That's actually a better point than you realize because crude oil is another special case! Typically, the steel drum barrel that we're all familiar with is a 55-gallon (208L) drum, except that crude oil barrels are 47 gallons (159 L).
So clearly the right thing to do here to clear up any confusion is to introduce the concept of computer-sized bytes, and metric bytes. Metric bytes would be 0.9765625 of a regular computer byte, so 1000 MB would be 1000 Metric Bytes, or 1024 * 0.9765625 = 1024 Bytes.
Thus hard drives could be rated at 1,000 GMB, for 1,000 giga metric bytes, which would really be a 1 TMB drive or 1 tera metric bytes, which is the same as 1024 giga regular-computer-sized-bytes, or 1024 GRCSB.
Totally straightforwards and not confusing to anybody.
So clearly the right thing to do here to clear up any confusion is to introduce the concept of computer-sized bytes, and metric bytes. Metric bytes would be 0.9765625 of a regular computer byte, so 1000 MB would be 1000 Metric Bytes, or 1024 * 0.9765625 = 1024 Bytes.
Thus hard drives could be rated at 1,000 GMB, for 1,000 giga metric bytes, which would really be a 1 TMB drive or 1 tera metric bytes, which is the same as 1024 giga regular-computer-sized-bytes, or 1024 GRCSB.
Totally straightforwards and not confusing to anybody.