SSD or not SSD – is that the question?
A solid-state drive, or SSD, is a data storage device that uses solid-state memory to store persistent data. A hard-disk drive, or HDD, is a non-volatile storage device that stores digitally encoded data on rapidly rotating platters with magnetic surfaces. So which is better? This article examines the pros and cons of each and argues that both will, and should, coexist.
HDDs were first introduced in 1956 and haven’t looked back. In comparison, SSD technology can be dated to the era of vacuum tube computers. However, back then, cheaper drum storage units phased it out. In the 70s and 80s it made a brief comeback being implemented in semiconductor memory for the early supercomputers of IBM, Amdahl and Cray, unfortunately history was to repeat itself and the prohibitively high price meant it was seldom selected. This year SSD has resurfaced, some would claim with a fire in its belly, as ‘a rapidly developing technology’ primarily appearing in laptops albeit still substantially more expensive per unit of capacity than hard drives.
There are five key areas to compare when evaluating and selecting SSD and/or HDD technologies so, let’s examine the evidence.
If Size Is Important:
HDDs win hands down on the capacity front with SSDs significantly lower at 512 gigabyte currently the largest drive you can buy. In comparison, you can get a 2.5” HDD with 1 terabyte and 3.5” with 2 terabytes.
The capacity issue is further impacted due to the low storage density of SSDs, hard disks can store more data per unit volume than DRAM or flash SSDs.
That said, it is still relatively early days and the SSD market isn’t resting on its laurels. Over the last 12 months, Intel has issued a number of statements announcing increasingly larger devices and is expected to continue to do so during 2010, and it won’t be the only player.
If Speed Is The Driving Factor:
This is where SSD’s take the chequered flag every time. They are significantly faster than HDD’s, in some cases up to 100 times faster, and therefore one obvious benefit is in improving the boot up process as it’s practically instantaneous, and as a result of the faster read and seek time faster application launch. In the case of a laptop, this could prolong the life of the battery as energy isn’t wasted in ‘spin-up’.
However, this speed isn’t replicated in ‘write time’ which is around 18 MB/s compared to over 50 MB/s for hard drives.
If Failure Isn’t An Option:
SSDs are considered ‘less fragile’ as the lack of moving parts almost eliminates the risk of “mechanical” failure resulting in the ability to endure extreme shock, high altitude, vibration and extremes of temperature – this could be a key consideration for the industrial market. Some even claim SSDs can be dropped without suffering data loss.
However, there is a downside. As a result of wear leveling and write combining, the performance of SSDs degrades with use. It is also thought that an abrupt power loss, magnetic fields and electric/static charges could have grater impact on an SSD compared to normal HDD’s. In the case of a crash, after an SSD fails it is nearly impossible to recover any of the data.
If Security Means Secure:
HDDs have a higher level of security and compatibility currently to SSDs which are vulnerable to physical hacking against both the flash memory and the chips that secure them. In addition, traditional data shredding software is ineffective due to the wear-levelling process SSDs use to prolong the life of the flash cells.
The use of encryption software for SSDs is one argument however this can cause compatibility issues as it often does not work in MAC, thin client or Linux environments.
Some external encrypted SATA drives, are platform independent and therefore offer the user a high level of flexibility and compatibility.
However, higher levels of security are an issue in today’s mobile world where users have all forms of sensitive electronic data within the public domain. Multi layer encryption and dual authentication can be achieved in the SATA environment due to a wider range of development and investment in this mature technology. Encryption levels in SSD are still in their infancy but seem to be catching up rapidly. No doubt the encryption area will be an important part when making a decision on SSD or SATA, right now SATA is winning in this specific arena but who is to know if that will be the case in 12-18 months time.
If Price Is Prudent?
As of mid-2008, SSDs are still more expensive per gigabyte than hard drives as an 1 terabyte disk drive can be purchased for under $100, in comparison to $3,300 for the 1TB Colossus SSD . Of course, smaller SSDs are available. One argument is that you’re not buying space – you’re buying performance, although you then have to question whether performance is really worth the extravagance.
While examining price, it is prudent to point out that currently there’s a considerable amount of disparity in the SSD market, especially in terms of the quality of the product, with some manufacturers pricing relatively low and others quite high with it often difficult to determine what the difference actually is to warrant the discount/inflation.
At a time when everyone is examining their budgets for cost savings, SSD is an expensive option but is that enough to condemn it to the pages of history again or will some of its other key functionality mean it’s third time lucky?
It’s Betamax vs VHS All Over Again
Confined to yesteryear, Betamax was a home videocassette released by Sony in the mid 70s. A year later, in 1976, VHS was launched by JVC and the battle for supremacy began. Those who supported Betamax lost out when the format became virtually obsolete a few years later. A far more recent battle saw Blu-Ray defeat HD DVD in July this year. However, it doesn’t have to end in submission and the MAC versus PC co-existence is testament to how two technologies can establish their own loyal community and happily co-exist. It is my opinion that the same will be true for SSD and HDD, both settling into a life long partnership.