Background job

Hi,

I have defined a job in SM36 and i can see the status in SM37. But i have created couple of jobs with the same name ZTEST the parameters are different each time with different timings. each is a periodic job. Which one of these is valid? or all of them will run? I am not sure how to edit a scheduled job, delete a scheduled job. If i delete a job in SM37 is it as good as deleting it permanently?

Where can i see the list of jobs scheduled apart from SM37?

Also i wonder why am i not able to see the spool for this job. When i scheduled this job earlier with out a periodidc job i could see the spool.

Please answer these questions.

Thanks.