Oradim & Certification

New to this list and am about to embark on getting my Oracle DBA certification so will probably end up asking u lot some daft questions, but hopefully i in turn can help others out soon. To start off with i have a couple of queries the first about certification and the second about oradim.

First...
Been working with oracle for about 2.5 years as a developer and touched on DBA stuff having done a 1 week hands on course some time ago not having strained myself it's now time to get my nose amongst the books and i would like to ask you how long do u think it should take an average joe to complete the DBA certification doing evening study 5/6 times a week for a couple of hours? If you can't relate to this how did u do the certification and has it improved your ability/job lot in the market, ?

Second...
Having created the service and instance successfully, i think? but where is the log file to verify this, tried to look in my oracle_home\rdbms but no log file, am using 8.1.6 server. When i run oradim to create a service and instance, does it do it immediately or do i have to reboot? Can i take it that an instance is running in memory? Oradim confuses me! Have tried... D:\>oradim - shutdown -sid fistsid -usrpwd system -shuttype srvc,inst -shutmode i DIM- 00018: Failed to stop Oracle Service O/S-Error: (OS 1060) The specified service does not exist as an installed service.

Cheers
Rex Received on Sun Mar 18 2001 - 19:11:19 CST