How much do grad schools care about my dismissal experience in my application? I am an international student from China and currently pursuing undergraduate degree in Canada, majoring in computer sicence. My academic experience is very tortuous and I want to tell my story and ask my chance to be considered for the phd study.
This is my second undergraduate study. I got my first honor degree in ECE at University of Windsor, Canada with distinction in 2015, standing at the top 15% of graduated students with a GPA of 83/100 (It doesn't look amazing but the university gave low grade to students). Afterwards I worked for 2 years in related industry. During the work, I found what I was more interested about is computer science. However, without a single computer science course taken, I find myself lack appropriate academic training. I planned myself to pursue a master degree in US. After getting a GRE score of 324 with 4.0 in analytical writing, I fortunately got admitted by Columbia University in 2017. This turned out to be a horribly overwhelming experience possibly because I lacked the foundations of computer science, I got academically dismissed 1 year after for not being able to maintain a gpa higher than 3.0. After a thorough retrospection, I made my decision to get a second bachelor degree in computer science in Canada. Right now, I'm 1 year to graduation with a GPA of 89/100 (not sure about the rank but should be close to top 1st or 2nd). I do get involved in some research projects with professors during summer, though I got no publications. However, the experience in Columbia seems to haunt me. So here I have some questions regarding the application:

I acknowledge that I have to include the dismissal experience in my application. The question is when calculating GPA, does the grades in Columbia take into account for the overall GPA or the GPA's are seperated for each institution I've attended?

How much will admission committee care about the dismissal experience? I did perform poorly in academics during some period of my life, but I think I have recovered from that not only in terms of mentality and maturity but also improvement in my ability of study. Will this experience kill my chance to get considered?


Thanks for any comment
without a single computer science course taken, I ... got admitted by Columbia University

If Columbia admitted someone who had never taken a course in CS to their masters degree in CS, I'd say they probably made a mistake.  A surprising one.  It's clear to me that the problem was

You did not know you were enrolling in a degree that is not for CS beginners
Columbia did not realize you were a CS beginner.
You are not a CS beginner any more, so this whole situation is no longer relevant.


does the grades in Columbia take into account for the overall GPA or the GPA's are seperated for each institution I've attended?

Each institution will compute its own GPA.  It would be unreasonable to combine them, as each university has its own grading system.

How much will admission committee care about the dismissal experience?

If you explain the circumstances (not prepared for the degree program) and what you did about them (second bachelors degree with good grades) then I think most admissions committees will consider your more recent grades to be more important.
You should seriously consider if you have any use for more degrees.  You might have enough already.