GIB & MIB vs. GB and MB

overkill · 08-01-2021, 12:03 PM

Hi guys. Is there an easy way to convert MIB and GIB to GB and MB, so I get an exact size that I want like 30GB? It's very confusing with some installers.

business_kid · 08-01-2021, 01:38 PM

Yes. Enter the terms in a search engine.

The problem arises because 1000 or 1K is mathematically used, but electronics uses 1024. So 1 Megabyte=1024*1024 and ever multiple is just multiplied by 1024. Gigibytes are a marketing ploy to save tome silicon but it makes very little odds.

shruggy · 08-01-2021, 03:56 PM

Code:

$ units -t 30GB GiB
27.939677
$ units -t 30GiB GB
32.212255

So, 30 GB ≈ 27.94 GiB and 30 GiB ≈ 32.21 GB

Obviously, units is not the only possibility. E.g., numfmt which is part of GNU coreutils since 8.21 (Feb 2013):

Code:

$ numfmt --from=si --to=iec --round=nearest 30G
28G
$ numfmt --from=iec --to=si --round=nearest 30G
32G

or Qalculate!

Code:

$ qalc -t 30Gbyte to Gibyte
27.939677 gibibytes
$ qalc -t 30Gibyte to Gbyte
32.212255 gigabytes

And as long as you are comfortable with doing conversions yourself, pretty much any calculator will do:

Code:

$ bc<<<'scale=1;30*10^9/1024^3'
27.9
$ bc<<<'scale=1;30*1024^3/10^9'
32.2
$ dc -e '1k10 9^30*1024 3^/p'
27.9
$ dc -e '1k1024 3^30*10 9^/p'
32.2

fatmac · 08-02-2021, 04:01 AM

Basically, all you need to know is that manufacturers use MB, because you get more of them, than you do with genuine standard computer sizing (MiB), which is 1024 as against 1000 units used by manufacturers - just a marketing ploy.

overkill · 08-02-2021, 04:15 AM

I was never good in math

overkill · 08-02-2021, 04:21 AM

Quote:

Originally Posted by business_kid

Yes. Enter the terms in a search engine.

The problem arises because 1000 or 1K is mathematically used, but electronics uses 1024. So 1 Megabyte=1024*1024 and ever multiple is just multiplied by 1024. Gigibytes are a marketing ploy to save tome silicon but it makes very little odds.

Yea I have done that, but it's still a bit confusing.

4 GB = 3814.7 MIB

4 GB = 3.725290298 GiB

In the above example, for my swap, do I put 3725 GIB or 3814 MIB in the partitioner?

pan64 · 08-02-2021, 04:45 AM

Quote:

Originally Posted by overkill

Yea I have done that, but it's still a bit confusing.

4 GB = 3814.7 MIB

4 GB = 3.725290298 GiB

In the above example, for my swap, do I put 3725 GIB or 3814 MIB in the partitioner?

usually none of them. You will tell the first/last sector. That's all. You do not need to know if it was exactly 3.73452345 GB or 3.783456245 GB (or anything else).

shruggy · 08-02-2021, 05:44 AM

Quote:

Originally Posted by overkill

In the above example, for my swap, do I put 3725 GIB or 3814 MIB in the partitioner?

1) Don't forget the decimal point: 3814MiB=3.725GiB;
2) For swap size, I'd prefer "round" "binary" numbers anyway, i.e. 4GiB or 4096MiB.¹
________
¹ When dealing with computers, I perceive powers of two rather than powers of ten as round numbers. So e.g. 4096 to me is a nice, perfectly round number, while 4000 not so much. FYI, 1GiB=1024MiB=1048576KiB

fatmac · 08-02-2021, 01:33 PM

Quote:

Originally Posted by overkill

..... for my swap, do I put 3725 GIB or 3814 MIB in the partitioner?

Just put 4G, the partitioner will give you a size as near as possible, which is all that you would need.

overkill · 08-03-2021, 01:57 PM

Quote:

Originally Posted by fatmac

Just put 4G, the partitioner will give you a size as near as possible, which is all that you would need.

I know but i'm a perfectionist lol I like it to be even numbers and what I want not near as possible