What is it?

Standing for solid state drive it's an alternative to the hard disk drives used for storage and is a favourite in the low cost netbooks that are seen around today from the likes of Asus.

SSDs traditionally have the type of onboard technology used by your computer's RAM or USB Flash drives rather than storing data on hard disk drive (HDD) platters.

This makes them faster in both writing and reading data, as compared to the HDD. There are also many other factors involved relating to additional benefits they have over a normal hard disk drive, more of which we’ll go into later.

It's common to see SSDs in notebooks and more increasingly so in laptops too. These often fall under the normal drive size capacities of the 2.5-inch and 1.8-inch form factors, which are associated with standard HDD sizes for storage within these types of computers.

Although it appears SSDs are a recent addition to the IT world, they have been around for some time in some form or another. They even date as far back to the early home computing days of the Amigas and Ataris in the 1980s, where hard drives were expensive and these were then commonly referred to as RAM drives. There is a history of them dating back even further than that, with the likes of mission critical applications used by the military – in which they are still very popular today.

What are the variations of the technology?

There are a few ways to deliver SSDs. These range from being embedded in the device down to the type of interface used from the likes of PATA (parallel ATA or PSSD) to SATA-II, all which go on to mimic to a degree a hard disk drive in their operation.

Inside the SSD itself there are a couple of variants surrounding the memory used making up its storage abilities. These fall into two categories, known as SLC and MLC – standing for single level cell and multi level cell.

The first allows for faster transfer of the data onboard, where it's a tad more expensive than the other type of memory.

The second version, being that of MLC offers much higher levels of storage as compared to the other, but is slower in terms of transferring the data from the chips to the computer.

It's becoming more and more common these days to see both of these types of memory used in an SSD, as both have their strengths and together they can capitalise on their distinct technologies.

SSDs are already fast in transferring data by default, no matter what type of memory is used in their manufacturing it's just that SLCs are that little bit faster over MLC chips.

Why should I care?

There are several key benefits SSDs have over HDDs, most of which relate to the difference in architecture they have over platter-based storage as compared to NAND-based storage.

These can be mostly attributed to a number of reasons ranging from performance, low power consummation and durability.

SSDs have no moving parts, unlike a hard disk drive. This means there's really no wear and tear as associated with its alternative, creating on the whole a longer life for the drive.

There are some stats worked out by Samsung, where the average MTBF – mean time between failures (the expected running time before the drive could possibly develop a fault) – of a 2.5-inch HDD is less than 700,000 hours.

The same standard for an SLC and an MLC based SSDs are more than 2 million, and 1 million hours respectively. This clearly highlights their benefits being much greater than a normal hard drive, in terms of just how long it's expected to be up and running problem free.

As there are no spinning disks or heads needed to search for the data, the performance is greatly increased with a boot time that's been said to be 40% faster than an HDD. On top of that, there's the increased data transfer in read and write times to the SSD.

Just to put this in context, a 2.5-inch hard disk drive can have a 59MB/s read time where an SLC can have a 100MB/s read time. Once again, this just further highlights the benefits very clearly from one to the other.

Netbooks, which are a popular choice in mobile computing today can benefit from SSDs for extended battery life. It's been noted by Samsung that their SSDs pull just 0.4W whilst at their most active period, with a 2.5-inch HDD pulling in 2.1W – over five times that of the other.

What's a good example in practice?

There are various types of capacities around today, most still relate to the lower end of the spectrum rather than the mighty sizes seen in the larger terabyte drives.

SSDs can be seen in netbooks ranging in capacity from 8GB upwards. SanDisk do have ranges reaching as high as 240GB, seen in their latest G3 family of products which also include 60 and 120GB variants.

Other well known companies such as OCZ Technology have produced 250GB SSDs, whilst Samsung has also been said to be turning out a 256GB model.

The lower capacity drives can be seen in many netbooks around today, with more planned on the horizon. These are all present and are included for the benefits we mentioned in the last section.

Manufactures such as Buffalo are also offering SSDs in the form of larger portable external storage, and are also looking towards NAS (Network Attached Storage) for trouble and risk free backups.

Is there a competing technology that I should be aware of?

The alternative is of course, the hard disk drive. On the whole the HDD is a lot cheaper per megabyte than the SSD, by some considerable factor too.

Some netbook manufacturers have in the past balanced out the SSD Vs HDD price point by offering various SKUs whilst each have their own merits over one another. These fall under the categories of larger hard drives with Linux installed and a larger battery to accommodate the power drain, to SSDs with Windows XP and a smaller battery onboard.

What is in store for the future?

On the not too distant horizon is increased storage, faster access to data and cheaper ways of both making and offering SSDs to the users or companies.

There have been announcements of late by Toshiba and also SanDisk, who are two of the key players in this field offering up news of breakthroughs inside this arena.

The first made public details of a prototype of FeRAM based chips, which could very well drive the next generation of SSDs. These types of chips can offer read and writing speeds of 1.6GB per second, whilst delivering the capacity of 128MB per chip.

This trumps their own current ceiling 200 megabit data transfer speeds, with 32 megabytes of possible storage. With this new technology being almost eight times that of what's around today.

SanDisk at CES unveiled their next generation of SSDs, which operate at the equivalent of a 40,000 RPM hard disk drive, based on the MLC type of chips – where the common HDD runs in at around 7200 RPM.

Asus has a new notebook that was also launched at CES this year known as the S121, this is said to have a 512GB SSD onboard when it arrives. Meaning it will have the largest solid state disk possible at the time of being on sale, later on this year.