Supplementary Reading

Date: 2015-10-07; view: 410.

Answer the following questions.

1 When is it necessary to use a storage device?

2 What 3 categories are storage devices divided into?

3 What storage devices are referred to magnetic ones?

4 What optical storage devices do you know?

5 What can disk damage be caused by?

6 What factors have to be taken into account when comparing storage devices?

In electronics, a multi-level cell (MLC) is a memory element capable of storing more than a single bit of information.
MLC NAND flash is a flash memory technology using multiple levels per cell to allow more bits to be stored as opposed to SLC NAND flash technologies, which uses a single level per cell. Currently, most MLC NAND stores four states per cell, so the four states yield two bits of information per cell. This reduces the amount of margin separating the states and results in the possibility of more errors. Multi-level cells which are designed for low error rates are sometimes called enterprise MLC (eMLC).

Flash memory stores data in individual memory cells, which are made of floating-gate transistors. Traditionally, one bit of data was stored in each cell in so-called single-level cells, or SLC flash memory. SLC memory has the advantage of faster write speeds, lower power consumption and higher cell endurance. However, because it stores less data per cell, it costs more per megabyte of storage to manufacture. Due to faster transfer speeds and longer life, SLC flash technology is used in high-performance memory cards.