Solid State Disks


It’s about time we have a little chat about this subject. Maybe you noticed that this type of hard drive is becoming more and more popular these days. Or in case you completely missed it, a solid state disk is “the hard drive of tomorrow”. Consider this to be the large version of the SD card, that is in your phone or digital camera, for your computer.

One of the many differences comparing to a normal hard drive is that is does not contain any moving parts. A solid state disk is a flash drive which is electrical, capable of storing data even when there is no current running through it. The process of saving a reading data is fairly simple. The same as reading a CD of DVD for example, a cell can either be 0 or 1. You know, binary stuff ;-).

The reading and writing is controlled by the ehm.. controller. This is an component which is programmed just for these tasks. It is this small component  that also have a great impact on the performance of the SSD.
In the world of SSD there are 2 types of disks. They are called MLC and SLC. Multi Level Cell and Single level Cell.

There is no physical difference between these two types of disks, the only thing different is the type of controller used. In the SLC type the controller can make a distinction between 2 voltage values, high and low. On and Off. 1 and 0. Whatever you like to call it.  In MLC drives however, it can make a distinction between 4 of them. And no I’m not going to write down all the combo’s, you get the point. The big difference between the two is that in a SLC drive’s cell 1 bit can be stored. In a MLC drive’s 2. This doesn’t seem like a lot, but in the end this makes quite a bit of a difference.
This however has a disadvantage, since the MLC controller needs to be able to identify 4 types of values, the reading will be somewhat slower than with the SLC drive.

Now this all sounds rather nice, it does to me at least. But there are a few things you should still know before you run of to your local computer store to get a few dozen of these drives. SSD are still rather pricy compared to the ‘normal’ hard drives. And it’s still not quite certain how long these drives actually last. There are manufacturers that give a 5 year guarantee but let’s face it. This is not very sure ;-).

But by all means, don’t let this stop you, it seems to be the future, so you’ll be stuck with it not matter what :D.

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