Why is file size measured in megabytes but internet speed measured in megabits?
In: Technology
Tradition mostly at this point.
Up until the dial up modem and ISDN point, a common way of measuring transfer speeds was Baud alongside the bitrate.
Baud was a way of measuring transfer speed going back to the morse telegraph and measured in symbols per second.
People cared about how fast the text they were sending was transmitted and not the underlying technology. And the bit-per-second to baud ratio could vary quite a bit.
If you transferred pure ASCII characters you could encode on character with only 7 bit, but computers quickly standardized to a single character being represented by an 8 bit byte.
How much data in bytes you transferred over a line with a fixed bit-rate could depend on the encoding scheme that was used.
Baud was dropped eventually as a relic of an analogue past and transfer speed came to be measured in bits per second, not only because that was a large number, but also because it was a consistent number.
The people who provided the technology could advertise their connection in bits per second and what the user gout out of it in bytes per second was their problem.
The gross bit rate is something fixed and guranteed on a hardware level. the effective bitrate and the resulting bytes are depending on overhead in various protocols, compression, error correction and other stuff that the people responsible for the hardware have little influence over.
So bitrate is what is promised, byte rate is what you make of it.
It of course helps that 1 terabit per second sounds a lot more impressive than 125 gigabytes per second max with around 110 gigbytes in normal usage.
Latest Answers