Dell Technologies Principal Software Engineer interview questions

The Interview process is one of the worst process in dell, first round was telephonic where i am hardly understand the voice and way question asked, the interview was cleared and then for second round of interview they started me to come only on office hours in between of 10 to 4, and that is also on next immediate working day, after reaching on Dell for FTF, the panel was so unprofessional behaving, two person came for interview without any preparation & question, during interview they both are started discussion next what we need to ask (topic & question), and after each question i had only followed question HOW?, the panel don't even know about detail and simply asking HOW?, after a while one of them asked me write fibonacci series, i wrote the program by recursive and then he asked me to write same with loop, once i wrote that and after i started with pros & cons on both code, both of the interviewer looks like not interested on explanation and started discussion to each other. feel very unprofessional & looks like interviewer doesn't have interview taking ethics.