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November 22nd, 2012 00:00
kB, kiB, MB, MiB, GB, GiB, TB and TiB
Ok, since 12 years already the storage industry agreed upon using the scientifically correct terms for Giga (meaning 1,000,000,000) instead of 1024x1024x1024. Even in course material these days this is promoted. Do me a favor and Google the word "Gigabyte" and see what you get! If you look at the Wikipedia document you'll get some perfect links to sites explaining the SI system. It's perfectly explained what the actual difference between GB and GiB is!!
So 1TB = 1000GB and 1GB = 1000MB and so on.
So I'm using Solutions Enabler (latest version 7.4) and to my surprise I'm seeing this:
512-byte Blocks : 92160000
MegaBytes : 45000
KiloBytes : 46080000
So 92,160,000 blocks of 512 bytes are available in a certain tdev. This is 92,160,000 x 512 = 47,185,920,000 bytes.
So how can this be only 45,000 Megabytes? Where's the 2,185,920,000 bytes that's gone missing?
And what's even more weird: If this tdev is 45,000 MB, why is this suddenly 46,080,000 bytes? All of a sudden I'm getting 1,080,000 kB back?
EMC, come on, get your facts straight and start using the correct abbreviations. So what do I now report to the host admin? How much GB did I just give him? 47.185, 46.08 or 45 ? Now what is it?
I think the easiest way to actually resolve this is to start using GiB (meaning 1024x1024x1024 bytes) and kiB (small k means kilo, because a large K represents Kelvin).
Any thoughts on this?
Avinash V
91 Posts
1
November 22nd, 2012 02:00
If I Refer
http://storagenerve.com/2010/03/22/emc-symmetrix-conversions-for-heads-tracks-cylinders-gb/
512-byte Blocks : 92160000
MegaBytes : 45000
KiloBytes : 46080000
92160000 * 512 = 47185920000 Bytes
47185920000/1024 = 46080000 KiloBytes
46080000/ 1024 = 45000 MegaBytes
45000 / 1024 = 43.9453125
RRR
2 Intern
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5.7K Posts
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November 22nd, 2012 03:00
So either Mr Storagenerve is wrong or Solutions Enabler is missing an "i" between the kB, MB and GBs. Mega means million, which is a 1 with 6 times a zero! This became a standard in the 2000 already.
1024 x 1024 Bytes is 1 MiB (Mebibyte). The EMC course material is actually being rewritten to reflect this and EMC pushes hard to the correct usage! Even exams now use GiB and GB, so pay attention!
Also mark that the k in kB is not a capital! A K means Kelvin which is a means to write down temperatures!
So 300K is NOT 300 kilobytes, but 300 kelvin! (http://physics.nist.gov/cuu/Units/units.html) Just the letter "K" is uppercase, but when written down as a word it's a small letter in "kelvin". So yes indeed, I paid attention in physics class!
0K is the absolute lowest temperature that can be achieved meaning -273 degrees Celcius or almost -460 degrees Fahrenheit