# Use of MB vs MiB, GB vs GiB, TB vs TiB etc

• Ref: https://forum.pfsense.org/index.php?topic=106470.0 where we start reporting TB.

Ref: https://en.wikipedia.org/wiki/Petabyte and table of "standard" abbreviations.

The metric system has kB MB GB TB … for 10^3 10^6 10^9 10^12 ...

JEDEC (somewhat unfortunately) allows KB MB GB for 1024 1024^2 1024^3

IEC uses KiB MiB GiB TiB ... for 1024 1024^2 1024^3 1024^4...

Should we switch to KiB MiB GiB TiB ... in the places where the calculation is being done in powers of 1024?

• I've always used upper/lower case to designate multiplier of 1000 vs. 1024, and bits vs. bytes.

k = 1000^1
m = 1000^2
g = 1000^3
t = 1000^4

K = 1024^1
M = 1024^2
G = 1024^3
T = 1024^4

b = bits
B = bytes

So for example.
n KBps = n x 1024^1 bytes per second.
n MBps = n x 1024^2 bytes per second.
n GBps = n x 1024^3 bytes per second.
n TBps = n x 1024^4 bytes per second.

n kbps = n x 1000^1 bits per second.
n mbps = n x 1000^2 bits per second.
n gbps = n x 1000^3 bits per second.
n tbps = n x 1000^4 bits per second.

• @Phil, IMHO a better Wiki article is the definition for Gigabyte (Consumer Confusion):

https://en.wikipedia.org/wiki/Gigabyte#Consumer_confusion

• I've always used upper/lower case to designate multiplier of 1000 vs. 1024, and bits vs. bytes.

k = 1000^1
m = 1000^2
g = 1000^3
t = 1000^4

K = 1024^1
M = 1024^2
G = 1024^3
T = 1024^4

b = bits
B = bytes

So for example.
n KBps = n x 1024^1 bytes per second.
n MBps = n x 1024^2 bytes per second.
n GBps = n x 1024^3 bytes per second.
n TBps = n x 1024^4 bytes per second.

n kbps = n x 1000^1 bits per second.
n mbps = n x 1000^2 bits per second.
n gbps = n x 1000^3 bits per second.
n tbps = n x 1000^4 bits per second.

Fully agree.
No reason for that 'i' in between. Looks dull also.

• I don't have a strong preference here either way. Though I will say that when I see, for example "MB" I don't assume one way or the other, though when I see MiB I can safely assume it's 1024.

I'm much more pedantic about B=byte and b=bit

• Steve B merge PR https://github.com/pfsense/pfsense/pull/2605 so I guess at least he liked the MiB.

• Since we're being pedantic about MB vs MiB, I think we also need a way to indicate what size of "byte". Since people get confused about MB, surely they realize the definition of "byte" varies on context, especially in networking. /sarc

I would vote for using the "proper" abbreviation if only to reduce the confusion for laypersons and it's much harder to typo a missing "i" than "B" vs "b".

edit: MiO  MebiOctet. We should use that.

• Found system->Advanced->Miscellaneous, section "RAM Disk Settings (Reboot to Apply Changes)"

Sizes are in MB and not like above abbreviation.

• Found system->Advanced->Miscellaneous, section "RAM Disk Settings (Reboot to Apply Changes)"

Sizes are in MB and not like above abbreviation.

Pull request https://github.com/pfsense/pfsense/pull/2696

From what I can see, you are right. The underlying FreeBSD mdmfs utility creates a 40 MiB memory disk when -s 40m is specified.