In computer technology, transfers per second and its more common secondary terms gigatransfers per second (abbreviated as GT/s) and megatransfers per second (MT/s) are informal language that refer to the number of operations transferring data that occur in each second in some given data-transfer channel. It is also known as

sample rate In signal processing, sampling is the reduction of a continuous-time signal to a discrete-time signal. A common example is the conversion of a sound wave to a sequence of "samples". A sample is a value of the signal at a point in time and/or ...

, i.e. the number of data samples captured per second, each sample normally occurring at the clock edge. The terms are neutral with respect to the method of physically accomplishing each such data-transfer operation; nevertheless, they are most commonly used in the context of transmission of digital data. is 10⁶ or one million transfers per second; similarly, means 10⁹, or equivalently in the US/ short scale, one

billion Billion is a word for a large number, and it has two distinct definitions: * 1,000,000,000, i.e. one thousand million, or (ten to the ninth power), as defined on the short scale. This is now the most common sense of the word in all varieties of ...

transfers per second.

Units

These terms alone do not specify the

bit rate In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction ...

at which binary data is being transferred because they do not specify the number of bits transferred in each transfer operation (known as the channel width or

word length In computing, a word is any processor design's natural unit of data. A word is a fixed-sized datum handled as a unit by the instruction set or the hardware of the processor. The number of bits or digits in a word (the ''word size'', ''word wid ...

). In order to calculate the data transmission rate, one must multiply the transfer rate by the information channel width. For example, a data bus eight-bytes wide (64 bits) by definition transfers eight bytes in each transfer operation; at a transfer rate of , the data rate would be 8 billion bytes per second, i.e. , or approximately 7.45 GiB/s. The

for this example is (8 × 8 billion bits per second). The formula for a data transfer rate is: ''Channel width (bits/transfer) × transfers/second = bits/second''. Expanding the width of a channel, for example that between a CPU and a northbridge, increases data

throughput Network throughput (or just throughput, when in context) refers to the rate of message delivery over a communication channel in a communication network, such as Ethernet or packet radio. The data that these messages contain may be delivered ov ...

without requiring an increase in the channel's operating frequency (measured in transfers per second). This is analogous to increasing throughput by increasing bandwidth but leaving latency unchanged. The units usually refer to the "effective" number of transfers, or transfers perceived from "outside" of a system or component, as opposed to the internal speed or rate of the clock of the system. One example is a computer bus running at

double data rate In computing, double data rate (DDR) describes a computer bus that transfers data on both the rising and falling edges of the clock signal and hence doubles the memory bandwidth by transferring data twice per clock cycle. This is also known a ...

where data is transferred on both the rising and falling edge of the clock signal. If its internal clock runs at 100 MHz, then the effective rate is , because there are 100 million rising edges per second and 100 million falling edges per second of a clock signal running at 100 MHz. Buses like

SCSI Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices, best known for its use with storage devices such as hard disk drives. SCSI was introduced ...

and PCI fall in the megatransfer range of data transfer rate, while newer bus architectures like the PCI-X,

PCI Express PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe, is a high-speed standard used to connect hardware components inside computers. It is designed to replace older expansion bus standards such as Peripher ...

, Ultra Path, and HyperTransport / Infinity Fabric operate at the gigatransfer rate. The choice of the symbol ''T'' for ''transfer'' conflicts with the

International System of Units The International System of Units, internationally known by the abbreviation SI (from French ), is the modern form of the metric system and the world's most widely used system of measurement. It is the only system of measurement with official s ...

, in which T is the symbol for the tesla, a unit of magnetic flux density (so "megatesla per second" (MT/s) would be a reasonable unit to describe the rate of a rapidly changing magnetic field, such as in a pulsed field magnet or kicker magnet).

References

* * {{Cite web, url=http://www.knowledgetransfer.net/dictionary/Storage/en/megatransfer.htm, title=Definition: megatransfer, website=www.knowledgetransfer.net, access-date=2018-03-22
What does GT/s mean, anyway?

The relationship between transfer rate and clock rate
Computer performance Data transmission Temporal rates

Units

See also

References