Megatransfer
Encyclopedia
In computer technology, transfers per second and its more common derivatives gigatransfers per second (abbreviated 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, 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. 1 MT/s is 106 or one million transfers per second. In the US/short scale
, 1 GT/s means 109 or one billion transfers per second.
These terms alone do not specify the bit rate
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 order to calculate the data transmission rate, one must multiply the transfer rate by the information channel width. For example, a data bus 8 bytes wide by definition transfers 8 bytes in each transfer operation; at a transfer rate of 1 GT/s, the data rate would be 8x109 bytes/s, i.e., 8 GB/s, or approximately 7.45 GiB
/s.
Expanding the width of a channel, for example that between a CPU and a northbridge
, increases data throughput 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
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 200 MT/s, because there are 100 million rising edges per second and 100 million falling edges per second of a clock signal running at 100 MHz.
SCSI
(Small Computer Systems Interface) falls in the megatransfer range of data transfer rate, while newer bus architectures like the front side bus
, Quick Path Interconnect, PCI Express
and HyperTransport
operate at the rate of a few GT/s.
Long and short scales
The long and short scales are two of several different large-number naming systems used throughout the world for integer powers of ten. Many countries, including most in continental Europe, use the long scale whereas most English-speaking countries use the short scale...
, 1 GT/s means 109 or one billion transfers per second.
These terms alone do not specify the bit rate
Bit rate
In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....
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 order to calculate the data transmission rate, one must multiply the transfer rate by the information channel width. For example, a data bus 8 bytes wide by definition transfers 8 bytes in each transfer operation; at a transfer rate of 1 GT/s, the data rate would be 8x109 bytes/s, i.e., 8 GB/s, or approximately 7.45 GiB
Gibibyte
The gibibyte is a standards-based binary multiple of the byte, a unit of digital information storage. The gibibyte unit symbol is GiB....
/s.
- The formula for a data transfer rate: Channel width (bits/transfer) × transfers/second = bits transferred/second
Expanding the width of a channel, for example that between a CPU and a northbridge
Northbridge (computing)
The northbridge has historically been one of the two chips in the core logic chipset on a PC motherboard, the other being the southbridge. Increasingly these functions have migrated to the CPU chip itself, beginning with memory and graphics controllers. For Intel Sandy Bridge and AMD Fusion...
, increases data throughput 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
Computer bus
In computer architecture, a bus is a subsystem that transfers data between components inside a computer, or between computers.Early computer buses were literally parallel electrical wires with multiple connections, but the term is now used for any physical arrangement that provides the same...
running at double data rate
Double data rate
In computing, a computer bus operating with double data rate transfers data on both the rising and falling edges of the clock signal. This is also known as double pumped, dual-pumped, and double transition....
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 200 MT/s, because there are 100 million rising edges per second and 100 million falling edges per second of a clock signal running at 100 MHz.
SCSI
SCSI
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
(Small Computer Systems Interface) falls in the megatransfer range of data transfer rate, while newer bus architectures like the front side bus
Front side bus
A front-side bus is a computer communication interface often used in computers during the 1990s and 2000s.It typically carries data between the central processing unit and a memory controller hub, known as the northbridge....
, Quick Path Interconnect, PCI Express
PCI Express
PCI Express , officially abbreviated as PCIe, is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP bus standards...
and HyperTransport
HyperTransport
HyperTransport , formerly known as Lightning Data Transport , is a technology for interconnection of computer processors. It is a bidirectional serial/parallel high-bandwidth, low-latency point-to-point link that was introduced on April 2, 2001...
operate at the rate of a few GT/s.
See also
- Data transfer rate, also known as Data rate or Peak bit rate
- Data transmissionData transmissionData transmission, digital transmission, or digital communications is the physical transfer of data over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibres, wireless communication channels, and storage media...
, also known as digital transmission - Data rate unitsData rate unitsIn telecommunications, bit rate or data transfer rate is the average number of bits, characters, or blocks per unit time passing between equipment in a data transmission system. This is typically measured in multiples of the unit bit per second or byte per second.- Avoiding confusion :To be as...
such as bit/s (bps) - Parallel portParallel portA parallel port is a type of interface found on computers for connecting various peripherals. In computing, a parallel port is a parallel communication physical interface. It is also known as a printer port or Centronics port...
- Symbol rateSymbol rateIn digital communications, symbol rate is the number of symbol changes made to the transmission medium per second using a digitally modulated signal or a line code. The Symbol rate is measured in baud or symbols/second. In the case of a line code, the symbol rate is the pulse rate in pulses/second...
(BaudBaudIn telecommunications and electronics, baud is synonymous to symbols per second or pulses per second. It is the unit of symbol rate, also known as baud rate or modulation rate; the number of distinct symbol changes made to the transmission medium per second in a digitally modulated signal or a...
) - Transmission (telecommunications)Transmission (telecommunications)Transmission, in telecommunications, is the process of sending, propagating and receiving an analogue or digital information signal over a physical point-to-point or point-to-multipoint transmission medium, either wired, optical fiber or wireless...
- File transferFile transferFile transfer is a generic term for the act of transmitting files over a computer network or the Internet. There are numerous ways and protocols to transfer files over a network. Computers which provide a file transfer service are often called file servers. Depending on the client's perspective the...
- Maximum throughput
External links
- Megatransfer (definition)
- What does GT/s mean, anyway?