I found out about the job through my network, it was not posted online. I was told by someone I met who worked at Nvidia to send her my resume. I was not able to find the job posting or a job description online, so I didn't write a cover letter, nor was I asked to. I was then invited to interview on site. When I got to the interview, the first question I was asked was why I didn't write a cover letter. It was a strange way to start an interview and didn't feel very welcoming. When I found out I didn't get the job, they asked to share feedback and then told me that I only sent a thank you to one person, and not another person, and that I should have sent a thank you to both. When I tried explaining that I was planning to send a thank you, but the person had reached out to me first, the woman laughed. It was a terrible experience. I have since made a career transition and now work in recruiting. This is not an appropriate way to recruit someone. Hopefully they have changed their recruitment process since then. This interview was in 2014.