5 ms·

How come we're still using bits-per-second and not bytes-per-second? Any reason other than being historical at this point?

pmorici 11y ago
Because the size of a byte isn't fixed. It is hardware dependent. There is no definitive standard defining what the size of a byte is. https://en.wikipedia.org/wiki/Byte https://en.wikipedia.org/wiki/Byte
- deleted 11y ago
  [deleted]
- rottyguy 11y ago
  I would be surprised if, practically speaking, 8bits <> 1 byte for 99.99% of all general applications. My feeling is that the .01% can do the math so the other 99.99% don't have to.
  - euyyn 11y ago
    Yeah but specifically for networking, error-detecting and error-correcting codes can make a byte at the app level > 8 bits on the wire, transparently. The capacity of the hardware is independent of that, so they talk in bauds.
LeonM 11y ago
Data is send serially over a fiber or copper line, bit by bit, not per byte. Also because bytes can be compressed, bits cannot, so giving the throughput in bits-per-second is an absolute value.
- rottyguy 11y ago
  Bytes can be compressed in sequence not in singularity (just as bits). I mean why don't we measure storage in bits and not bytes? Just seems unnecessarily confusing.
  - userbinator 11y ago
    Actually, memory chips (NAND flash, DRAM) are usually specified in terms of bits, usually using a lowercase 'b' to denote 'bit'. Online sellers have used this to their advantage, selling e.g. "1Gb" flash drives, with real 1 gigabit flash chips, which turn out to be ~128 megabytes.
    - Dylan16807 11y ago
      Or 120 megabytes.
jo909 11y ago
Even if the only reason is historical: why not, what advantage would bytes per second have?
- rottyguy 11y ago
  How long does it take to transfer a gigabyte file? Sure we can do the math but why (considering the average person)? Maybe there should be a common core revolution in engineering :-)
  - jo909 11y ago
    I can't do the exact math for that without looking up up a bunch of stuff. I don't how much I need to subtract for the multiple headers and other overhead, how fast the transfer rate gets to the maximum, how many packages get lost, what other factors of the congestion control algorithms might impact my transfer etc
    - Tepix 11y ago
      Try this bandwidth calculator (it's in German, but I think it's not hard to understand) http://www.heise.de/netze/tools/bandbreitenrechner/ http://www.heise.de/netze/tools/bandbreitenrechner/
      - jo909 11y ago
        You are missing my point: the raw bit rate of the network is not the rate of file transfers. There is a bunch of logic around the raw bits in the wire that make it mich more complicated than dividing by 8
        georgerobinson 11y ago
        For example, the TCP throughput equation which can be expressed by the following http://www.mathcs.emory.edu/~cheung/Courses/558/Syllabus/07-TCP-Anal/FIGS/TCP-TPut.gif http://www.mathcs.emory.edu/~cheung/Courses/558/Syllabus/07-... (depending on your degree of accuracy).

pmorici 11y ago

Because the size of a byte isn't fixed. It is hardware dependent. There is no definitive standard defining what the size of a byte is. https://en.wikipedia.org/wiki/Byte https://en.wikipedia.org/wiki/Byte

deleted 11y ago
[deleted]
rottyguy 11y ago
I would be surprised if, practically speaking, 8bits <> 1 byte for 99.99% of all general applications. My feeling is that the .01% can do the math so the other 99.99% don't have to.
- euyyn 11y ago
  Yeah but specifically for networking, error-detecting and error-correcting codes can make a byte at the app level > 8 bits on the wire, transparently. The capacity of the hardware is independent of that, so they talk in bauds.

LeonM 11y ago

Data is send serially over a fiber or copper line, bit by bit, not per byte. Also because bytes can be compressed, bits cannot, so giving the throughput in bits-per-second is an absolute value.

rottyguy 11y ago
Bytes can be compressed in sequence not in singularity (just as bits). I mean why don't we measure storage in bits and not bytes? Just seems unnecessarily confusing.
- userbinator 11y ago
  Actually, memory chips (NAND flash, DRAM) are usually specified in terms of bits, usually using a lowercase 'b' to denote 'bit'. Online sellers have used this to their advantage, selling e.g. "1Gb" flash drives, with real 1 gigabit flash chips, which turn out to be ~128 megabytes.
  - Dylan16807 11y ago
    Or 120 megabytes.

jo909 11y ago

Even if the only reason is historical: why not, what advantage would bytes per second have?

rottyguy 11y ago
How long does it take to transfer a gigabyte file? Sure we can do the math but why (considering the average person)? Maybe there should be a common core revolution in engineering :-)
- jo909 11y ago
  I can't do the exact math for that without looking up up a bunch of stuff. I don't how much I need to subtract for the multiple headers and other overhead, how fast the transfer rate gets to the maximum, how many packages get lost, what other factors of the congestion control algorithms might impact my transfer etc
  - Tepix 11y ago
    Try this bandwidth calculator (it's in German, but I think it's not hard to understand) http://www.heise.de/netze/tools/bandbreitenrechner/ http://www.heise.de/netze/tools/bandbreitenrechner/
    - jo909 11y ago
      You are missing my point: the raw bit rate of the network is not the rate of file transfers. There is a bunch of logic around the raw bits in the wire that make it mich more complicated than dividing by 8
      - georgerobinson 11y ago
        For example, the TCP throughput equation which can be expressed by the following http://www.mathcs.emory.edu/~cheung/Courses/558/Syllabus/07-TCP-Anal/FIGS/TCP-TPut.gif http://www.mathcs.emory.edu/~cheung/Courses/558/Syllabus/07-... (depending on your degree of accuracy).