ib files in root directory (windows)

[Jaroslav Uher]

Hi all,
I use Innodb tablespace and in root directory of my data disk I found some files beginning with ib (ib1, ib2, ib3 etc). About last 3 files are locked by mysqld, some of them have size 0 bytes, some contains transactions info like this (<10kB):

050720 16:35:48 Transaction:
TRANSACTION 0 115882, ACTIVE 0 sec, OS thread id 257 updating or deleting, thread declared inside InnoDB 499
mysql tables in use 1, locked 1
4 lock struct(s), heap size 320, undo log entries 1
...
...

After restart of mysqld are locked files released and created new ones with continued numbering.

Is it possible to specify different location (log directory) for these files?
What is purpose of ib files?

Thanks in advance.