Hi
GCMS notes are an in depth look at what is happening with your file.
They tell you where your file is at the VO, ex. Registry, Put Away etc.
They contain personalized notes written by the officer processing your file regarding your relationship and application.
They contain updates on your assessments- Eligibility, CRIM/SEC, Medical etc and show you when they were last worked on.
Pretty much everything you need to know about your file is in these notes.
They take up to 30 days to be sent to your email.
I order them again each time they arrive.
http://www.cic.gc.ca/english/department/atip/requests-atip.asp