Sunday, August 26, 2012

Solid State Drives for a “Solid” Computing Experience

It does not take much effort to hear an all too common occurrence in hospitals that “the computers here are so slow.” But why are they slow? Every upgrade cycle means lots of new machines – more expensive machines with more RAM, faster processors and bigger hard drives. That should be enough, right? Or so, many people think, because there is always one component that seems to be neglected - the hard drive. And there is one technology that still does not receive enough attention in the medical realm - the solid state drive (otherwise known as an “SSD” and sometimes referred to as “flash memory” – although it is very different than a typical USB flash drive). We feel that not enough people realize that their computers are “held back” by their hard drives. Because traditional hard disk drives (HDD) contain a spinning disk, they are relatively slow at transferring data. Even with hard drives advertising data transfer at 100 megabytes per second (MB/s), the real-world performance, which involves writing lots of small files (also known as the ‘4 kilobyte (KB) random read/write time’) is notoriously slow – less than 1 MB/s! Furthermore, file fragmentation slows PCs with HDDs considerably; PCs become virtually useless during the defragmentation process that needs to be performed periodically. On the contrary, SSDs’ performance is not impacted by fragmentation, therefore there is no need to perform defragmentation. Various review sites such as www.anandtech.com have compared the performance of systems running on computers with HDDs to similarly-configured models with SSDs, like this example using PCMark Vantage. The results are staggering, considering that the PCs configuration and the utilized software in this comparison were identical – the only difference being the hard disk drive swapped for a solid state drive. Aside from benchmark tests, what about real world day-to-day performance? From our exprience, it is much faster and smoother working with an SSD, which contains only memory chips and no moving parts. Have you ever waited for minutes for your computer to reboot? That time can be less than 15 seconds, or perhaps faster than Usain Bolt’s 100-meter dash in the 2012 Olympics. Does Microsoft Word, Final Cut Pro or Adobe Photoshop take too long to load? Application load times are shorter when using an SSD (as in this report with Adobe Photoshop), and whether you are using Microsoft Windows, Mac OS X or Linux, the overall boost in operating system performance becomes immediately apparent, particularly when multitasking. Furthermore, many notebooks now feature “instant resume,” allowing a computer to wake up immediately from sleep. This is not a feature restricted just to the new ThinkPads or MacBooks, but is also possible with many notebooks or even desktops – both new and old – when using an SSD, since the SSDs do not need to “spin up” like HDDs to begin reading data. The choice of operating system also affects the time required for systems to resume from sleep; for instance, Windows 7 on a notebook generally allows it to resume more quickly than Windows XP, but there are other hardware and software variables that can affect this. Of note, there are several arguments against the usefulness of SSDs in place of hard disk drives; one being that “not all SSDs are created equal”. As stated earlier, an important performance determinant is not the advertised sequential maximum read and write speeds, but rather, the random input and output operations per second (IOPS), particularly for small files. Solid state disks with slow random read/write speeds may perform no better (or in some cases, worse than) traditional hard drives. This comparison demonstrates an example of the wide spectrum of performance between various SSD models. Furthermore, long term reliability of SSDs may vary dramatically between manufacturers; while Intel, Crucial Memory and Samsung have very low reported failure rates, users have reported higher failure rates with select models from other companies. The most notable disadvantage of SSDs is increased cost-to-space ratio, particularly when used as server storage. Given the vast amount of healthcare data (and in particular for pathology, large images and virtual slide files), SSDs might still not be economically feasible for large-scale storage on a tight budget. However, the market is changing, and the price gap between SSDs and HDDs is narrowing. Five years ago, a paltry 32 GB SSD would cost over $200, whereas one could buy over a terabyte of hard drive space for that amount. Currently, for consumers, a 256 GB version of Samsung’s highly-praised 830 series SSD can be had for under $200. Pair this with a $400 notebook, and one could have a machine with markedly faster day-to-day performance than a $1,200 machine with twice as much RAM and a beefier processor. Moreover, SSDs are becoming much cheaper than, say, buying a new computer or tablet. And there are additional benefits that may make them more cost effective in the long run, such as lower energy usage, greater durability due to the lack of moving parts, and lower heat dissipation (important for server storage). In healthcare, the decision to use older hardware with SSD technology during the next upgrade cycle has probably never been considered. But, given how well technology from last year can perform with current generation SSDs, such a decision may become crucial in saving both time and money. Other options include using an SSD for the operating system and programs, coupled with a separate hard disk drive for data, to obtain “the best of both worlds” of speed and storage space. Are you reporting the word “slow” too many times to your PC support team? If so, then perhaps now is the time for another paradigm shift in healthcare IT, to understand the benefits that SSD technology can provide in a field already fraught with time constraints. As prices continue to drop, we hope that this technology will be supported by future healthcare professionals. By Milon Amin & Ioan Cucoranu

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