Linux, it just does not add up!

4 Nov 2003

Today I noticed something very strange on a few Linux machines.

I needed a 10 Mb file to do some bandwidth tests, I would just put it on a web server and download it often. I used dd to create a file that I thought was 10Mb and checked it with du -h:

# dd if=/dev/urandom of=10megfile.dat bs=1024 count=10240
# ls -l 10megfile.dat
-rw-r--r--    1 root     root     10485760 nov  4 16:38 10megfile.dat
# du -h 10megfile.dat
11M     10megfile.dat

So I thought I am going mad since surely du cannot be wrong, I checked with the Google Calculator and it agrees, 10 485 760 bytes does make 10 Mb.

I then checked the same on FreeBSD and it finds it as 10Mb, RedHat 6.2 agrees it is 10Mb but RedHat 7.2 and a number of Mandrake machines thinks it is 11Mb.

I guess I need to have a chat with bug-fileutils@gnu.org

Posted by R.I.Pienaar on Tuesday, November 4, 2003 at 4:34 PM

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