The hard drive capacity in Windows (for the Warp Drives) or the NAS User Interface reports less than indicated on the drive label.

Document Details

Article ID
T4303-1330

Last Review
July 23, 2007

Products
Wired NAS
Server Appliance
Web Server
Warp Drive 2.5"
Warp Drive 3.5"

Firmware Versions
1.37 +

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Different applications report hard drive capacity differently or file sizes differently. For example, you may have a 120GB hard drive and Windows may report it as 110GB.

 

Hard drive manufacturers market drives in terms of decimal (base 10) capacity. In decimal notation, one megabyte (MB) is equal to 1,000,000 bytes, and one Gigabyte (GB) is equal to 1,000,000,000 bytes.

Programs such as FDISK, system BIOS, and Windows use the binary (base 2) numbering system. In the binary numbering system, one megabyte is equal to 1,048,576 bytes, and one gigabyte is equal to 1,073,741,824 bytes.

Simply put, decimal and binary translates to the same amount of storage capacity. Lets say you wanted to measure the distance from point A to point B. The distance from A to B is one kilometer or .621 miles. It is the same distance, but it is reported differently due to the measurement.

Capacity Calculation Formula

Decimal capacity / 1,048,576 = Binary MB capacity

Example:
A 40 GB hard drive is approximately 40,000,000,000 bytes (40 x 1,000,000,000).

40,000,000,000 / 1,048,576 = 38,162 megabytes

In the table below are examples of approximate numbers that the drive may report.

Decimal Binary MB Windows Output
20 GB 19,073 MB 18.6 GB
40 GB 38,610 MB 37.3 GB
60 GB 57,220 MB 55.8 GB
80 GB 76,293 MB 74.5 GB
120 GB 114,440 MB 111.7 GB
160 GB 152,587 MB 149 GB
 

 

If you are trying to determine the total and free space on the Wired NAS, Server Appliance, or Web Server, please use the NAS User Interface instead of Windows.

   
TRITTON Technologies, Inc.