[NTLUG:Discuss] Apparent Disk Space Shrinkage During Formatting (was ext3 waste disk spaces then Windows ME?)

[Robert Pearson]

On Apr 25, 2006, at 1:17 PM, Chris Cox wrote:
>> On Apr 25, 2006, at 11:20 AM, m m wrote:
>>
>> I just notice that my 160 G hard drive "shrinked" to 140 (145?) G hard
>> drive after formatted to ext3 file system and mounted to my linux box.
>>
>> I used to use that 160 G HD as WIN ME box, at that time I still have
>> about 150  G total spaces.
>>
>> Each  file system have its advantages. but is it worth to  sacrifice
>> about 10G to use another file system?

> Seems a bit extreme.  There's always the journal.. but it's
> relatively small in comparison to the overall disk size on the
> larger disks.
>
> fat32 is a pretty simplistic file system.  10G still sounds a bit
> extreme to me... but you're not alone...
>
> Using reiserfs on my 900G drive yields
> 878865140K (840G)
>
> I feel your pain.

There were several very accurate, correct and good answers
to this "apparent" formatting "shrinkage over and above the
required disk overhead loss. I stumbled across this information
by accident today and wanted to share it.
Take a look at the "Binary prefix" page at Wikipedia---

<<http://en.wikipedia.org/wiki/Binary_prefix>>

In particular the chart---
"Approximate ratios between binary prefixes and their decimal equivalent"

Further below the chart the Section titled "Usage notes" has one
paragraph that states---

"Modern-day PC users, of course, regard both RAM and disk as kinds
of storage and expect their capacities to be measured in the same way.
Operating systems usually report disk space using the binary version.
To the purchaser of a "30 GB" hard drive, rather than reporting either
"30 GB" or "28 GiB", Microsoft Windows reports "28 GB". This creates
hard feelings that have even led to legal disputes, sometimes made
worse by other technical issues such as failure to distinguish between
unformatted and formatted capacities and to account for the overhead
inherent in disk file systems."


This page, for me, cleared up a lot of questions and confusion.