This came up when I was doing some work with our new backup vendor's API, pulling out their backup numbers all reported in bytes and converting to Gb or Tb for our cacti graphs.
set bytes=7696581394432 echo $bytes bytes = `echo $bytes"/1024/1024/1024/1024" | bc` Tb 7696581394432 bytes = 7 Tb
But the numbers on the vendors dashboard were different. I asked vendor support and the next day they confirmed (as I suspected) they were converting using powers of 10 But what I did not know, was this was on purpose due to the disk manufacturer's convention: http://en.wikipedia.org/wiki/Hard_disk_drive#Units
For someone with a computer science background this was surprising to not have uniform definitions of units across media
Ram manufacturers don't do this according to the article they use (do Flash or SSD makers?)
So if I have full 1Tb RAM drive and try to copy it to a 1Tb HDD, it won't fit - I'll need 9.95% more space due to the different definitions of Tb
Made me wonder what the Netapp reporting tools, OpsMgr, System Manager, DFM etc do when reporting the #bytes available on a HDD as Tb do they do binary or decimal conversions?
What are some other implications of the unit definition difference?
thanks