Increments of 700 MB. As laid down by the wizards of usenet: 1CD, 2CD, 3CD, etc.
And then extending that idea, 1.44 MB, 4.7 GB, and 50 GB units.
A disk is 1,510,294 bytes - because it’s 1.44 American megabytes, and a kilobyte is 1024 bytes, god dammit. They’re binary. A CD (or “disc”) is 486 disks. A DVD5 is 6 CDs, because a DVD9 only holds 12. A BDRXL is 24 DVD5s.
From there we have to defer to the other kind of “elders of the internet” and say a “terabit” is exactly 10 BDRXLs, because my dad absolutely refuses to use the word “terabyte.” It’s decimalized from there on out. Which sounds great until you realize an American terabit is 5.7% more than asinine SI “hard drive manufacturer” terabytes, but only 98% of a proper binary figure given the even dumber name “tebibyte.”