Dabs technical glossary: The SSD edition

In an effort to break down barriers and make technology more open to everyone, me and the rest of the guys here at Dabs felt it may be useful to begin a regular feature which lays bare some of the frequently used technical words and terms,  that could be off putting to the uninitiated among us.

These will be relatively short posts but, I for one, really hope it means that a few more people we feel able to confidently handle the technology and devices that we’re all such fans of using.

This particular post will be especially relevant for a forthcoming post looking at SSDs and so will focus on three terms NAND flash memory, Write Amplification and SATA support.

Crucial 256GB Solid State Drive

NAND flash memory

NAND flash memory is a type of non-volatile (i.e. stable whilst still allowing the content to be accessed easily), digital storage technology that does not require a power source to retain data. There are two types of flash memory, NAND and NOR. The names refer to the type of logic gate (the fundamental building block of a digital circuit ) used in each memory cell.

Write Amplification

Write Amplification, is an undesirable occurrence associated with Flash memory and SSDs.  Flash memory must be erased before it can be rewritten, the process to perform these operations results in moving (or rewriting) user data more than once.  This multiplying effect increases the number of writes required over the life of the SSD which shortens the time it can reliably operate.  The increased writes also consume the bandwidth (i.e. the amount of data which can be transfer from one device to another component meaning the bigger the bandwidth the better) to the Flash drives memory, which mainly reduces random write performance to the SSD. Write amplification is typically measured by the ratio of writes coming from the host system (usually this would be your printer, web or databases) and the writes going to the Flash memory.  This might sound a little bit confusing but the best way to think about it is that the lower the number for write amplification, the better.  An example can be that until 2009, it used to be assumed that write amplification could not drop below one, but that year, a small but very talented company called SandForce made the claim they had a write amplification of 0.5.  However many different factors will affect the write amplification of an SSD; some can be controlled by the user and some are a direct result of the data written to the drive and the usage of data of the SSD.

SATA support

This stands for a Serial ATA, which is a standard type of cable, that is long, thin, and has 7-pins inside of the cable.  It is mainly used for connections to storage devices in a PC like optical drives, and hard drives to the motherboard.  The term SATA generally refers to the types of cables and connections that follow this standard.

So that a quick blast of information.  I sincerely hope that this will be useful and I would really appreciate any feedback on this post.

Let me know what you think and especially get in contact if there is a technical term or phrase you would like covered.

What is the geek jargon that you could never quite get your head around?

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