GCMS: Global Case management system
Its an application system used by CIC for updating the various details pertaining to your application at every stage of the assessment. My understanding is that it also includes an electronic copy of your application along with the supporting documents for a visa officer to review your application using one single interface.
It may include several features just like a CRM interface.
GCMS notes consists of various markers, kindly google a sample of GCMS notes.
It only gives you any idea about the stage of your application and highlights important factors like Misrepresentation and also if security checks have been performed.
It costs about CAD 5 when requested via a Canadian National or PR holder and CAD 30 when requested online via a website.
It takes upto 30 days to receive your GCMS and it may not reflect a true picture of your application status due to the elapsed time.
Cheers