More information about Seagate 3.5" SATA hard drives

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Serial ATA 3 hard disk drives for computers

A hard disk drives stores computer information.

Hard drive space is given in Gigabyte or Terabytes.

The size of a hard drive displayed in an operating system, such as Linux or Microsoft Windows, will not be the same as the "rated" hard drive space,and it will always be less. The reason is the way data on a drive is defined compared to the way computers sees the same amount of data.

For hard drives, the sizes are as follows:

• 1 MB = 1,000,000 bytes
• 1 GB = 1,000,000,000 bytes
• 1 TB = 1,000,000,000,000 bytes

But for a computer, this is not the case since it works using binary digits (everything is either a zero or one, and as a result, there are only 2 digits) and not in decimals like humans (10 digits):

• 1 kilobyte = 2^10  = 1,024 bytes
• 1 megabyte = 2^20  = 1,048,576 bytes
• 1 gigabyte = 2^30  = 1,073,741,824 bytes

As an example, if we take 1 Gigabyte hard drive, the computer will see 73,741,824 bytes "less", displaying available space as 0.931 Gigabytes! This is nevertheless still a 1GB drive.

SATA revision 3.0 (SATA 6 Gbit/s)

Serial ATA International Organization presented the draft specification of SATA 6 Gbit/s physical layer in July 2008. It provides peak throughput of about 600 MB/s (Megabytes per second) including the protocol overhead (10b/8b coding with 8 bits to one byte).
 
In general, the enhancements are aimed at improving quality of service for video streaming and high-priority interrupts. In addition, the standard continues to support distances up to one meter.
 
The later standard is backwards compatible with SATA 2 (3 Gbit/s).