble memory approach.
Most SSD drives will continue to be based on flash technology for the foreseeable future. That could mean that much of the storage industry will continue to use the terms quotflash quot and quotSSD quot interchangeably.
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