Assured Systems Discusses the Advantages & Disadvantages of HDD v SSD

In computer history, hard disk drives (HDDs) have been around since the dawn of time.  In the 1950s IBM developed hard drives the size of a small car for super computers used by the US government (and some industrial customers) offering, wait for it, 3.75MB of storage space.  Developments continued and by the 80s PC hard drives started to be standardised into the 3.5" and 2.5" formats we see today.  Drive interfaces have also changed over the years, but still perform the same task of connecting the drive to the computer and allowing data transfer to ever increasing capacities; at the time of writing 3.5" drives max out at 4TB and 2.5" at 2TB.

One of IBM's First HDDs Back in the 1950s

If the HDD is the old man, the Solid State Drive (SSD) is the new kid on the block.  There have been experiments with solid state systems over the years, but nothing which was able to knock the trusty HDD off it's perch.  Until now, perhaps.  Standard HDDs contain multiple disks called platters, which are covered in a magnetic coating and then rotated at high speed. Drive heads then move across the platters, changing the magnetisation of the material beneath to record data, or reading its state to return the stored information.  SSD technology uses flash memory chips to store data, a much simpler design with no moving parts. Both solutions perform the same tasks; storing your OS, booting your system, storing and manipulating applications and files.

An SSD & Traditional Spinning HDD

As we've identified both HDDs and SSDs are essentially offering us the same functionality, we can now consider the advantages and disadvantages with both technologies.

Price
This has been one of the main reasons holding SSDs back from the mass market.  We've been using flash storage in embedded systems for many years; Disk On Chip, Disk On Module, and Compact Flash are all examples of flash storage used to improve the robustness of systems in harsh environments - but these disks were traditionally very small in terms of capacity, and normally more expensive than an HDD twenty times its size.  This is still true of today's market pricing; however, we are now getting to a stage where a reasonable size SSD (let's say 32GB+) is available for the same price as the lowest capacity HDD. Often these capacities are fine for industrial/embedded customers as they don't need Terrabytes of data storage.  So price isn't such an issue these days, depending on your application of course.

Speed
This is the SSDs pièce de résistance.  A machine with an SSD will boot in seconds, a traditional drive requires time to reach operating speed.  Also, over time an HDD can become slower due to factor such as fragmentation.  An SSD doesn't suffer these problems, and can access data no matter where it's stored in lightening fast time.  SSDs are inherently faster by design, and will access applications and files much quicker, meaning systems are more effective and reliable at performing their duties.

OCZ's Marketing Label Supplied with SSDs

Power Consumption
SSDs don't have motors or drive heads to move around the disc, thus power consumption is significantly less for an SSD versus an HDD.  This is an important factor for embedded systems, as less power means less heat; we can also consider battery operated systems, less power means a more efficient use of batteries.

Durability
With no moving parts, naturally SSDs are very robust when compared to traditional HDD.  This is one of the major benefits for using SSDs in embedded and industrial computer systems.  Harsh environments can mean systems are subjected to shock, vibration and rough treatment from operators.  Whilst HDD technology has improved drastically over the years, systems in 24/7 use benefit hugely from the use of SSD technology.  As far as longevity is concerned, it is true that SSDs wear out over time due to flash cells having a limited number of write cycles; however, with TRIM technology being built into the SSD, optimising read/write cycles, the system's MTBF figures are normally more than the likely life of the system itself.  There are some applications where we need to consider requirements carefully - high speed data acquisition, for example, may be writing many times a second, causing problems for the SSD much sooner than designed for.

Flash Chips Used in SSDs Mean No Moving Parts 

Conclusion
I think our discussion is fairly conclusive that the features of SSDs are very attractive to customers in the industrial/embedded computer space, and whilst there are still factors to consider, it's definitely now something worth considering when specifying a system for your next project.  Here at Assured Systems, we're building 75% of our systems with SSDs as standard, offering an HDD as an option to customers who need higher capacities, or have applications which demand a lot of write cycles.  Our experienced technical sales team can discuss your application in-depth and decide on the best solution for you, at a price point to meet your budget.

If you would like to discuss your project or application in more detail please contact technical sales on 01785 87 90 50 or email us at sales@assured-systems.co.uk.  For more information on Assured Systems please visit our website at www.assured-systems.co.uk.