The mystery of the missing gigabytes will continue to baffle computer users until hard drive makers get in sync with the rest of the computer world. You’re not missing any gigabytes—it’s just a mix-up in units of measurement.
Disk capacity is measured using decimal kilobytes, megabytes, and gigabytes. In decimal units, 1KB = 1,000 bytes, 1MB = 1,000,000 bytes, and 1GB = 1,000,000,000 bytes. But for file sizes, memory, and just about everything else, we use binary kilobytes, megabytes, and gigabytes. In binary units 1KB = 1,024 bytes, 1MB = 1,048,576 bytes, and 1GB = 1,073,741,824 bytes. Looking at it another way, the decimal values are 103, 106, and 109 bytes, whereas the binary values are 210, 220, and 230 bytes.
To convert your disk’s 160 decimal GB to the units used by the rest of Windows, you have to divide by 1.073741824. The result is about 149GB—close enough to what you calculated. Sorry, there’s no missing 10GB for you to recover!
