The Disk Is the Bottleneck

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This out-of-sight, out-of-mind attitude toward disks, however, may be misguided. Consider the mechanics of disks with regard to one very important factor — system performance. A 2-GHz CPU means 2 billion operations per second. RAM operates at 20 to 30 million operations per second, sometimes faster. Now factor in the hard disk. Good ones take about 5 milliseconds to access data — that is only 200 operations per second (Exhibit 1). Some can go faster, but not much faster. The point is that poor disk maintenance and disk management can mean that big powerful systems are held up badly by the sluggardly nature of the hard disk. So, it makes sense to know about disks and to be able to take action to avoid disks becoming a bigger bottleneck than they already are.

Exhibit 1: Relative Speed of Components

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