Throughout my technological lifetime I followed the convention that *1 kB *was equal to *1000 bytes *and that *1 KB *was equal to *1024 bytes*. Similarly, *1 mB *was *1 000 000 bytes*, and *1 MB* was *1 048 576 bytes*.

In dial-up Internet days, we surmised that a 56K modem transferred data at a rate of 56 000 bits per second (that is, 56 kbps or 5.6 kBps). Therefore, dividing the nominal modem speed by 10 gave a simple divisor for quickly calculating the download times of files with sizes expressed in *kB*, that is,

`download time in seconds = file size in kB / modem speed in kBps`

In reality, however, this was no more than a loose convention adopted by Internet users to express data volumes and bandwidths, and distinguishing between 1000 bytes and 1024 bytes by using kB and KB in writing was very convenient.

I continued with this convention until comments from a heated debate on reddit informed me of the 1999 IEC 60027-2 standard, which introduced the *kibi* and removed all ambiguity. *The MB Confusion* blog post explains this standard in a more interesting way than the Wikipedia article.