Terabyte
A terabyte is a unit of measurement in computers of one million million (American trillion) bytes. The symbol for terabyte is TB.Because of irregularities in definition and usage of the kilobyte, the exact number in common practice could be any one of the following:
- 1,000,000,000,000 bytes - or 10 12. This definition is used in most contexts relating to disk storage, networking, or other hardware.
- 1,099,511,627,776 bytes - 10244, or 240. This is 1024 times a gigabyte (a binary gigabyte). This is the definition most often used in computer science and computer programming; most software uses this definition.
A typical video store contains about 8 terabytes of video. The books in the largest library in the world, the U.S. Library of Congress, contain about 20 terabytes of text.
Personal computers containing a terabyte or more of storage space have recently become possible using combinations of high-capacity consumer hard drives. As drives now (2004) exceed 300 gigabytes in size, terabyte capacities can be reached using as few as 3 or 4 hard disks in a RAID (redundant array of independant disks) or JBOD (just a bunch of disks) or (just a bunch of drives) configuration, at a street cost of as little as 650 $USD. ( source: www.pricewatch.com)
A petabyte is 1024 terabytes.
To clarify the distinction between decimal and binary prefixes, the International Electrotechnical Commission (IEC), a standards body, in 1998 defined new prefixes by combining the International System of Units SI prefix with the word "binary" (see Binary prefix). Thus meaning (2) is called by the IEC a tebibyte (Tib), and meaning (1) is called by the IEC a terabyte. This naming convention has not, as of 2004, been widely adopted.
The prefix tera- comes from the Greek teras, meaning 'monster'.