Physical storage capacity of flash drives. Find out what is useful to know.02/02/2015
For most users, storage capacity is the main criterion for choosing a flash drive.
When we buy a USB memory stick of a particular capacity, we expect it to have the same amount of disk space as the manufacturer declares. Why is it that a flash drive always turns out to have less storage capacity than expected when we connect it to a computer?
The information provided by the manufacturer is based on the size of the flash drive’s memory, which is not equivalent to that available to the user for storing data. One reason is that manufacturers of chipsets for all kinds of storage devices (flash drive, SD cards etc.) use
a decimal system to describe the amount of storage space, while a computer’s CPU does the same but using the binary system.
If we measure capacity the way manufacturers do, we find that:
1000 B = 1kB,
1000 kB = 1MB,
1000 MB = 1GB.
This means that an 8 GB storage device really does have 8 GB.
However, a computer uses a binary system to calculate the capacity:
1024 B = 1kB,
1024 kB = 1MB,
1024 MB = 1GB.
As a result, the 8 GB of declared memory capacity translates into 7.2 GB of free disk space, as seen by the computer.
What is more, flash drives come with pre-saved boot files, which are necessary for the devices to operate properly.
In order to verify how much storage space a flash drive offers, we can run specific software that can be downloaded from the Internet free of charge. It will also allow us to measure the device’s writing and reading speeds.
The approximate usable storage capacities for particular flash drives are given below (1 GB = 1,073,741,824 bytes):
57.6 GB (64 GB flash drive)
28.8 GB (32 GB flash drive)
14.4 GB (16 GB flash drive)
7.2 GB (8 GB flash drive)
3.6 GB (4 GB flash drive)
1.8 GB (2 GB flash drive).