Storage Capacity 101 to Post-Grad in a Flash

In this report from Quocirca, analyst Clive Longbottom explains why you don’t always get what you think you’re getting with flash storage.

Data is made up from bits of information – 8 bits to a byte (4 to a nibble, for those who care). Kilobytes, Megabytes, Gigabytes, Terabytes and Petabytes all used to be based on the ‘power of 2’ system, so 1kB was 1,024 bytes (2 to the power 10), but has now come in line with standard metric notation, and is now 1,000 bytes.

This immediately affects storage for anyone who was brought up on the power of 2 notation. As 1MB would be 1024 bytes squared (1,048,576 bytes), 1GB 1024 cubed, and 1TB 1024 to the power 4, we start to see how the quoted storage of a disk is less than many of us expect. It may only lead to a 1% error at the kilobyte level, but it’s getting close to 10% at the terabyte level; that is capacity that many think they are getting that they are not. To this end, the IEC has renamed old-style units as kibibytes (KiB), mebibytes (MiB) and gibibytes (GiB).

But, as with all-flash storage, you get to use much more of your available capacity than with a disk-based solution.